Title: Seasonal effects on suicide rates - Wikipedia
Headings: Seasonal effects on suicide rates
Seasonal effects on suicide rates
Contents
General effects
Popular belief
Related factors
Gender
Biochemistry
Environment
Psychology
See also
References

Content: Biochemistry
Biological explanations of seasonal effects on suicide rates tend to focus on seasonal variation in hormone changes and neurotransmitter levels. Chronobiological research, conducted by a team of clinical scientists in Belgium, has revealed that many "biochemical, metabolic and immune functions, which may be related to suicide, suicidal behavior or ideation or major depression, are organized along a multifrequency seasonal time-structure". Evidence was found by calculating "serum total cholesterol concentrations to show a clear seasonality with lower levels in midyear than in winter" Similarly, medical researchers in Pennsylvania indicate that neuropeptides in normal controls have lower serum cholesterol levels and may be related to a higher occurrence of suicide. These findings clearly state that there is a relationship between summer suicide rates and biochemical (e.g., plasma L-TRP and melatonin levels, [3H]paroxetine binding to blood platelets), metabolic (serum total cholesterol, calcium and magnesium concentrations), and immune (number of peripheral blood lymphocytes and serum sIL-2R) variables. Another study focused on the association between depression, suicide, and the amount of polyunsaturated fatty acids (PUFA). They state that "depression is accompanied by a depletion of n-3 poly-unsaturated fatty acids". Their methodology involved taking periodic blood samples—every month for one year—of healthy volunteers, allowing them to analyze the "PUFA composition in serum phospholipids and [relating] those data to the annual variation in the mean weekly number of suicides". They used an analysis of variance (ANOVA) to document their results, finding that PUFA like arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid all occurred at significantly lower rates in winter than in summer months. The association between depression, suicide, and PUFA rates is indicative of there being a biological factor in seasonal effects on suicide rates. Environment
Environmental variables, such as the amount of sunlight, occurrence of natural disasters, and the inability to protect and shelter oneself, can result in suicidal behaviors.