The popular name for drugs which induce a mental state free from agitation and anxiety, and renders the patient calm. Tranquillisers are classified as major and minor. The former are used to treat psychotic illness such as SCHIZOPHRENIA; the latter are sedatives used to treat anxiety and emotional upsets (see NEUROSIS) and are called antianxiety drugs or ANXIOLYTICS. Major tranquillisers are the antipsychotic drugs given to patients whose psychotic disorders disrupt their normal lives (see PSYCHOSIS). They do not cure the patient, but help to control symptoms so that individuals affected can live in the community. The drug chosen depends upon the type of illness and needs of a particular patient as well as the likely adverse effects. Antipsychotic drugs modify the transmission of nerve-signals by making brain cells less sensitive to the excitatory neurotransmitter chemical called DOPAMINE. Among the antipsychotic tranquillisers are CHLORPROMAZINE, HALOPERIDOL, CLOZAPINE and flupenthixol.

Clinically it arises when the balance between certain chemicals in the brain is disturbed: this increases activity in the sympathetic system, thus provoking physical symptoms such as breathlessness, tachycardia, headaches and indigestion. Anxiolytics help to alleviate these symptoms but do not necessarily cure the underlying cause. Two main classes of drug relieve anxiety: BENZODIAZEPINES and beta blockers (see BETA-ADRENOCEPTOR-BLOCKING DRUGS (BETA BLOCKERS)). The latter, which include atenolol and propanolol, reduce the physical symptoms such as tachycardia and are sometimes advised to help deal with circumstances known to cause anxiety attacks, for example, examinations. They block the action of NORADRENALINE, a key chemical of the sympathetic nervous system. Benzodiazepines depress activity in that part of the brain controlling emotion by stimulating the action of a chemical called gamma-aminobutyric acid (GABA). Anxiety related to STRESS may not require medication. (See also MENTAL ILLNESS.)