I'm not worried about becoming an addict. Are there any other risks of occasional drug use?
What exactly is methamphetamine, and why is it such a problem in the United States ?
Alcohol seems to affect me differently than it affects some of my friends. Why is this?
Can a person drink more "light" beer than regular beer without becoming as intoxicated?
What are the causes and effects of a hangover?
Are men or women more likely to be problem drinkers or have problems associated with alcohol use?
Does smoking in the movies influence people's smoking habits?
What are some of the additives in cigarettes?
What effect does menthol have in cigarettes?

Yes. Dependence is not the only serious potential consequence of drug use; these additional risks include the following:

• Intoxication: People who are under the influence of drugs—intoxicated—may act in uncharacteristic and unsafe ways because both their physical and mental functioning are impaired. They are more likely to be injured from a variety of causes, including falls, drowning, and automobile crashes; to engage in unsafe sex, increasing their risk for STDs and unintended pregnancy; and to be involved in incidents of aggression and violence, including sexual assault.
• Unintended side effects: Psychoactive drugs have many physical and psychological effects beyond the alteration of consciousness. These effects range from nausea and constipation to paranoia, depression, and heart failure. Some drugs also carry the risk of potentially fatal overdose.
• Unknown drug constituents: There is no quality control in the illegal drug market, so the composition, dosage, and toxicity of street drugs is highly variable. Studies of samples indicate that many street drugs don't contain their promised primary ingredient; in some cases, a drug may be present in unsafe dosages or mixed with other drugs to boost the effects. Careless manufacturing practices can result in the presence of toxic contaminants.
• Risks associated with injection drug use: Many injection drug users (IDUs) share or reuse needles, syringes, and other injection equipment, which can easily become contaminated with the user's blood. Small amounts of blood can carry enough human immunodeficiency virus (HIV) and hepatitis C virus (HCV) to be infectious, and injection drug use accounts for about 25% of all HIV/AIDS cases and about 60% of all hepatitis C cases reported in the United States. It's estimated that about 15% of current IDUs are infected with HIV and as many as 95% may carry HCV. Unsterile injection practices can cause skin and soft tissue infections, which can progress to gangrene and be fatal if untreated. Other risks include endocarditis (infection of the heart valves), tuberculosis, and tetanus. The surest way to prevent diseases related to injection drug use is never to inject drugs. Those who do inject drugs should use a new needle and syringe with each injection and should use sterile water and other equipment to prepare drugs. Bleach or boiling water may kill some viruses and bacteria, but they are not foolproof sterilization methods. Many viruses can survive in a syringe for a month or more
• Legal consequences: Many psychoactive drugs are illegal, so using them can result in large fines and/or imprisonment. The FBI reports nearly 1.7 million drug-related arrests each year. Possession of marijuana, heroin, or cocaine are the most commonly reported violation.

As its name suggests, methamphetamine (meth) is similar to the stimulant amphetamine. Meth, however, is more addictive and dangerous than most forms of amphetamine because it is more toxic and its effects last longer. Methamphetamine is highly addictive; many casual users rapidly become regular users.

          Methamphetamine has several street names, including "speed" and "chalk." One form of meth—methamphetamine hydrochloride—is known as "ice," "crystal," or "glass." Meth is available in powder and crystal form, and can be swallowed, snorted, smoked, or injected. Once taken, the drug causes the brain to release high amounts of dopamine, a key neurotransmitter.

          By stimulating dopamine activity in the brain, meth increases the user's ability to stay awake and perform physical activity. Many college students report using meth to help them stay awake for studying and partying. Meth use has been documented among some types of workers, such as long-haul truck drivers, who must work for long periods without stopping to rest. Meth's other short-term effects can include euphoria, rapid breathing, increased body temperature (hyperthermia), insomnia, tremors, anxiety, and convulsions.

