Stimulants:These are substances that increase alertness, energy, and elevate mood. Examples include caffeine, nicotine, and amphetamines.
Depressants:Depressants are substances that slow down brain activity, resulting in relaxation, sedation, and reduced anxiety. Alcohol and benzodiazepines fall into this category.
Hallucinogens:Hallucinogens are drugs that cause alterations in perception, thought processes, and sensory experiences. Examples include LSD (acid), psilocybin mushrooms, and peyote cactus.