Introduction

Psychopharmacology offers a range of psychotropic medications to the medical practitioner. The decision to administer such medicines should be made in the context of evidence-based, realistic risk–benefits assessment and sound clinical judgement. With many psychotropics there is a potential for dependence. This can be manifest in two ways; tolerance, where an increased dose is required to produce the same effect, and withdrawal where negative psychological and/or physical consequences are associated with drug discontinuation. Such effects have been characterized in detail from studies of opiate addiction (see ‘Drug dependency: opiates and stimulants’). The following sections summarizes specific health aspects of selected ‘recreational’ and prescription psychotropic agents.

Tobacco

Cigarette smoking leads to around 130 000 deaths annually in the UK. Part of the addictive potential of cigarettes lies in the delivery system; inhaled tobacco smoke generates a nicotine ‘hit’ within 10 seconds of inhalation, although nicotine dependence is also evident from other routes such as chewing tobacco. The behavioural effects are due to nicotine binding nicotinic acetylcholine receptors and in regular smokers cholinergic neuroadaptations probably underlie nicotine cravings during abstinence. These are transiently relieved by nicotine administration: indeed there is now strong evidence that while the regular smoker relieves negative effects of nicotine withdrawal they do not gain anything positive (Parrott et al., 2004). Historically it was believed that smoking relieved stress: however there is now strong evidence that nicotine dependence itself causes stress (Parrott, 1999).