This page covers the roles of neurotransmitters in the nervous system and the effects of various psychoactive drugs. Stimulants enhance dopamine levels, while sedatives depress brain activity. Opioids...This page covers the roles of neurotransmitters in the nervous system and the effects of various psychoactive drugs. Stimulants enhance dopamine levels, while sedatives depress brain activity. Opioids manage pain but are addictive. Drugs like naloxone, antipsychotics, tranquilizers, and antidepressants modify neurotransmitter activity, influencing mental health. Psychedelics alter perception, and THC in marijuana affects appetite.