Evidence that latitude is directly related to variation in suicide rates.
OBJECTIVE
To use available suicide-rate data from 20 countries to see patterns and relations more clearly.


METHODS
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.
Davis
George E
GE
Augusta Mental Health Institute, Augusta, Maine, USA. george.davis@state.me.us
Lowell
Walter E
WE
D001315:Australia / Q000453:epidemiology; D002170:Canada / Q000453:epidemiology; D002980:Climate; D005060:Europe / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008027:Light; D009520:New Zealand / Q000453:epidemiology; D013405:Suicide / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology