BIOCHEMICAL, METABOLIC AND IMMUNE CORRELATES OF SEASONAL-VARIATION INVIOLENT SUICIDE - A CHRONOEPIDEMIOLOGIC STUDY

The purpose of this chronoepidemiologic study was to investigate the t ime-relationships between the yearly variations in occurrence of viole nt suicide in Belgium and the yearly variations in various biochemical , metabolic and immune variables in the Belgian population, The weekly mean number of deaths due to violent suicide for all of Belgium for t he period 1979-1987 was computed. Twenty-six normal volunteers had mon thly blood samplings during one calendar year for assays of plasma L-t ryptophan (L-TRP), competing amino acids (CAA), and melatonin levels, maximal [3H]paroxetine binding to platelets, serum total cholesterol, calcium, magnesium, and soluble interleukin-2 receptor concentrations, and number of CD4+ T, CD8+ T and CD20+ B lymphocytes. The annual rhyt hm in violent suicide rate is highly significantly synchronized with t he annual rhythms in L-TRP, [3H]paroxetine binding, cholesterol, calci um, magnesium, CD20+ B cells, and CD4+/CD8+ ratio; the mean peak (viol ent suicide, [3H]paroxetine binding) or nadir (all other variables) oc curs around 3 May. There were significant inverse time-relationships b etween the time series of violent suicide rate and L-TRP, L-TRP/CAA ra tio, total cholesterol, calcium and magnesium, CD4+/CD8+ T cell ratio and number of CD20+ B cells, Maximal [3H]paroxetine binding to platele ts was significantly and positively related to the time series of viol ent suicide. An important part (56.4%) of the variance in mean weekly number of violent suicide rate was explained by the time series of L-T RP, cholesterol and melatonin.