Letter to the Editor

The relationship between cholesterol and suicide has been paid consistent attention for the last decade, and cholesterol seems very important in the primary prevention of suicide. In regard to this point, we read with much interest the review by Brunner et al. [1], but their conclusion seems to deviate from the findings of the current research. We would like to make some comments as follows.

First, as introduced by Brunner et al. [1], Muldoon et al.’s [3] earlier meta-analysis of primary prevention trials revealed that lowering cholesterol levels might increase non-illness mortality from suicide, trauma, accidents, and violence. Recently, however, the same authors [4] re-evaluated the potential effects of cholesterol interventions on non-illness mortality with another meta-analysis of further randomized clinical trials and concluded that non-illness mortality is not increased significantly by cholesterol-lowering treatment. Therefore, lowering cholesterol does not seem to increase suicide.

Secondly, Brunner et al. [1] concluded that naturally occurring low cholesterol levels are not associated with increased risk of depression or suicide. However, we found that depressive states varied significantly across cholesterol levels in a large number of subjects after adjustment for age, body mass index, total protein, weight loss, and concomitant medical diagnoses and that the lowest cholesterol group was more likely to be in a dpressive state [8]. Kim et al. [2] also revealed that patients who had attempted suicide had significantly lower cholesterol levels than did psychiatric and normal controls and that cholesterol levels and the severity of suicide attempt were inversely correlated. Moreover, Schatz et al. [5] reported that low cholesterol levels were associated with all-cause mortality in elderly men and that long-term persistence of low cholesterol levels increased the risk of death. These findings suggest that naturally occurring low cholesterol levels are associated with increased risk of suicide.

Thirdly, Brunner et al. [1] indicated the possibility that omega-3 fatty acid rather than cholesterol may affect suicide, because in vitro and animal experiments regarding cholesterol and serotonergic function are of doubtful clinical relevance. However, we repeatedly showed that serum cholesterol levels were positively associated with serotonergic receptor function in healthy volunteers using a neuroendocrine chanllenge test [6] [7]. Our findings suggest the possibility that low cholesterol levels are associated with low serotonergic neurotransmission, which probably leads to depression and/or suicide [7].

In conclusion, these current findings suggest that low rather than lowering cholesterol levels may directly induce suicide via serotonergic hypoactivity. Further studies are needed to confirm this relationship, although the effect of omega-3 fatty acids also deserves further investigation.

References

• 1 Brunner J, Parhofer K G, Schwandt P, Bronisch T. Cholesterol, essential fatty acids, and suicide.  Pharmacopsychiatry. 2002;  35 1-5
• 2 Kim Y -K, Lee H -J, Kim J -Y, Yoon D -K, Choi S -H, Lee M -S. Low serum cholesterol is correlated to suicidality in a Korean sample.  Acta Psychiatr Scand. 2002;  105 141-148
• 3 Muldoon M F, Manuck S B, Matthews K A. Lowering cholesterol concentrations and mortality: a quantitative review of primary prevention trails.  BMJ. 1990;  301 309-314
• 4 Muldoon M F, Manuck SB; Mendelsohn AB; Kaplan J R, Belle S H. Cholesterol reduction and non-illness mortality: meta-analysis of randomized clinical trials.  BMJ. 2001;  322 11-16
• 5 Schatz I J, Masaki K, Yano K, Chen R, Rodriguez B L, Curb J D. Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study.  Lancet. 2001;  358 351-355
• 6 Terao T, Yoshimura R, Ohmori O, Takano T, Takahashi N, Iwata N. et al . Effect of serum cholesterol levels on meta-chlorophenylpiperazine-evoked neuroendocrine responses in healthy subjects.  Biol Psychiatry. 1997;  41 974-978
• 7 Terao T, Nakamura J, Yoshimura R, Ohmori O, Takahashi N, Kojima H. et al . Relationship between serum cholesterol levels and meta-chlorophenylpiperazine-induced cortisol responses in healthy men and women.  Psychiatry Res. 2000;  96 167-173
• 8 Terao T, Iwata N, Kanazawa K, Takano T, Takahashi N, Hayashi T. et al . Low serum cholesterol levels and depressive state in human dock visitors.  Acta Psychiatr Scand. 2000;  101 231-234