INHALANTS

OFFICIAL NAMES: Aerosol propellants, medical anesthetic gases, amyl nitrite, butane, chlorofluorocarbons, chloroform, ether, halothane, isobutyl nitrite, nitrous oxide, toluene, organic solvents, refrigerant gases, volatile solvents

STREET NAMES: Aimies, air blast, ames, amys, aroma of men, bolt, boppers, bullet, bullet bolt, buzz bomb, climax, discorama, hardware, heart-on, highball, hippie crack, honey oil, huff, kick, laughing gas, lightning bolt, locker room, Medusa, moon gas, Oz, pearls, poor man's pot, poppers, quicksilver, rush, rush snappers, Satan's secret, shoot the breeze, snappers, sniff, snotballs, spray, Texas shoe-shine, thrust, toilet water, tolly, toncho, whippets or whippits, whiteout

DRUG CLASSIFICATIONS: Not scheduled

OVERVIEW

Inhalant is a term applied to an estimated 1,000 to 1,400 legal products used in households, industry, businesses, and medical settings. These products are as common as a felt-tip marker, a bottle of correction fluid or nail polish remover, a tank of gasoline, a tube of model airplane glue, air freshener or vegetable cooking spray, or a can of silver spray paint.

Inhalants contain chemicals that are volatile, meaning they evaporate or vaporize quickly. When someone inhales a concentrated amount of these vapors, the vapors affect his or her normal mental functioning.

Inhalant abuse refers to the intentional inhalation of such products to experience a carefree, euphoric high. The exact mind-altering effects of inhalants vary, depending on the product involved, but they are generally similar to those produced by alcohol intoxication or anesthesia. The health ramifications can be serious, in both the short and long term, because most inhalants are highly toxic.

Hundreds of thousands of Americans experiment with inhalants for the first time each year, according to results of the 2000 National Household Survey from the Substance Abuse and Mental Health Services Administration (SAMHSA), an agency of the U.S. Department of Health & Human Services. The survey found that in 1999, one million Americans tried inhalants for the first time—the highest annual number of inhalant initiates since 1965. The 1998 estimate of new inhalant abusers was 918,000; in 1997 it reached 975,000.

Volatile solvents are useful in industry and in homes because of their ability to dissolve fat. When inhaled, however, this property poses problems to the brain and the network of nerves that connect the brain and spinal cord to the rest of the body. "...thus, because the brain is a lipid-rich organ, chronic solvent abuse dissolves brain cells," the American Academy of Pediatrics wrote in a 1996 policy paper about inhalants. The chemical vapors also damage the myelin sheath, the fatty wrapper that insulates the fibers of many nerve cells that carry signals.

Solvent abusers can die, sometimes after a single prolonged episode of sniffing, from either physical effects of the chemicals or dangerous behavior related to the user's impaired state of mind. The National Inhalant Prevention Coalition, a nonprofit organization based in Austin, Texas, records 100 to 125 deaths from inhalantsa year, a number it considers a partial measure. The United States has no central system for logging deaths and injuries from inhalant use.

Though inhalants are legitimate, legal products, the consequences of their misuse have led 38 state legislatures in the United States to enact laws governing their sale and possession to minors. In the United Kingdom as well, prevention efforts include legislation that makes possession of volatile substances more difficult for youth.

Scientists differ in their exact definition of inhalants. However, inhalants generally meet three criteria: they are volatile at room temperature; they are not already part of a distinct class of inhaled drugs, such as nicotine or cocaine; and they are inhaled, by various means, to alter the user's consciousness.

In 2001, the annual Monitoring the Future study (MTF), conducted by the University of Michigan and funded by the National Institute on Drug Abuse, found that 17.1% of eighth graders had abused inhalants at some point in their lives. In 1995, the National Household Survey on Drug Abuse found inhalants to be the second most commonly abused illicit drug by American youth ages 12 years to 17 years, after marijuana.

History

The intoxicating action of certain chemical vapors is not a new discovery. Some researchers have claimed that Pythoness, a mystic in ancient Delphi, delivered her famous oracles while under the influence of heady fumes escaping from an underground cavern.

In the 1770s, Sir Joseph Priestly, an English chemist, discovered nitrous oxide (laughing gas). In 1799, Sir Humphrey Davy suggested it could be used to reduce pain during surgery. In nineteenth-century North America, Europe, and Great Britain, anesthetics (nitrous oxide and ether) and volatile hydrocarbons were inhaled for recreation. In the early twentieth century, the fashion turned to inhaling ether and chloroform, a toxic, volatile liquid then being used as a general anesthetic.

In the 1940s and 1950s, abusers began inhaling gasoline. A report of a youth's addiction to gasoline was printed in the scientific literature in the early 1960s, and gasoline remains a dangerous and widely abused inhalant around the world. Also in the 1960s, sniffing glue—such as the type used in building model airplanes—became popular among some youths, and glue sniffing remains popular today.

