To use available suicide-rate data from 20 countries to see patterns and relations more clearly.
Method:
We obtained raw suicide rates from the Organization for Economic Cooperation and Development (OECD) database from 1960 through 1997 and calculated averages and standard deviations.
Results:
There is a positive linear relation between the variation in suicide rate and geographic latitude.
Conclusions:
The variation in light-dark cycles is superimposed upon human mood.
TorreyEFMillerJRawlingsRYolkenRH. Seasonality of births in schizophrenia and bipolar disorder: A review of the literature. Schizophr Res1997;28:1–38.
2.
DaviesGAhmadFChantDWelhamJMcGrathJ.Seasonality of first admissions for schizophrenia in the southern hemisphere. Schizophr Res2000;41:457–62.
3.
ClarkeMMoranPKeoghFMorrisMKinsellaALarkinC, and others. Seasonal influences on admissions for affective disorder and schizophrenia in Ireland: A comparison of first and re-admissions. Eur Psychiatry1999;14:251–5.
4.
MortenGLinakerOM. Seasonal variation of violence in Norway. Am J Psychiatry2000;157:1674–8.
5.
OECD Health Data1999, 2, rue Andre Pascal, F-75775 Paris Cedex 16, France.
6.
MagnussonAAxelssonJ.The prevalence of seasonal affective disorder is low among descendants of Icelandic emigrants in Canada. Arch Gen Psychiatry1993;50:947–51.
7.
McMichaelAHallA.Does immunosuppressive ultraviolet radiation explain the latitude gradient for multiple sclerosis?Epidemiology1997;8:642–5.
8.
JablonskiN.A possible link between neural tube defects and ultraviolet light exposure. Med Hypotheses1999;52:581–2.
