Alcoholism: theoretical consideration of season of birth and geographic latitude.

Several neurological and immune phenomena associated with cerebral laterality also show an atypical season of birth pattern. Alcoholism is also associated with cerebral laterality. In this pilot study (n = 292), 66% of right-handed alcoholic men were born during the summer and fall (expected 52%, p less than 0.001). This finding suggests that at high latitude more right-handed men would become alcoholic because seasonal effects usually intensify with increasing latitude. In addition, in our sample of alcoholic men, left-handedness was associated with having an alcoholic father or with being first-born. Together, these findings suggest that the prevalence of alcoholism should increase with increasing latitude, and that the frequency in alcoholic men of being left-handed, first-born or having an alcoholic father should decrease with increasing latitude. The available literature tends to substantiate these correlations, but more systematic studies of season of birth and correlations with latitude in alcoholism are required.