          With long-term use, however, meth's effects can be devastating. Severe weight loss, heart attack, stroke, hallucinations, violence, paranoia, and psychotic behavior have all been linked to meth addiction. Brain damage similar to that found in Parkinson's disease and Alzheimer's disease has been reported in long-term meth users. Meth use causes extensive tooth decay and tooth loss, a condition referred to as "meth mouth." The drug takes a severe toll on the user's heart, increasing heart rate and blood pressure, damaging blood vessels, and causing irregular heartbeat. Such cardiovascular damage can be fatal.

          The National Survey on Drug Use and Health reported that more than half a million Americans aged 12 and older were current users of methamphetamine in 2005. The researchers warned that this number is probably an underestimate due to survey wording; other estimates put the number of regular meth users closer to 1.5 million. The highest rates of use are among young adults aged 18-25.

          Although methamphetamine is often called "poor man's cocaine," its users are not all poor or poorly educated; rather, they span the socioeconomic spectrum. Like many lab-produced drugs, meth began its spread in poor inner-city areas, where it became popular because it was relatively inexpensive and offered a quick yet long-lasting high. But meth rapidly spread to the suburbs and into rural areas, affecting people of all ages and walks of life. Meth addicts are rich and poor, from all races, and include parents as well as children.

          Methamphetamine is now found in all 50 states, and many drug enforcement and government officials say it is the number-one drug problem in America today. In 2005, 58% of law enforcement agencies reported that methamphetamine was their biggest drug-related concern.

          Along with the physical problems suffered by meth users, the drug has led to a growing array of social and emotional problems. For example, because meth diminishes the user's judgment, many meth addicts engage in unsafe sex when they're high—often with injection drug users. As a result, meth users face an increased risk of infection from a variety of transmittable diseases, especially HIV and hepatitis C. Meth is also associated with domestic violence and family breakdown.

          Another problem unique to meth is its do-it-yourself appeal to users and dealers. The drug is relatively easy to make, using commonly available chemicals, and clandestine meth labs in residential living rooms and basements have sprung up across the country. One of the chemicals used in making meth is pseudoephedrine, a drug found in products used to relieve nasal or sinus congestion, such as Sudafed and other cold and allergy medications. To limit access to this drug, Congress passed the Combat Methamphetamine Epidemic Act of 2005 as part of the Patriot Act, requiring behind-the-counter sale of products containing pseudoephedrine and two other drugs used to make meth. Quantities that can be purchased are limited, and customers must show a photo ID and sign a logbook. Cold and allergy products containing ingredients not used in meth production are still available on the shelves, such as Sudafed PE.

          Meth production is also very dangerous. The use of caustic and highly explosive chemicals puts meth "cooks" at risk for injury and death from explosion and fire.

At this time, there are few treatment options for meth addiction. Cognitive behavioral therapy is widely viewed as the best approach; therapy helps users identify the root causes of their addiction and teaches them skills needed to effectively quit using the drug. In some cases, antidepressants or antianxiety medications are prescribed, but there currently is no single effective pharmacological treatment for methamphetamine addiction. In studies, the drug Prometa has been effective in helping meth addicts break their addiction. Further studies are underway.

If you react differently to alcohol than some of your friends do, you may be noticing genetic differences in alcohol metabolism that are associated with ethnicity. Alcohol is metabolized mainly in the liver, where it is broken down by an enzyme called alcohol dehydrogenase, producing a by-product called acetaldehyde. Acetaldehyde is responsible for many of the unpleasant effects of alcohol abuse. Another enzyme, acetaldehyde dehydrogenase, breaks this product down further.

          Some people, including many of Asian descent or certain Jewish population groups, have genes that cause them to produce somewhat different forms of the two enzymes that metabolize alcohol. The result is high concentrations of acetaldehyde in the brain and other tissues, producing a host of unpleasant symptoms. When people with these enzymes drink alcohol, they experience a physiological reaction referred to as flushing syndrome. Their skin feels hot; their heart and respiration rates increase; and they may get a headache, vomit, or break out in hives. Drinking makes some people so uncomfortable that it's unlikely they could ever become addicted to alcohol.

