AbstractsPsychology

Suicide continues to claim hundreds of thousands of lives worldwide each year, in spite of the significant progress of research efforts aimed at understanding the complexity of this tragic behaviour. Data accumulated over the last decades suggest a certain biological predisposition to suicidal behaviour. Among the possible biological risk factors, cholesterol has frequently been cited. Several lines of evidence support the relationship between altered lipid metabolism, particularly low levels of serum cholesterol, and suicidal behaviour, yet the possible mechanisms governing the relationship remain to be elucidated. Three separate strategies were employed in order to explore the link between lipid metabolism and suicidal behaviour, each one from a novel perspective on this issue. The first approach aimed to substantiate the existing evidence of an association between low serum cholesterol and suicidality by examining psychiatric data, suicidality and related behavioural characteristics in a sample of Smith-Lemli-Opitz syndrome heterozygotes – a clinically normal population with altered cholesterol metabolism due to an inherited partial deficiency in the 7-dehydrocholesterol reductase enzyme – compared with controls. The second approach consisted in measuring the lipid profile in brain tissue from suicide completers, in order to address whether there are alterations in cholesterol and/or fatty acids in the brain. The final approach involved the use of exploratory gene expression studies to identify novel candidate genes and proteins that may be involved in mediating the link between lipid metabolism and suicidality. The results of these studies will be presented and discussed.