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: Their data suggest that both genders showed a "bimodal distribution of suicides and the sexes, but did not differ significantly from each other (x@=l2.29, d.f.=ll, P>0.30)". The authors hypothesized that the high summer peaks in suicide deaths are the result of an ultimately disappointed hope amongst the emotionally discomforted that winter might bring an end to the "social isolation and depression brought about by the cold weather". In contrast to these findings, some studies indicate that males have only one peak of suicide during the spring and early summer while women show two peaks of suicide throughout the year, during the spring and fall: " The seasonal distribution of suicides among the 117 males was similar and showed a significant seasonality: spring and summer peaks (33 and 29%, respectively) and fall–winter lows (18% and 20%, respectively, χ2=7.684, d.f.=3, P=0.053)". 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).