Space and earth weather mirrored in patterns of suicide incidence

Abstract

Exploring any non-photic as well as photic components in the spectrum of the incidence pattern of suicides, we find gender differences in Minnesota, USA, and Australia, notably in the para-annual range of the spectrum. A trans-tridecadal BEL cycle (also more liberally referred to as para-tridecadal) with a period of about 35 years is found in data pooled from both genders and separately for both men and women in Finland (1969-2007). When fitted separately as a single component, the estimated period and its 95% confidence interval (CI) (in years) is 35.5 [26.7, 44.3] overall, 36.4 [25.3, 47.5] for males, and 38.9 [28.5, 49.3] for females, with respective amplitudes (N/100,000) of 170 [119, 222], 145 [98, 192], and 29 [18, 40]. Differences between a Schwabe cycle and an about 7-year component (possibly a harmonic of the Hale cycle) characterizing suicide patterns of Finnish men and women, respectively, remain to be examined in longer series. In Bulgaria (1929-1945), a far-transyear with a period of about 1.3 years is noteworthy as is a quinmensal component with an about 5-month period. In France (1979-2008), in males and females, suicides are characterized by about 10.0-year and 10.1-year cycles, respectively. In Japan (1987-1999), an about 12.7-year component is detected, albeit with a broad uncertainty. A better understanding of the origin of these patterns, notably in terms of the relative contribution of non-photic and photic (daily and yearly) cycles, may lead to better prediction of incidence dynamics and to novel interventions for the prevention of major depression and suicide.