Trait markers for alcoholism: Clinical utility

Because alcoholism is a multi-factorial psychiatric disorder, with both psy chosocial and biochemical/genetic factors leading to its manifestation in a ny one individual, the presence of biochemical/genetic factors alone may no t lead to the manifestation of the disorder. There are numerous difficultie s associated with identification of a trait abnormality in a disorder that requires suitable socio-cultural permissiveness with distinct behavioural c haracteristics to manifest a disorder that may not require that predisposin g trait abnormality in order to develop. Numerous studies have been perform ed in the past to potentially identify a biochemical or genetic trait abnor mality in alcoholism, and not all of them have addressed significant method ological flaws in this type of research. This review addresses some of the difficulties inherent in this research, and aims for a comprehensive review of the highlights of the search for a clinically useful trait abnormality. Some series of investigations hold promise that a trait marker for a parti cular subset of alcoholics may be developed, e.g. severe alcoholism and the dopamine D2 receptor gene; the level of reaction to alcoholism in family h istory-positive alcoholics; beta-endorphin abnormalities in specific family groups of alcoholics; reduced P3 wave event-related potentials as markers and predictors of development of substance abuse in predisposed youths; red uced growth hormone response to apomorphine as a predictor of relapse to al coholism in early abstinence; abnormal adenylyl cyclase activity in certain defined subgroups of alcoholics; and abnormal platelet monoamine oxidase l evels in subjects with a behavioural predisposition to addictive disorders. The review concludes that while there has not yet been an identification o f a comprehensive trait marker for alcoholism, there is hope for identifica tion subgroups of alcoholics with consistent biological markers within that subgroup that may well prove fruitful over time. It will then be up to a f uture generation of clinicians to take that information and develop prevent ion programmes that can incorporate this information to help the predispose d individual avoid alcohol problems.