Haloperidol: A phenyl-piperidinyl-butyrophenone that is used primarily to treat SCHIZOPHRENIA and other PSYCHOSES. It is also used in schizoaffective disorder, DELUSIONAL DISORDERS, ballism, and TOURETTE SYNDROME (a drug of choice) and occasionally as adjunctive therapy in INTELLECTUAL DISABILITY and the chorea of HUNTINGTON DISEASE. It is a potent antiemetic and is used in the treatment of intractable HICCUPS. (From AMA Drug Evaluations Annual, 1994, p279)Antipsychotic Agents: Agents that control agitated psychotic behavior, alleviate acute psychotic states, reduce psychotic symptoms, and exert a quieting effect. They are used in SCHIZOPHRENIA; senile dementia; transient psychosis following surgery; or MYOCARDIAL INFARCTION; etc. These drugs are often referred to as neuroleptics alluding to the tendency to produce neurological side effects, but not all antipsychotics are likely to produce such effects. Many of these drugs may also be effective against nausea, emesis, and pruritus.Clozapine: A tricylic dibenzodiazepine, classified as an atypical antipsychotic agent. It binds several types of central nervous system receptors, and displays a unique pharmacological profile. Clozapine is a serotonin antagonist, with strong binding to 5-HT 2A/2C receptor subtype. It also displays strong affinity to several dopaminergic receptors, but shows only weak antagonism at the dopamine D2 receptor, a receptor commonly thought to modulate neuroleptic activity. Agranulocytosis is a major adverse effect associated with administration of this agent.Catalepsy: A condition characterized by inactivity, decreased responsiveness to stimuli, and a tendency to maintain an immobile posture. The limbs tend to remain in whatever position they are placed (waxy flexibility). Catalepsy may be associated with PSYCHOTIC DISORDERS (e.g., SCHIZOPHRENIA, CATATONIC), nervous system drug toxicity, and other conditions.Dopamine Antagonists: Drugs that bind to but do not activate DOPAMINE RECEPTORS, thereby blocking the actions of dopamine or exogenous agonists. Many drugs used in the treatment of psychotic disorders (ANTIPSYCHOTIC AGENTS) are dopamine antagonists, although their therapeutic effects may be due to long-term adjustments of the brain rather than to the acute effects of blocking dopamine receptors. Dopamine antagonists have been used for several other clinical purposes including as ANTIEMETICS, in the treatment of Tourette syndrome, and for hiccup. Dopamine receptor blockade is associated with NEUROLEPTIC MALIGNANT SYNDROME.Risperidone: A selective blocker of DOPAMINE D2 RECEPTORS and SEROTONIN 5-HT2 RECEPTORS that acts as an atypical antipsychotic agent. It has been shown to improve both positive and negative symptoms in the treatment of SCHIZOPHRENIA.Receptors, Dopamine D2: A subfamily of G-PROTEIN-COUPLED RECEPTORS that bind the neurotransmitter DOPAMINE and modulate its effects. D2-class receptor genes contain INTRONS, and the receptors inhibit ADENYLYL CYCLASES.Apomorphine: A derivative of morphine that is a dopamine D2 agonist. It is a powerful emetic and has been used for that effect in acute poisoning. It has also been used in the diagnosis and treatment of parkinsonism, but its adverse effects limit its use.Benzodiazepines: A group of two-ring heterocyclic compounds consisting of a benzene ring fused to a diazepine ring.Receptors, Dopamine: Cell-surface proteins that bind dopamine with high affinity and trigger intracellular changes influencing the behavior of cells.Promethazine: A phenothiazine derivative with histamine H1-blocking, antimuscarinic, and sedative properties. It is used as an antiallergic, in pruritus, for motion sickness and sedation, and also in animals.Tranquilizing Agents: A traditional grouping of drugs said to have a soothing or calming effect on mood, thought, or behavior. Included here are the ANTI-ANXIETY AGENTS (minor tranquilizers), ANTIMANIC AGENTS, and the ANTIPSYCHOTIC AGENTS (major tranquilizers). These drugs act by different mechanisms and are used for different therapeutic purposes.Psychomotor Agitation: A feeling of restlessness associated with increased motor activity. This may occur as a manifestation of nervous system drug toxicity or other conditions.Sulpiride: A dopamine D2-receptor antagonist. It