Inhalant abuse can also be a hazard in some occupations. People who work in the refrigeration industry may abuse Freon, hydrocarbons used in refrigerants; and people working in medical fields may abuse nitrous oxide. A 1979 study, "Abuse of Nitrous Oxide," published in Anesthesia & Analgesia, found that 20% of dental and medical students had abused nitrous oxide.

Most abusers are drawn to inhalants for their psychoactive, or mind-altering, effects. Users of nitrites are the exception. The nitrites make up an inhalant subcategory that includes amyl, butyl, and cyclohexyl nitrites. These substances were nicknamed poppers because in the past, they were packaged in ampules. Users cracked the ampules to release the vapors. Nitrites are abused, internationally, because they produce a sexual rush, accompanied by a sense of power and exhilaration.

Nitrites were highly popular in the United States in 1970s, particularly in the gay community. One study, published in 1988 in the National Institute of Drug Abuse Research Monograph Series, reported that by 1979 up to five million people used nitrites weekly. By the early 1980s, however, nitrite use dropped dramatically. In the United States, amyl nitrite became available solely by prescription in 1979. Also, nitrite use was associated with Kaposi's sarcoma, the most common cancer affecting people with AIDS.

Amyl nitrite's place on the streets has largely been taken by butyl nitrite, a similar chemical with milder effects. These products, sold as "room odorizers" under such brand names as Locker Room and Rush, are often available at head shops, concerts, raves, and dance clubs.

Legal, accessible, dangerous

Re-Solv, a nonprofit group in the United Kingdom that works against solvent abuse, claims that the average home contains about 30 abusable products.

Because they are readily available, inhalants may be the first drug with which children and adolescents experiment—preceding cigarettes. The products are inexpensive or can be easily shoplifted, and many are as close as a kitchen cupboard or utility closet. In addition, inhalants can be easily hidden and are sold legally, factors that contribute to their widespread use. Inhalants are also popular because they produce a high that, in general, hits fast and wears off quickly.

Inhalants' everyday nature may lead some young people to think that the substances are harmless. In addition, risk-taking adolescents may believe they are different and immune to damage, and thus dismiss health warnings about inhalants.

In fact, inhalants can kill, either from accidental causes related to their use, side effects, or a syndrome called sudden sniffing death. Even when inhalant use is not fatal, it can cripple users' bodies and minds. Research has shown that even short-term inhalant use can damage brain functioning over the long term. It also can trip up different parts of the nervous system, including nerve pathways and the brain's cerebral cortex, cerebellum, and hippocampus. Depending on the chemicals involved, inhalants damage the heart, liver, kidneys, bone marrow, and lungs, and also reduce the blood's ability to carry oxygen. Inhalant users may also develop hearing, vision, immune system, and muscle damage over the long term.

In the 1960s, people talked of glue sniffing as "melting your brain." Indeed, brain scans of long-term heavy toluene abusers (an industrial solvent common in many inhaled substances, including glue) show visible shrinkage of brain tissue.

USAGE TRENDS

Much inhalant use is confined to early adolescence. But some users become dependent, and they continue abusing inhalants into adulthood. For other users, inhalants may be the first stop on a long path of misusing dangerous substances.

A study published in 2000 in the Journal of Sub-stance Abuse compared three groups of college students at a university in New Mexico: Those who had used inhalants before age 18; those who smoked marijuana before age 18 (but did not use inhalants); and those who used neither marijuana nor inhalants before age 18. Researchers reported that early use of inhalants greatly increased college students' risk of frequent drinking, binge drinking, smoking, and illicit-drug use. Compared with early marijuana use alone, early inhalant use was associated with twice the rate of binge and frequent drinking, and significantly greater rates of tobacco and drug use. The researchers suggested that universities identify early inhalant users and target them for special intervention and prevention efforts.

In a study of imprisoned youth in Canada, published in the October 1999 issue of the American Journal of Drug and Alcohol Abuse, many participants cited inhalants as their first substance of abuse, preceding cigarettes, marijuana, illegal hallucinogens, and opiates.

Age, gender, and ethnic trends

The authors of the two studies mentioned above emphasized that this progression does not necessarily mean that young people who use inhalants will later move on to other drugs. Instead, the factors that make youths vulnerable to inhalant use—social and environ-mental influences, parents, biology and genetics, emotional and learning disorders, attitudes, personality, and behavior—may also increase the likelihood of their turning to other mood-changing substances. Regardless of why inhalant use begins, early inhalant use has been found to increase users' risk of developing drinking and drug problems later in life.

Some researchers have identified adolescent depression as playing an important role in predicting who begins to use, or continues to use, illicit substances. In studies, inhalant users were found to suffer more emotional problems—particularly depression, anxiety, and anger—than those who used other drugs or did not use drugs at all. Inhalant abusers who seek treatment have high rates of psychological illnesses, especially conduct and personality disorders, and typically are dependent on another drug.

Considering the widespread abuse of inhalants, little scientific research has been done on the subject. Conducting research is complicated because inhalants are not limited to one basic compound but include a wide range of chemicals and products.

