The popular name for drugs which induces 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 and are called antianxiety drugs or anxiolytics. Major tranquillisers are the antipsychotic drugs given to patients whose psychotic disorders disrupt their normal lives. 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.