The relationship between low cholesterol levels and increased risk of suicide was revealed in 1980s. The 1990 metaanalyis ( Muldoon et al) showed that with 10% reduction in cholesterol, there were 28 fewer deaths due to ischaemic heart disease, but 29 more deaths due to suicide, violence and accidents. Low cholesterol has since been shown to predict future suicide during follow ups of individuals with depression. Cholesterol lowering interventions, in later studies , generally show a reduction in mortality from all causes.
A recent study (Baek et al 2014) found that among those with depression, recent suicide attempters had significantly lower triglyceride and higher HDL cholesterol levels. The literature generally supports the idea that lower lipid levels ( cholesterol, TG) are associated with increasing suicidal ideas, acts and suicide.
It is thought that low cholesterol lead to decreased activity of serotonergic system. Another interesting observation is the increase in 24 hydroxyesterol ( oxidation product of cholesterol) in prefrontal cortex of suicide victims suggesting higher turn over of cholesterol in brain and this leading to decrease in levels elsewhere raising the possibility that lowering of cholesterol is secondary to suicidal ideas/depressive cognition.
It has to be mentioned that many studies in Asian population did not find support for the association between low cholesterol and suicide.
Ainiyet et al from Poznan University of Medical Sciences ( Poland) studied lipid levels in unipolar and bipolar depression.They interviewed 223 patients to assess suicidal ideas, acts in the 3 months prior to admission. Lipid levels were measured to study the relationship.
Half of the depressed men and 39% of women reported suicidal ideas. Concentrations of total cholesterol, LDL cholesterol, triglycerides and total lipids were significantly lower in depressed patients with suicidal thoughts. Gender and diagnosis ( i.e. whether unipolar or bipolar) did not change this relationship.
Limitations: cross-sectional study.
Conclusion: Low cholesterol is linked to suicidal ideas in unipolar and bipolar depression. This study support the earlier findings.
Summary of the article:
Ainiyet B, Rybakowski JK. Acta Neuropsychiatr. 2014 Oct;26(5):315-20.