In 2002, the National Institute on Drug Abuse (NIDA) dedicated about $2 million to fund studies on the nature and extent of inhalant abuse. NIDA sought proposals for research in the following areas: different types of abused substances; socio-cultural, socioeconomic, gender, and regional differences in use; and factors associated with individuals' risk of, vulnerability to, protection against, and resistance to inhalant abuse.

Many research questions remain about the role that factors such as family, role models, existing health problems (such as mental illness, HIV/AIDS, or alcohol abuse), and peer influences play in a young person's decision to start, continue, increase, or stop abusing inhalants.

Categorizing inhalants

The general category of inhalants is broken into smaller categories for purposes of research and discussion. Researchers and organizations working in drug abuse do not use a uniform set of subcategories, however. Common broad subcategories include three or four of the following: nitrous oxide (a gas used in anesthetic and aerosols), volatile nitrites, petroleum distillates, volatile solvents, gases, anesthetics, and aerosols.

Others place them in more specific, descriptive subcategories. The National Institute on Drug Abuse identifies six:

• industrial or household products (paint thinners or solvents, degreasers or cleaning fluids, gasoline, and volatile substances in glues)
• art and office supply solvents (correction fluids, glues, and solvents in markers)
• gases such as butane and chlorofluorocarbons used in household or commercial products (butane lighters, whipped cream dispensers, electronic contact cleaners, and refrigerant gases)
• household aerosol propellants (hair, cooking, lubricant, and fabric protector sprays)
• medical anesthetic gases (ether, chloroform, halothane, and nitrous oxide)
• aliphatic nitrites

However inhalants are categorized, the two most commonly abused types are solvents and gases.

A solvent is a substance that can dissolve another substance, and a volatile solvent is a liquid that vaporizes at room temperature. Volatile solvents include adhesives such as airplane glue and rubber cement; aerosols such as spray paint, hair spray, and air freshener; solvents such as nail polish remover, paint remover, and lighter fluid; and cleaners such as dry cleaning fluid, spot remover, and degreasers.

Gases include anesthesia used in medical procedures, as well as gases used in household or commercial products, such as butane lighters, propane tanks, whipped cream dispensers, and refrigerants.

CHEMICAL/ORGANIC COMPOSITION

No single chemical structure defines inhalants, because the term itself describes any vapor-producing volatile chemical that abusers sniff, huff, spray, or inhale to achieve intoxication. By nature, inhalants come in many forms—about 1,000 to 1,400 different products, according to different U.S. authorities. Also, some products are a mix of chemicals that, when combined, multiply and heighten the toxic impact.

Following are examples of such chemicals, by category, listed by the National Inhalant Prevention Coalition and Kaiser Permanente:

• Aerosols: Sprays containing propellants and solvents. In the United States, spray paints contain butane and propane (aliphatic hydrocarbons), fluorocarbon, hydrocarbons, and toluene; hair sprays and air fresheners contain butane, propane, and fluorocarbon; aerosol spray topical pain relievers and asthma sprays contain fluorocarbon.
• Anesthetics: Nitrous oxide (N₂O) or laughing gas, the most abused of the gases. Liquid anesthetic contains halothane and enflurane; local anesthetic contains ethyl chloride. Vegetable oil cooking spray and whipping cream cartridges also contain nitrous oxide.
• Cleaning agents: Dry cleaning fluid and spot removers contain tetrachloroethylene and trichloroethane; degreasers contain those ingredients as well as trichloroethylene and methylene chloride. Trichlorethylene and trichlorethane are also found in antifreeze, caulking compounds, and in some paints, glues, adhesives, and sealants.
• Solvents: Polish remover contains acetone; paint remover, paint thinner, and correction fluids contain toluene (an aromatic hydrocarbon), methylene chloride, and methanol; fuel gas contains butane; lighter fluid contains butane and isopropane; fire extinguishers contain bromochlorodifluoromethane.
• Nitrites: Room odorizers such as Locker Room, Rush, Poppers, Bolt, and Climax (also marketed as video head cleaner) contain amyl nitrite, butyl nitrite, and propyl nitrite.
• Freons: Halogenated hydrocarbons, refrigerants.
• Gasoline: A mixture of toluene and benzene and C6-C8 aliphatic.

INGESTION METHODS

Inhalants are so called because, almost exclusively, abusers breathe them into the nose or mouth. Some of the methods for accomplishing this pose additional dangers, such as unconsciousness, suffocation, and freezing of mouth or throat tissue, or vocal chords. Users may also incur injuries from falling, and may suffer sudden cardiac arrest. (Rarely, abusers mix inhalants into soft drinks and drink them.)

NIDA and the Partnership for a Drug-Free America describe several methods by which inhalants area consumed:

• Sniffing or snorting fumes from a container.
• Spraying aerosols directly into the nose or mouth.
• Bagging, which involves sniffing or inhaling fumes from substances sprayed or deposited inside a plastic or paper bag.
• Huffing, which involves soaking a cloth, sock, or roll of toilet paper with an inhalant, then stuffing that in the mouth.
• Inhaling from balloons filled with nitrous oxide.

