Intoxication with central nervous system (CNS) depressant drugs (alcohol, opiates, sedative-hypnotics, solvents) may cause death either directly through depression of brainstem centres responsible for maintaining essential bodily functions such as respiration, or indirectly through accidental injury or inhalation of vomit. The effects of such drugs are additive, and thus although an overdose of a benzodiazepine is rarely fatal in itself, it may well cause death if taken together with another CNS depressant drug. Intoxication with central nervous system stimulant drugs such as cocaine and amphetamine may cause death directly through cardio- and cerebro-vascular complications, or indirectly through accidental or self-inflicted injuries sustained while psychotic. The regular use of all substances is associated with an increased risk of suicide and deliberate self-harm. (See appendix 3, page 117 for characteristic intoxication syndromes).