has been used therapeutically as an antidepressant, antipsychotic, and as a digestive aid. (From Merck Index, 11th ed)Dopamine: One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.Pimozide: A diphenylbutylpiperidine that is effective as an antipsychotic agent and as an alternative to HALOPERIDOL for the suppression of vocal and motor tics in patients with Tourette syndrome. Although the precise mechanism of action is unknown, blockade of postsynaptic dopamine receptors has been postulated. (From AMA Drug Evaluations Annual, 1994, p403)Fluphenazine: A phenothiazine used in the treatment of PSYCHOSES. Its properties and uses are generally similar to those of CHLORPROMAZINE.Receptors, sigma: A class of cell surface receptors recognized by its pharmacological profile. Sigma receptors were originally considered to be opioid receptors because they bind certain synthetic opioids. However they also interact with a variety of other psychoactive drugs, and their endogenous ligand is not known (although they can react to certain endogenous steroids). Sigma receptors are found in the immune, endocrine, and nervous systems, and in some peripheral tissues.Thioridazine: A phenothiazine antipsychotic used in the management of PHYCOSES, including SCHIZOPHRENIA.Schizophrenia: A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.Dopamine Agonists: Drugs that bind to and activate dopamine receptors.Chlorpromazine: The prototypical phenothiazine antipsychotic drug. Like the other drugs in this class chlorpromazine's antipsychotic actions are thought to be due to long-term adaptation by the brain to blocking DOPAMINE RECEPTORS. Chlorpromazine has several other actions and therapeutic uses, including as an antiemetic and in the treatment of intractable hiccup.Phencyclidine: A hallucinogen formerly used as a veterinary anesthetic, and briefly as a general anesthetic for humans. Phencyclidine is similar to KETAMINE in structure and in many of its effects. Like ketamine, it can produce a dissociative state. It exerts its pharmacological action through inhibition of NMDA receptors (RECEPTORS, N-METHYL-D-ASPARTATE). As a drug of abuse, it is known as PCP and Angel Dust.Trifluperidol: A butyrophenone with general properties similar to those of HALOPERIDOL. It is used in the treatment of PSYCHOSES including MANIA and SCHIZOPHRENIA. (From Martindale, The Extra Pharmacopoeia, 30th ed, p621)Emergency Services, Psychiatric: Organized services to provide immediate psychiatric care to patients with acute psychological disturbances.DibenzothiazepinesStereotyped Behavior: Relatively invariant mode of behavior elicited or determined by a particular situation; may be verbal, postural, or expressive.Receptors, Dopamine D3: A subtype of dopamine D2 receptors that are highly expressed in the LIMBIC SYSTEM of the brain.Pirenzepine: An antimuscarinic agent that inhibits gastric secretion at lower doses than are required to affect gastrointestinal motility, salivary, central nervous system, cardiovascular, ocular, and urinary function. It promotes the healing of duodenal ulcers and due to its cytoprotective action is beneficial in the prevention of duodenal ulcer recurrence. It also potentiates the effect of other antiulcer agents such as CIMETIDINE and RANITIDINE. It is generally well tolerated by patients.Neurotensin: A biologically active tridecapeptide isolated from the hypothalamus. It has been shown to induce hypotension in the rat, to stimulate contraction of guinea pig ileum and rat uterus, and to cause relaxation of rat duodenum. There is also evidence that it acts as both a peripheral and a central nervous system neurotransmitter.Phenazocine: An opioid analgesic with actions and uses similar to MORPHINE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1095)Spiperone: A spiro butyrophenone analog similar to HALOPERIDOL and other related compounds. It has been recommended in the treatment of SCHIZOPHRENIA.Pentazocine: The first mixed agonist-antagonist analgesic to be marketed. It is an agonist at the kappa and sigma opioid receptors and has a weak antagonist action at the mu receptor. (From AMA Drug Evaluations Annual, 1991, p97)Clopenthixol: A thioxanthene with therapeutic actions similar to the phenothiazine antipsychotics. It is an antagonist at D1 and D2 dopamine receptors.