[2] They are central nervous system (CNS) depressants and interact with brain activity causing its deceleration.

Advances in pharmacology have permitted more specific targeting of receptors, and greater selectivity of agents, which necessitates greater precision when describing these agents and their effects: The term "chemical cosh" (cosh being a term for a blunt weapon such as a club) is sometimes used colloquially for a strong sedative, particularly for: [citation needed]Doctors and veterinarians often administer sedatives to patients in order to dull the patient's anxiety related to painful or anxiety-provoking procedures.

[citation needed] Some sedatives can cause psychological and physical dependence when taken regularly over a period of time, even at therapeutic doses.

Benzodiazepines comparatively have a wider margin of safety and rarely result in overdose unless mixed with other CNS depressants.

[10] Accidental deaths sometimes occur when a drowsy, confused user repeats doses, or when sedatives are taken with alcohol.

Malcolm Lader at the Institute of Psychiatry in London estimates the incidence of these adverse reactions at about 5%, even in short-term use of the drugs.

The paradoxical reactions may consist of depression, with or without suicidal tendencies, phobias, aggressiveness, violent behavior and symptoms sometimes misdiagnosed as psychosis.

Intensive care unit patients who receive higher doses over longer periods, typically via IV drip, are more likely to experience such side effects.

Sedatives — most commonly alcohol,[26] but also GHB, flunitrazepam (Rohypnol), and to a lesser extent, temazepam (Restoril) and midazolam (Versed)[27] — have been reported for their use as date rape drugs (also called a Mickey Finn) and being administered to unsuspecting patrons in bars or guests at parties to reduce the intended victims' defenses.