the neuroleptics antagonize dopamine receptors broadly, also reducing the normal dopamine-mediated inhibition of cholinergic cells in the striatum. Second-generation (atypical) antipsychotics: The concept of "atypicality" is from the finding that second generation antipsychotics (SGAs) have a greater serotonin/dopamine ratio than earlier drugs, and might be associated with improved efficacy (particularly for the negative symptoms of psychosis) and reduced extrapyramidal side effects. Some of the efficacy of atypical antipsychotics may be due to 5-HT2 antagonism or the blockade of other dopamine receptors. Agents that purely block 5-HT2 or dopamine receptors other than D2 have often failed as effective antipsychotics. Benzodiazepines Benzodiazepines are often used to reduce anxiety symptoms, muscle tension, seizure disorders, insomnia, symptoms of alcohol withdrawal, and panic attack symptoms. Their action is primarily on specific benzodiazepine sites on the GABAA receptor. This receptor complex is thought to mediate the anxiolytic, sedative, and anticonvulsant actions of the benzodiazepines. Use of benzodiazepines carries the risk of tolerance (necessitating increased dosage), dependence, and abuse. Taking these drugs for a long period of time can lead to severe withdrawal symptoms upon abrupt discontinuation. Hallucinogens Classical Serotonergic Psychedelics Psychedelics cause perceptual and cognitive distortions without delirium. The state of intoxication is often called a "trip". Onset is the first stage after an individual ingests (LSD, psilocybin, ayahuasca, and mescaline) or smokes (dimethyltryptamine) the substance. This stage may consist of visual effects, with an intensification of colors and the appearance of geometric patterns that can be seen with one's eyes closed. This is followed by a plateau phase, where the subjective sense of time begins to slow and the visual effects increase in intensity. The user may experience synesthesia, a crossing-over of sensations (for example, one may "see" sounds and "hear" colors). These outward sensory effects have been referred to as the "mystical experience", and current research suggests that this state could be beneficial to the treatment of some mental illnesses, such as depression and possibly addiction. In instances where some patients have seen a lack of improvement from the use of antidepressants, serotonergic hallucinogens have been observed to be rather effective in treatment. In addition to the sensory-perceptual effects, hallucinogenic substances may induce feelings of depersonalization, emotional shifts to a euphoric or anxious/fearful state, and a disruption of logical thought. Hallucinogens are classified chemically as either indolamines (specifically tryptamines), sharing a common structure with serotonin, or as phenethylamines, which share a common structure with