Once inhaled, the chemicals move into the lungs; from there, they enter the bloodstream. The blood quickly carries the toxins to organs throughout the body, including the brain.

THERAPEUTIC USE

Most inhalants have no medical use. Exceptions are the anesthetic gases and amyl nitrite. Anesthetic gases slow the heart's pumping action, resulting in a drop in blood pressure. They also deaden pain and put surgery patients into an unconscious state. Amyl nitrite, a clear, yellowish liquid, relaxes the smooth muscle in the walls of the arteries. That relaxation dilates the blood vessels, reduces blood pressure, and increases the heart rate.

USAGE TRENDS

The Monitoring the Future study (MTF), funded by the National Institutes of Health's National Institute on Drug Abuse and conducted by the University of Michigan's Institute for Social Research since 1975, looks at lifetime, annual, and 30-day use of 13 categories of drugs, including inhalants. For the 2001 survey, more than 44,000 students filled out questionnaires in a nationally representative sample of eighth, tenth, and twelfth graders at private and public schools.

The 2001 MTF study found a continuation of the gradual decline in inhalant abuse that began in 1996 and 1997 among U.S. middle school and high school students. The study found a peak in inhalant use, for all grades, in 1995.

In the spring 2001 MTF study, 9.1% of eighth graders, 6.6% of tenth graders and 4.5% of twelfth graders reported using inhalants the previous year. In contrast, in 1997 11.8% of eighth graders, 8.7% of tenth graders, and 6.7% of twelfth graders reported using inhalants the previous year. In general, the appeal of inhalants appears to peak in middle school.

Lifetime use of inhalants, defined as whether U.S. students had used them at least once at some point in their lives, dropped from 21% of eighth graders in 1997 to 17.1% in 2001.

Paradoxically, fewer twelfth graders reported that they had used inhalants in the past than did eighth graders. Researchers are puzzled by the fact that, over the years, a lower percentage of high school seniors report that they've ever used inhalants than do middle-school students. The researcher say the conflicting information may be caused by the fact that older students do not recall everything they did when they were younger; and/or that chronic inhalant abusers drop out of school and thus no longer participate in the survey.

The Partnership for a Drug-Free America sponsored a smaller national survey, the 2000 Partnership Attitude Tracking Study, that included 7,290 teenagers in grades seven through 12. In the survey, 13% of students reported using inhalants in the previous year, compared with 11% in 1999. Twenty-one percent said they had tried inhalants at some point in their lives, and 78% percent of the teens said they recognized the deadly consequences of using inhalants. Earlier studies by the same organization found that teens saw dangers in regular use of inhalants, but not in occasional use.

Scope and severity

In looking at how inhalant abuse compares to other drug use, the MTF study found that among eighth graders, 9.1% reported they had used inhalant the previous year, while 41.9% used alcohol, 15.4% reported marijuana/hashish use; and 12.2% used cigarettes.

In its National Drug Threat Assessment 2002, the National Drug Intelligence Center reported that adolescents tend to initially experiment with four substances: alcohol, tobacco, inhalants, and marijuana.

The 2000 National Household Survey on Drug Abuse, a SAMHSA project, found that 8.9% of youths aged 12 to 17—about 2.1 million adolescents—had used inhalants at some time in their lives. In this same age group, 3.9% had used glue, shoe polish, or toluene; and3.3% reported using gasoline or lighter fluid.

Solvent abuse—particularly toluene-containing products such as gasoline and glue—is common around the world. NIDA considers it "an international public health concern," and notes that the problem is particularly severe in poor nations with high populations of homeless children. Some researchers have attributed the prevalence of glue sniffing in poverty-stricken countries to the fact that it offers children an escape from hunger pains and their desperate circumstances.

Glue sniffing exploded in Singapore between 1980 and 1991. The Central Narcotics Bureau of Singapore reported 24 cases of inhalent abuse in 1980. In 1985 the reported cases rose to 1,005. Recently, in South America, researchers found that almost a quarter of children of low-income families in Sao Paulo, Brazil, had inhaled a volatile substance at some time in their lives, and 4.9% had done so within the previous month. In Mexico, researchers who conducted a survey of street children found that 12% had started using glue regularly by the age of nine.

Researchers have found high inhalant use in other countries as well. An estimated 3.5% to 10% of children age 12 and under in the United Kingdom have abused volatile substances; and between 0.5% and 1% have become long-term users. In 1999, Australia's National Drug & Alcohol Centre secondary school survey of 25,480 students found that 32% of 12-year-old boys and 37% of 12-year-old girls reported that they had used an inhalant at some point.

Sniffing gasoline is also a serious problem among Native Americans in Canada, among young Aborigines in some rural desert communities in Australia, and among street children in Tanzania and Uganda.

