Although primary prevention studies have shown that reducing serum cholesterol concentration leads to a clear reduction in cardiac morbidity and mortality, total mortality is unaffected. The increase in deaths from accidents, violence, and suicide in the treated groups has not yet been adequately explained,1 though an association between low cholesterol concentration and psychiatric illness has been suggested as a possible cause.2 The finding has also been elaborated in neurobiological terms, implicating a relation between membrane cholesterol, serotonin, and impulsivity.3

How seriously should this association be taken? Is the apparent relation of suicidal, accidental, and violent death with low serum cholesterol concentrations a true finding or simply due to chance? The association was initially regarded as an anomalous occurrence, but it has been too consistent to be dismissed.4 It has appeared in studies …