4.18 : 精神活性药物概述

Psychoactive drugs act on the nervous system and brain functions and alter consciousness, impacting mood, perception, and behavior.

These drugs are classified based on their effects and their physiological mechanisms into categories such as stimulants, depressants, opiates, and hallucinogens.

Stimulants like caffeine, nicotine, amphetamines, and cocaine activate the central nervous system to increase alertness and energy. Excessive caffeine intake, for example, can raise heart rate and may lead to caffeine dependency.

Depressants such as alcohol, barbiturates, tranquilizers, and opiates slow brain and physical activity to promote relaxation and reduce anxiety. Heavy use of depressants can impair cognitive functions such as memory and decision-making and decrease vital signs like heart rate.

Opiates, for instance, morphine and heroin, are used for pain relief and can induce feelings of euphoria. Despite their effectiveness, they pose a high risk of addiction and can suppress breathing.

Hallucinogens, like Lysergic acid diethylamide, known as LSD, profoundly change perceptions and emotions, often causing visual hallucinations and significant mood variations.