The 1999 European School Survey Project on Alcohol and Other Drugs found the following rates of lifetime inhalant use reported by graduating high school students: Ireland, 22%; Greenland, 19%; Malta, 16%; United Kingdom, 15%; Slovenia, 14%; Greece, 14%; Croatia, 13%; Iceland, 11%; France, 11%; Lithuania, 10%; Hungary, 4%; Portugal, 3%; Bulgaria, 3%; and Romania, 2%.

Age, ethnic, and gender trends

Inhalant users typically fall into one of three groups: young experimenters who may use a variety of inhalants and some marijuana and alcohol; abusers who use multiple drugs, with inhalants as a backup to their drug of choice; and chronic adult users. While inhalant use tends to be at its highest during adolescence, some early abusers move from experimentation into regular, long-term use, and some continue to abuse the substances into their 50s and 60s. Those who continue using inhalants at later ages develop more severe social and psychological problems than do those who discontinue use after adolescence.

In a three-year study of inhalant abuse data from poison centers in 45 states, researchers found that inhalant abuse can begin early in childhood—in some reported cases, before the age of six—and peaks in early adolescence. The study, published in the August 2000 issue of the Journal of Toxicology, found that children under age 18 made up 47% of all inhalant abuse patients; and that 31% of all deaths related to inhalant use occurred in youths between the ages of 13 and 19.

Research on gender differences in use of inhalants have produced varying findings. In 1998, the National Household Survey on Drug Abuse found an even gender split in adolescents (ages 12–17) who experimented with inhalants. However, continued use was more common among older males; the rate of inhalant abuse by males 18 years to 25 years was twice that of their female peers.

Another study, reported by NIDA, found that boys abused inhalants more often than girls in grades four through six. Use evened out in the peak-use years of grades seven through nine; and returned to higher rates for males in grades 10 through 12.

Other researchers have found gender differences in the type of inhalant preferred. For instance, in a Virginia study published in the American Journal of Drug and Alcohol Abuse (October 1999), males were significantly more likely than females to abuse gasoline; and females were significantly more likely to abuse hair spray than their male age peers.

Some studies in North America have found the highest rate of inhalant abuse among white and Latino youths, and among Native American youths who live on reservations. The lowest rate of inhalant use is among African-American youths.

In two 1990s studies of high schools in Illinois, published in the November 2000 issue of the American Journal of Drug and Alcohol Abuse, researchers found that white and Hispanic teens from strong, two-parent families were less likely to abuse inhalants than those from single-parent families; and that Asian students whose academic performance was poor were more likely to use inhalants than "high-achievers" were.

Death resulting from inhalant use is more common in males. The Drug Abuse Warning Network (DAWN) monitors drug-related deaths as reported by medical examiners in 40 metropolitan areas. In 1999, medical examiners in these cities recorded 129 deaths from inhalants, a 25% increase over the 103 inhalant deaths recorded in 1998. Those who died in 1999 from inhalant use ranged from adolescents to adults age 55 and older, and were predominantly white.

From an socioeconomic perspective, inhalant abuse is most often associated with poverty, but there are abusers in all classes. Older inhalant users may develop abuse problems because they have access to volatile chemicals and anesthetics at the workplace.

The role of community and cultural influences on inhalant use remains uncertain. Some researchers attribute higher use rates among Latinos to poverty, lack of opportunity, and social problems, rather than ethnicity. Others have found traits that distinguish families with greater rates of inhalant abuse, regardless of economic status. Such families may have chaotic lifestyles and with multiple relationship difficulties and other problems. In other cases, the parents may have their own problems with drug and alcohol abuse, or may have either abused their children or lacked strong influence over them. Some parents do not discourage their children from using inhalants or do not disapprove of their children's peers who abuse the substances.

MENTAL EFFECTS

Inhalants deliver their mind-altering effects very quickly, satisfying the desires of users looking for instant gratification. The effects, depending on the inhalant, last from several seconds to several hours.

Abusers initially feel happy, giddy, excited, and uninhibited. After these immediate effects wear off, they may feel lightheaded, dizzy, drowsy, or agitated. They may hallucinate, have delusions, and/or experience a loss of sensation or of "feeling no pain." Concentrated doses can cause confusion and delirium.

Some users try to extend the brief high by sniffing repeatedly over a few hours, a practice that increases the risks of unconsciousness and death.

With time, regular abusers may experience personality and mental changes, including loss of short-term memory and difficulties with attention and learning. They can become apathetic and belligerent, and exhibit poor judgment in personal and work situations. Over the long term, inhalant abusers may display disorientation, inattentiveness, and irritability. They may also suffer from depression.

PHYSIOLOGICAL EFFECTS

The physical effects of inhalants vary because different inhalants combine different chemicals, and they produce different effects during and shortly after use.