          The body's response to acetaldehyde is the basis for treating alcohol abuse with the drug disulfiram (Antabuse), which inhibits the action of acetaldehyde dehydrogenase. When a person taking disulfiram ingests alcohol, acetaldehyde levels increase rapidly, and he or she develops an intense flushing reaction along with weakness, nausea, vomiting, and other disagreeable symptoms.

          How people behave in relation to alcohol is influenced in complex ways by many factors, including social and cultural ones. But in this case, at least, individual choices and behavior are strongly influenced by a specific genetic characteristic.

No. The "light" in light beer refers to calories; a light beer typically has close to the same alcohol content as a regular beer and about 100 calories. People who choose to drink alcohol should remember to count the calories in alcoholic beverages toward their total daily calorie intake to avoid unintentional weight gain. Alcohol provides 7 calories per gram, and the alcohol in one drink (14-17 grams) supplies about 100-120 calories. Most alcoholic beverages also contain some carbohydrate, so, for example, one beer provides about 150 total calories.

A hangover is probably caused by a combination of the toxic products of alcohol breakdown, dehydration, and hormonal effects. The symptoms include headache, shakiness, nausea, diarrhea, fatigue, and impaired mental functioning. Hangovers cost the U.S. economy billions of dollars each year because of absenteeism and poor job performance. Hangovers represent a substantial portion of the money lost to society as a result of alcohol use. But hangovers can have more serious effects as well: During a hangover, heart rate and blood pressure increase, making some individuals more vulnerable to heart attacks. Electroencephalography (brain wave measurement) shows diffuse slowing of brain waves for up to 16 hours after BAC drops to zero. Studies of pilots, drivers, and skiers all indicate that coordination and cognition are impaired in a person with a hangover, increasing the risk of injury. If you get a hangover, remember that your ability to drive is definitely impaired, even after your BAC has returned to zero.

Men are more likely than women to drink alcohol, to abuse alcohol, and to have alcohol dependency. Men account for the majority of alcohol-related deaths and injuries in the United States, and the majority of these occur in men age 35 years and younger. Most alcohol-related deaths and injuries among men result from acute conditions related to intoxication, such as motor vehicle crashes, falls, drowning, suicide, and homicide.

          A variety of factors contributes to higher rates of alcohol use and abuse among men. Traditional or stereotypic gender roles and ideas regarding masculinity and drinking behavior may promote excessive alcohol consumption among men. Young men in particular are also more likely to engage in all types of risky health behaviors. Men drive more miles, drive more dangerously, and are more likely to drive while intoxicated. Males tend to have greater access to firearms, contributing to their increased rates of suicide and homicide. Men may also be more likely than women to use alcohol to cope with stress and other life challenges.

          Women are not immune to alcohol problems, however, and rates of alcohol abuse and dependence among women have increased in the past decade. Whether a woman is a "social drinker," a binge drinker, or a heavy daily user, the impact of alcohol on her will be different from and generally greater than the impact of comparable use on a man. And because of the social stigma attached to problem drinking, particularly among women, women are less likely to seek early treatment.

          Women become intoxicated at lower doses of alcohol than men, and they tend to experience the adverse physical effects of chronic drinking sooner and at lower levels of alcohol consumption than men. Female alcoholics have higher death rates than male alcoholics, including death rates from cirrhosis. They develop alcohol liver disease and alcohol-related brain damage after a comparatively shorter period of heavy drinking and a lower level of drinking than men. Other alcohol-related health problems are unique to women, including an increased risk of breast cancer, menstrual disorders, infertility, and, in pregnant women, giving birth to a child with fetal alcohol syndrome (FAS).

          Both men and women are likely to be the perpetrator or victim of a crime when they have been drinking. Sexual assaults of all types, and date rape in particular, are more likely to occur when people are intoxicated. Alcohol use also makes men and women much less likely to practice safer sex, leaving them vulnerable to significant and lasting health problems as the result of sexually transmitted diseases and, for women, unintended pregnancy.