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Ritanserin: A selective and potent serotonin-2 antagonist that is effective in the treatment of a variety of syndromes related to anxiety and depression. The drug also improves the subjective quality of sleep and decreases portal pressure.Corpus Striatum: Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.Remoxipride: An antipsychotic agent that is specific for dopamine D2 receptors. It has been shown to be effective in the treatment of schizophrenia.Butyrophenones: Compounds containing phenyl-1-butanone.Butaclamol: A benzocycloheptapyridoisoquinolinol that has been used as an antipsychotic, especially in schizophrenia.Homovanillic AcidRats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Startle Reaction: A complex involuntary response to an unexpected strong stimulus usually auditory in nature.Anti-Dyskinesia Agents: Drugs used in the treatment of movement disorders. Most of these act centrally on dopaminergic or cholinergic systems. Among the most important clinically are those used for the treatment of Parkinson disease (ANTIPARKINSON AGENTS) and those for the tardive dyskinesias.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Quinpirole: A dopamine D2/D3 receptor agonist.Basal Ganglia Diseases: Diseases of the BASAL GANGLIA including the PUTAMEN; GLOBUS PALLIDUS; claustrum; AMYGDALA; and CAUDATE NUCLEUS. DYSKINESIAS (most notably involuntary movements and alterations of the rate of movement) represent the primary clinical manifestations of these disorders. Common etiologies include CEREBROVASCULAR DISORDERS; NEURODEGENERATIVE DISEASES; and CRANIOCEREBRAL TRAUMA.Receptors, Phencyclidine: Specific sites or molecular structures on cell membranes or in cells with which phencyclidine reacts or to which it binds to elicit the specific response of the cell to phencyclidine. Studies have demonstrated the presence of multiple receptor sites for PCP. These are the PCP/sigma site, which binds both PCP and psychotomimetic opiates but not certain antipsychotics, and the PCP site, which selectively binds PCP analogs.Clorazepate Dipotassium: A water-soluble benzodiazepine derivative effective in the treatment of anxiety. It has also muscle relaxant and anticonvulsant actions.PyrrolidinesDibenzothiepinsSerotonin Receptor Agonists: Endogenous compounds and drugs that bind to and activate SEROTONIN RECEPTORS. Many serotonin receptor agonists are used as ANTIDEPRESSANTS; ANXIOLYTICS; and in the treatment of MIGRAINE DISORDERS.Delirium: A disorder characterized by CONFUSION; inattentiveness; disorientation; ILLUSIONS; HALLUCINATIONS; agitation; and in some instances autonomic nervous system overactivity. It may result from toxic/metabolic conditions or structural brain lesions. (From Adams et al., Principles of Neurology, 6th ed, pp411-2)Serotonin Antagonists: Drugs that bind to but do not activate serotonin receptors, thereby blocking the actions of serotonin or SEROTONIN RECEPTOR AGONISTS.Chlordiazepoxide: An anxiolytic benzodiazepine derivative with anticonvulsant, sedative, and amnesic properties. It has also been used in the symptomatic treatment of alcohol withdrawal.Amphetamine: A powerful central nervous system stimulant and sympathomimetic. Amphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulation of release of monamines, and inhibiting monoamine oxidase. Amphetamine is also a drug of abuse and a psychotomimetic. The l- and the d,l-forms are included here. The l-form has less central nervous system activity but stronger cardiovascular effects. The d-form is DEXTROAMPHETAMINE.Dextroamphetamine: The d-form of AMPHETAMINE. It is a central nervous system stimulant and a sympathomimetic. It has also been used in the treatment of narcolepsy and of attention deficit disorders and hyperactivity in children. Dextroamphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulating release of monamines, and inhibiting monoamine oxidase. It is also a drug of abuse and a psychotomimetic.3,4-Dihydroxyphenylacetic Acid: A deaminated metabolite of LEVODOPA.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Bromocriptine: A semisynthetic ergotamine alkaloid that is a dopamine D2 agonist. It suppresses prolactin secretion.