Based on their studies of animals, scientists believe that, in general, when toxic vapors circulate to the brain, they depress the central nervous system. The action is similar to that of alcohol, sedatives, and anesthetics. Thus, many of the immediate physical changes inhalant users experience are similar to those caused by alcohol or anesthetics, including relaxation, slurred speech, slowed reflexes, lack of coordination, sleepiness, dizziness, headache, nausea, and vomiting. Abusers might also sneeze, cough, and drool.

Overdose can lead to a fast, irregular heartbeat, which can be fatal—a syndrome called sudden sniffing death.

Toluene, an ingredient in many abused inhalants, possibly works on dopamine, a brain chemical involved in the pleasure-producing effects of other abused substances. More research is needed to understand how inhalants produce their physiological effects.

Nitrites, used to enhance sexual experiences, are in a different category in terms of their effects. When inhaled, nitrates dilate the blood vessels and speed the heartbeat. As a result, abusers feel warm and excited for several minutes. They may also become flushed and dizzy, and may develop a headache.

Harmful side effects

The toxic chemicals in inhalants are capable of damaging many different organs and body systems, including the nervous system (brain, spinal cord, and nerves), heart, lungs, circulatory system, liver, kidneys, and the senses of smell, sight, and hearing. The young age of most abusers increases the potential for damage, because their bodies have not fully matured.

Trichloroethylene, an ingredient in spray paints and correction fluid, can damage the liver. Nitrites and methylene chloride (in paint thinner) reduce the blood's ability to carry proper amounts of oxygen. Inhaled spray paint can damage the lungs. Regular users of nitrous oxide and hexane (an ingredient in some glues and fuels) damage their nervous systems, resulting in numbness, tingling, or paralysis. Toluene hinders the kidneys' ability to regulate the amount of acid in the blood. (When the abuse stops, the kidneys go back to properly controlling acid levels, but the user may later develop kidney stones.) Trichloroethylene, a chemical in spot removers and degreasers, can damage hearing, vision, and the liver. Toluene affects reproduction, and may cause changes in chromosomes, abnormalities during pregnancy, and premature births. An overdose of amyl nitrite can be fatal.

Other side effects of inhalant use include persistent headaches, appetite loss, nosebleeds (sometimes severe enough to require hospitalization), and skin rashes (from contact with glue). Long-term inhalant abusers may lose weight, muscle tone and strength, and coordination.

Inhalants cross the placenta and are dangerous to the developing fetus. Infants born to solvent abusers suffer neonatal (newborn) inhalant withdrawal: high-pitched, extreme crying; poor sleeping and eating; quivering and trembling; and rigid, tense muscles. Researchers do not know if abnormalities that these infants develop are due to inhalants or another cause, such as alcohol. Studies of animals indicate that toluene causes low birth weight, skeletal abnormalities, and development delays.

Long-term health effects

Long-term, heavy use of inhalants damages the brain and the network of nerves that connects the brain and spinal cord to other organs. Research already conducted is inadequate, however, to determine the level of damage caused by relatively low levels of inhalant use. There also is insufficient information on the extent to which damage is reversible once a person stops using the substances.

Most damage to the nervous system develops after the abuse has continued two or three times a week for at least six months; but any amount of solvent abuse can break down nerve fibers.

Because different inhalants damage different parts of the brain and nervous system, the resulting problems depend on which areas were affected. If the frontal cortex is affected, problem-solving and advance-planning skills are impaired. The abuser may lose physical coordination and speed if the cerebellum is damaged. Oxygen deprivation in the hippocampus causes problems with learning new information or remembering familiar things. Damage to the myelin sheath (a protective coating on nerve cells) disrupts the nerves' ability to send and receive the messages that enable the body to think and act.

Health effects from inhalants range from mild to severe. A distinction between harmful side effects and long-term effects has not been fully determined. "Although some inhalant-induced damage to the nervous and other organ systems may be at least partially reversible when inhalant abuse is stopped, many syndromes caused by repeated or prolonged abuse are irreversible," according to the NIDA research report on inhalants, which was updated in February 2002.

NIDA's list of irreversible effects include hearing loss, limb spasms, brain damage, and bone marrow damage. Serious but potentially reversible effects include liver and kidney damage, and depletion of oxygen from the blood.

Nitrites carry special risks, even with modest use. Based on their research with animals, scientists suspect that nitrite abuse reduces the number of cells in the immune system. This possibly hinders the body's efforts to fight infectious diseases and resist the growth of tumors.

Death is also a possible consequence of inhalant abuse, because the chemicals displace oxygen, leading to an increased risk of sudden sniffing death. Users also die from asphyxiation (from inhaling repeatedly, which leaves the lungs full of chemicals instead of oxygen), suffocation (from blocking air to the lungs while inhaling fumes from a plastic bag over the head), choking (from inhaling and choking on vomit), and from a variety of accidental injuries caused by mental and physical effects of inhalants (car wrecks, drowning, falls, burns).

