Low cholesterol increases depression

Men with low cholesterol have a higher death rate from injury. Although cholesterol-lowering tends to reduce CHD mortality in certain age groups, there is no evidence that low cholesterol reduces total mortality. In populations with naturally low blood cholesterol there is also a significant death rate from ‘non-medical’ causes. Why is there this association?

A pilot study into blood cholesterol and depression in schizophrenics found a highly significant interaction between low levels of cholesterol and depression. Extreme lowering of cholesterol with drugs altered the functional state of the ‘feel good’ hormone, seratonin. The authors suggest that ‘the degree of the low cholesterol combined with its duration might be a risk factor for the development of an abnormal mental state.’[1] Dr A Ryman, writing in the British Medical Journal says: ‘Our current understanding of the relation between cholesterol metabolism and psychiatric illness is poor . . . The possibility that a low or falling cholesterol concentration is a marker of risk merits further study.’[2]

A large study at the Cholesterol Center, Jewish Hospital, Cincinnati, Ohio aimed to assess the relation between cholesterol levels and affective disorders such as depression, bipolar disorder and schizophrenia disorder.[3] Cholesterol concentrations below 4.16 mmol/L (160 mg/dL) were much more common in patients with these disorders. When paired with healthy people of a similar sex and age, patients had much lower total cholesterol, LDL and HDL.

Dr M Law added confirmation two years later. He writes: ‘treating depression has been shown to increase serum cholesterol concentration. . . . Low serotonin concentrations (which accompany and may cause depression) are, not surprisingly, also associated with low cholesterol, people who attempt suicide have low serum cholesterol concentrations, . . . men with declining serum cholesterol concentrations are particularly likely to commit suicide.’[4]

References
1. Dursun SM, Burke JG, Reveley MA. Low serum cholesterol and depression. BMJ 1994; 309: 273-4
2. Ryman A. Cholesterol, violent death, and mental disorder. BMJ 1994; 309: 421-2
3. Glueck CJ, Tieger M, Kunkel R, et al. Hypocholesterolemia and affective disorders. Am J Med Sci 1994; 308: 218-25.
4. Law M. Having too much evidence (depression, suicide and low serum cholesterol). BMJ 1996; 313: 651-2.P