Studies of adolescents have consistently found a strong association between seeing tobacco use in films and trying cigarettes. Adolescents who see more smoking in films or whose favorite movie stars frequently use tobacco onscreen have more positive attitudes about smoking and are as much as three times more likely to have tried smoking than teens with less exposure to films. Teens may be particularly sensitive to onscreen portrayals of smoking because they are in the process of developing adult identities; during this period, they may try out different personas, including those of their favorite movie stars.

          Tobacco companies agreed to end paid product placement in movies as part of the 1998 settlement deal; a voluntary ban had been in effect since 1990. This ban does not appear to be having the intended effect, however. Researchers have found that smoking in movies has actually increased significantly since 1990, to levels not seen since 1960. In the 2 years following the settlement deal, smoking in PG-13 movies increased by 50%. Half the tobacco shots in the top movies from 2002 to 2003 were in G, PG, and PG-13 movies.

          The portrayal of smoking in films doesn't reflect U.S. patterns of tobacco use. The prevalence of smoking among lead characters is three to four times that among comparable Americans. Films typically show the smoker as white, male, well educated, successful, and attractive. In reality, smokers tend to be poor and to have less education. In the top-grossing films in 2002-2003, smoking was portrayed in more than 73% of the films, including 82% of PG-13 films; smoking was often shown positively as a means to relieve tension or as something to do while socializing. Negative consequences resulting from tobacco use were depicted for only 3% of the major characters who used tobacco. By showing smoking in an unrealistically positive light, films may be acting as advertisement.

          Some groups equate seeing a favorite actor smoke onscreen with now-banned celebrity television advertisements for cigarettes. They suggest an automatic R rating for any film that shows tobacco use, equating smoking with violence, strong language, sexuality, and nudity in determining a film's rating. The debate over the prevalence and effects of smoking is likely to continue.

Tobacco manufacturers use additives to manipulate the taste and effects of cigarettes and other tobacco products. Nearly 600 chemicals, approved as safe when used food additives, are used in manufacturing cigarettes. However, although these ingredients are regarded as safe when ingested in foods, some may form dangerous compounds when heated or burned.

          Additives account for roughly 10%, by weight, of a cigarette, and include sugars and other flavoring agents, humectants (compounds that keep tobacco from drying out), and chemicals that enhance the addictive properties of nicotine. The added sugars—including licorice, cocoa, and honey—have a dual role. As flavor enhancers, sugars mask the harsh bitter taste of tobacco, making it possible for smokers, particularly first-time smokers, to inhale larger volumes of smoke and therefore absorb more nicotine. When they burn, sugars produce acetaldehyde, a chemical that enhances the addictive effect of nicotine and is also a carcinogen. Other flavor components, for example the theobromine found in cocoa and glycyrrhizin in licorice, share one of the properties of menthol—they act as bronchodilators, opening the lungs' airways and making it easier for nicotine to get into the bloodstream.

          Ammonia plays a complex role in tobacco products, but its chief purpose is to boost the amount of addictive nicotine delivered by cigarettes. Ammonia reduces the acidity of tobacco smoke and releases nicotine in the form of a base (alkaline) rather than a salt (acid) bound to other acid components of smoke. As a free base, nicotine is more readily absorbed into the blood.

          Some tobacco additives are intended to make sidestream smoke (the uninhaled smoke from a burning cigarette) less obvious and objectionable. Additives such as potassium citrate, aluminum and other metal hydroxides, and clay are added to cigarette wrappers to convert particulate ash into an invisible gas with less irritating odor than a conventional paper wrapper. These additives serve no purpose in making cigarettes more desirable and addicting to the smoker; instead, they are intended to reduce social pressures from nonsmokers.

Menthol has an anesthetizing effect and may allow smokers to inhale more deeply and to hold smoke in their lungs for a longer period—both of which have a negative impact on health. About 70% of African American smokers smoke menthol cigarettes, as compared to 30% of white smokers. Studies have found that blacks absorb more nicotine than other groups and metabolize it more slowly; they also have lower rates of successful quitting. Menthol may be partly responsible for these trends.