REACTIONS WITH OTHER DRUGS OR SUBSTANCES

Inhalants are not usually used with another illicit substance, though early users of inhalants have, on later surveys, reported early use (before age 18) of other drugs as well: marijuana, cocaine, amphetamines, and hallucinogens. Because some inhalants are flammable, this adds the additional health danger of fire and burns if someone near the abuser lights up to smoke tobacco or marijuana.

When users do combine inhalants with other drugs, the effects increase the health risks. Alcohol slows down the metabolism of toluene, thus raising its concentration in the blood. Cocaine can boost the chance of fatal irregular heart rhythms. Use of all of these substances, alone or in combination, increases the risk of dangerous behaviors.

TREATMENT AND REHABILITATION

Despite the extent of inhalant abuse and its potential for destroying mental and physical functions, little is known about effective behavior modification or drug-abuse prevention approaches to treating inhalant abusers. Inhalant abusers are often excluded from more general studies on drug abuse.

Relapse and treatment failure rates are high among inhalant abusers. Some professionals believe that programs specific to inhalant abuse, perhaps led by recovering abusers, are critical to improving treatment success. Few such programs exist. Indeed, some general treatment programs exclude inhalant abusers because of the difficulties in successfully treating them. The National Inhalant Prevention Coalition helps callers find centers that treat inhalant abuse.

As of 2002, inhalant abusers are mostly treated in the same programs that address addiction to other substances. The programs use the same approaches that are effective with other drug problems. Clinicians start by taking a history of the patient. That includes conducting a physical exam, screening for organ damage, and taking a detailed history of the length, type, and frequency of abuse. Building self-esteem and self-confidence, and strengthening ethnic identity, appear to help inhalant abusers recover, according to studies published in the 1970s.

When the patient is a teenager or younger, the treatment center conducts a family assessment. Treatment counselors attempt to assess parents' problems with drugs or their general mental health. The goals are to spot problems within the family and begin addressing them. The process includes identifying what is stressing users and teaching them better coping skills; treating any accompanying psychiatric conditions or additional addictions; and encouraging the child to engage in healthy friendships and stay away from peers who abuse inhalants.

Inhalants take a toll on the users' thinking skills, which can complicate treatment. Some patients need extra neurological and cognitive testing so that treatment can be properly tailored to their needs.

The toxic chemicals in inhalants are stored in fatty tissue in the body for weeks. Thus, when long-term abusers attempt to quit, they may develop withdrawal symptoms several hours to a few days afterward. The Office of National Drug Control Policy and the American Academy of Pediatrics list these common withdrawal symptoms: hand tremors, excessive sweating, constant headache, rapid pulse, insomnia, nausea, vomiting, physical agitation, anxiety, hallucinations, and grand mal seizures.

Much remains unknown about the physiology of withdrawal from various subcategories of inhalants and the best ways to address withdrawal symptoms. In early 2002, the National Institute on Drug Abuse, which had not funded a study specifically looking at treatment for inhalant abusers, was actively encouraging researchers to submit proposals in this area.

Long-term treatment, as long as two years, has yielded the best results for inhalant abusers. The after-care must continue outside the facility and into the community to be effective. Research shows that recovery is helped by factors such as parent groups who patrol inhalant abuse hot spots, and communities that offer structured recreational or other programs for youths to fill the time they previously spent sniffing or huffing.

PERSONAL AND SOCIAL CONSEQUENCES

Because many abusers begin using inhalants when they are young, they do not engage in the normal process of social, personal, and physical development during adolescence. This handicaps their physical and emotional maturity.

Moreover, the side effects of inhalants are a bad match for driving a vehicle, operating machinery, absorbing information in a classroom, offering stable friendship, participating positively in a family, or tackling any task with energy, focus, and efficiency.

Regular inhalant abusers perform poorly in school. In general, they earn low grades, score poorly on intelligence tests, experience problems with short-term memory, and have a weak ability to form abstract thoughts and exercise sound judgment. They also have a greater likelihood of developing attention deficit disorder. They tend to be absent from school a great deal, and drop out of school more often than nonusers do.

Psychological studies have shown that inhalant abusers are generally apathetic and have a negative view of the future. They have a greater likelihood of developing emotional problems, particularly anxiety, depression, and anger. They are more likely to break the law, particularly by engaging in theft and burglary, than do users of other drugs. They also tend to be disruptive, deviant, or delinquent.

Some of these problems may spring from the inhalant abuse; others may have developed before the abuse began, inclining the users to seek an escape from reality or their problems.

LEGAL CONSEQUENCES

The estimated 1,000 to 1,400 products considered to be inhalants are legal products and are not regulated under the federal Controlled Substances Act. However, the National Conference on State Legislatures reports that, as of June 2000, 38 states had enacted laws to address the issues of minors' use of inhalants. In various ways, the laws attempt to prevent the sale, use, and distribution to minors of certain products that are commonly abused.

California, for instance, prohibits the sale, distribution, or dispensation to a minor of toluene, materials containing toluene, and nitrous oxide. Minors are also forbidden to possess these substances. Louisiana prohibits the sale, transfer, or possession of model glue and inhalable toluene substances to minors. In Ohio, it is illegal to inhale certain compounds for intoxication—a common, general prohibition other states have enacted.

