Page 212 - Understanding Psychology

marijuana: the dried leaves and flowers of Indian hemp (Cannabis sativa) that produce an altered state of conscious- ness when smoked or ingested
Like hormones, drugs are carried by the blood and taken up in target tissues in various parts of the body. Unlike hormones, though, drugs are taken into the body from the outside. People introduce drugs into their systems through routes that bring the drugs into contact with capillaries (the smallest blood vessels). From there, drugs are gradually absorbed into the blood. Then drug molecules act like neurotransmitters and hook onto the ends of nerve cells (neurons) and send out their own chemical messages. For example, alcohol molecules may tell a nerve cell not to fire. As more and more cells cease firing, the alcohol user becomes slower and may eventually lose consciousness. LSD molecules may cause circuits in different areas of the brain to start firing together instead of separately, resulting in hallucinations.
MARIJUANA
Used as an intoxicant among Eastern cultures for centuries, mari- juana is legally and morally acceptable in some societies, whereas alco- hol is not. The sale and possession of marijuana is against the law in most states. Before 1960, marijuana use in the United States was common only
HOW DRUGS WORK
Figure 7.4 Some Psychoactive Drugs
Psychoactive drugs influence how we sense and perceive things and modify our moods, feelings, emotions, and thoughts. What effects do depressants produce?
Drug Category Effects on Behavior
Depressants
Alcohol
Tranquilizers
Barbiturates, benzodiazepines (Valium, Xanax)
Opiates
Morphine, heroin
Stimulants
Caffeine, amphetamines, cocaine
Mixed Stimulant-Depressants
Nicotine
Distortion of Experience
Marijuana (THC)
Hallucinogens
Relaxant; relieve inhibitions; impair memory and judgment Relieve anxiety; relax muscles; induce sleep
Decrease pain; decrease attention to real world; unpleasant withdrawal effects as drug’s effect wears off
Increase energy, alertness
Stimulate brain activity, but most smokers say cigarettes relax them
Intensifies sensory experiences; distorts perception of time;
can relieve glaucoma, nausea; sometimes impairs learning, memory
Cause hallucinations, sensory distortions, and occasionally panic
LSD, mescaline
198 Chapter 7 / Altered States of Consciousness