Behavioural correlates of alcohol intoxication.

Alcohol is used in most cultures despite knowledge of the physical, psychological and social problems associated with its abuse. Behavioural impairment is a function of several factors, including blood alcohol concentration (BAC) and the rate of alcohol metabolism by alcohol dehydrogenase and the microsomal ethanol-oxidizing system. Their availability and activity depend upon alcohol use history, ethnicity, other drug use and gender. Adverse social consequences related to alcohol intoxication include impaired driving, acts of aggression and violence towards self and others, and various types of accidents. About 40% of all fatal traffic accidents in Canada and the US in 1986-1987 were alcohol-related. Similar statistics have been reported in the UK and Europe (e.g. Sweden). The risk of a fatal car accident increases exponentially with a driver's BAC, prompting recommendations to lower the legal BAC limit for driving and piloting aircraft. Risks of falls, drownings, and fires and burns may also be increased by alcohol intoxication. At least 22% of work-related accidents may have involved alcohol use. These data are probably conservative estimates as under-reporting of alcohol use is likely. Alcohol facilitates aggressive behaviours, but it is difficult to separate the pharmacological effect from psychosocial effects or some other common factor (e.g. low CSF levels of the serotonin metabolite 5-H1AA have been reported in alcoholics, suicide attempters, violent offenders). In addition, alcohol interacts with other drugs to increase or decrease their behavioural and therapeutic effects. An acutely high BAC inhibits the metabolism of other CNS depressants (e.g. benzodiazepines), but long-term alcohol use increases the metabolism of most drugs. A potential amethystic agent, to block or reverse alcohol's effects, has been identified in preclinical studies (Ro15-4513, an imidazobenzodiazepine). Some clinical studies indicated that naloxone, lithium, ibuprofen, zimeldine and catecholamine agonists may reduce ethanol-induced behavioural or cognitive effects but the results have not been consistently replicated. More research is needed to determine the potential clinical use of amethystic agents and other pharmacotherapies in the prevention and treatment of problem behaviours associated with alcohol abuse and intoxication.