Some states draw their prohibitions more narrowly. New Jersey, for instance, prohibits selling or offering to sell minors products containing chlorofluorocarbon that is used in refrigerant.

Some states regulate inhalant sales tightly at the retail level. Minnesota, for instance, requires businesses to post signs stating the illegality of selling butane or butane lighters to minors. Minnesota also prohibits selling general inhalable compounds to minors, and it prohibits minors'use and possession of them for intoxification.

In Massachusetts, retailers must ask minors for identification before selling them glue or cement that contains a solvent that can release toxic vapors. Also, the products must contain oil of mustard or a similar deterrent against inhalation. Young Massachusetts inhalant purchasers must also legibly write their name and address in a bound register, which the retailer must make available to police and keep for at least six months after the final entry.

Some other governments take a similar approach to controlling access. Great Britain's Intoxicating Substances (Supply) Act of 1985 made it an offense to supply a product that will be abused. The Cigarette Lighter Refill (safety) Regulations of 1999 govern sale of purified liquefied petroleum gas, mainly butane, the sub-stance most often involved in inhalant fatalities in the United Kingdom. It is illegal to sell this type of cigarette lighter refill to anyone under age 18.

Despite the laws, inhalant abuse remains a major health problem. As the American Academy of Pediatrics stated in a 2000 paper on preventing inhalant abuse, "... since inhalants are legal and kids can get them from so many different ways, it is not possible to make inhalants entirely off limits."

See also Amyl nitrite; Nitrous oxide

RESOURCES

Books

Glowa, John A., and Solomon H. Snyder. Inhalants: The Toxic Fumes. Broomall, PA: Chelsea House Publishers, 1991.

Periodicals

Bykowski, Mike. "Sniff Out Inhalant Abuse Among Young Patients." Family Practice News (November 1, 1999).

Meyerhoff, Michael. "Facts About Inhalant Abuse." Pediatrics for Parents (July 2001).

Stapleton, Stephanie. "Is Your Patient (or Child) Abusing Inhalants?" American Medical News (April 9, 2001).

Other

"Common Inhalants." American Academy of Pediatrics Medical Library. 2000 (April 6, 2002). http://www.medem.com/search/article_display.cfm?path=n:&mstr=/ZZZDARS2B7C.html&soc =AAP&srch_typ=NAV_SERCH.

"Effects of Inhalants." American Academy of Pediatrics Medical Library. 2000 (April 6, 2002). http://www.medem.com/search/article_display.cfm?path=n:&mstr=/ZZZ5B6O2B7C.html&soc= AAP&srch_typ=NAV_SERCH.

"Mind Over Matter: The Brain's Response to Inhalants." <http://165.112.78.61/MOM/IN/MOMIN1.html>.

"Preventing Inhalant Abuse." American Academy of Pediatrics Medical Library. 2000 (April 6, 2002). http://www.medem.com/search/article_display.cfm?path=n:&mstr=/ZZZ2TQUQA7C. html&soc=AAP&srch_typ=NAV_SERCH.

U.S. Department of Health and Human Services. National Institutes of Health. Inhalant Abuse. National Institute on Drug Abuse Research Report Series. Revised July 2000. NIH Publication Number 00-3818.

Organizations

Monitoring the Future Study, Survey Research Center, Institute for Social Research at the University of Michigan, P.O. Box 1248, Ann Arbor, MI, USA, 48106, (734) 764-8365, (734) 647-4575, MTFinfo@isr.umich.edu.webmaster@health.org, <http://www.monitoringthefuture.org>.

National Clearinghouse for Alcohol and Drug Information (NCADI), P.O. Box 2345, Rockville, MD, USA, 20847-2345,(800) 729-6686, webmaster@health.org, <http://www.health.org>.

National Drug Intelligence Center (NDIC), 319 Washington Street, 5th Floor, Johnstown, PA, USA, 15901-1622, (814) 532-4601, (814) 532-4690, cmbwebmgr@ndic.osis.gov, <http://www.usdoj.gov/ndic/>.

National Inhalant Prevention Coalition, 2904 Kerbey Lane, Austin, TX, USA, 78703, (512) 480-8953, (512) 477-3932, (800) 269-4237, nipc@io.com, <http://www.inhalants.org>.

National Institute on Drug Abuse, National Institutes of Health (NIH), 6001 Executive Boulevard, Room 5213, Bethesda, MD, USA, 20892-9561, (301) 443-1124, (888) 644-6432, information@lists.nida.nih.gov, <http://www.nida.nih.gov>.

Substance Abuse and Mental Health Services Administration (SAMSHA)/Center for Substance Abuse Treatment (CSAT), 5600 Fishers Lane, Rockville, MD, USA, 20857, (301) 443-8956, info@samhsa.gov, <http://www.samhsa.gov>.

Janet D. Filips