Cannabis

Use of cannabis may impair or reduce short-term memory and comprehension, alter sense of time, and reduce ability to perform tasks requiring concentration and coordination, such as driving a car. Motivation and cognition may be altered, making the acquisition of new information difficult. Marijuana can also produce paranoia and psychosis.

Because users often inhale the unfiltered smoke deeply and then hold it in their lungs as long as possible, marijuana is damaging to the lungs and pulmonary system. Marijuana smoke contains more cancer-causing agents than tobacco smoke. Long-term users of cannabis may develop psychological dependence and require more of the drug to get the same effect.

Deeply inhaling the vapors, or using large amounts over a short time, may result in disorientation, violent behavior, unconsciousness, or death. High concentrations of inhalants can cause suffocation by displacing the oxygen in the lungs or by depressing the central nervous system to the point that breathing stops.

Long-term use can cause weight loss, fatigue, electrolyte imbalance, and muscle fatigue. Repeated sniffing of concentrated vapors over time can permanently damage the nervous system.

Cocaine

Crack or freebase rock is extremely addictive, and its effects are felt within 10 seconds. The physical effects include dilated pupils, increased pulse rate, elevated blood pressure, insomnia, loss of appetite, tactile hallucinations, paranoia, and seizure. The use of cocaine can cause death by cardiac arrest or respiratory failure.

Other Stimulants

In addition to the physical effects, users report feeling restless, anxious, and moody. Higher doses intensify the effects. Persons who use larger amounts of amphetamines over a long period of time can develop an amphetamine psychosis that includes hallucinations, delusions, and paranoia. These symptoms usually disappear when drug use ceases.

Depressants

Regular use of depressants over time can result in physical and psychological addiction. People who suddenly stop taking large doses can experience withdrawal symptoms, including anxiety, insomnia, tremors, delirium, convulsions, and death. Babies born to mothers who abuse depressants may also be physically dependent on the drugs and show withdrawal symptoms shortly after they are born. Birth defects and behavioral problems also may result.

Lysergic acid (LSD), mescaline, and psilocybin cause illusions and hallucinations. The physical effects may include dilated pupils, elevated body temperature, increased heart rate and blood pressure, loss of appetite, sleeplessness, and tremors. The user may experience panic, confusion, suspicion, anxiety, and loss of control.

Tolerance to narcotics develops rapidly and dependence is likely. The use of contaminated syringes may result in disease such as AIDS, endocarditic, and hepatitis. Addiction in pregnant women can lead to premature, stillborn, or addicted infants who experience severe withdrawal symptoms.

The narcotic analogs can cause symptoms such as those seen in Parkinson's disease: uncontrollable tremors, drooling, impaired speech, paralysis, and irreversible brain damage. Analogs of amphetamines and methamphetamines cause nausea, blurred vision, chills or sweating, and faintness. Psychological effects include anxiety, depression, and paranoia. As little as one dose can cause brain damage. The analogs of phencyclidine cause illusions, hallucinations, and impaired perception.

Taken in combination with a program of muscle-building exercise and diet, steroids may contribute to increases in body weight and muscular strength. Steroid users subject themselves to more than 70 side effects ranging in severity from liver cancer to acne and including psychological as well as physical reactions. The liver and cardiovascular systems are most seriously affected by steroid use. In males, use can cause withered testicles, sterility, and impotence. In females, irreversible masculine traits can develop along with breast reduction and sterility. Psychological effects in both sexes include very aggressive behavior known as "roid rage" and depression. While some side effects appear quickly, others, such as heart attacks and strokes, may not show up for years.

Signs of steroid use include quick weight and muscle gains (when used in a weight training program); aggressiveness and combativeness; jaundice; purple or red spots on the body; swelling of feet and lower legs; trembling; unexplained darkening of the skin; and persistent unpleasant breath odor.

Continued use of alcohol can lead to dependence. Sudden cessation of alcohol intake is likely to produce withdrawal symptoms, including severe anxiety, tremors, hallucinations, and convulsions. Long-term effects of consuming large quantities of alcohol, especially when combined with poor nutrition, can lead to permanent damage to vital organs such as the brain and the liver. In addition, mothers who drink alcohol during pregnancy may give birth to infants with fetal alcohol syndrome. These infants may suffer from mental retardation and other irreversible physical abnormalities. In addition, research indicates that children of alcoholic parents are at greater risk than other children of becoming alcoholics.

Smoking during pregnancy also poses serious risks. Spontaneous abortion, pre-term birth, low birth weights, and fetal and infant deaths are all more likely to occur when the pregnant woman is a smoker.

Cigarette smoke contains some 4,000 chemicals, several of which are known carcinogens. Perhaps the most dangerous substance in tobacco smoke is nicotine. Nicotine is the substance that reinforces and strengthens the desire to smoke. Because nicotine is highly addictive, addicts find it very difficult to stop smoking. Of 1,000 typical smokers, fewer than 20 percent succeed in stopping on the first try.