Number of Suicides

One serious health problem faced by America is the number of people that kill themselves each year. An estimated 30,000 Americans, 20,000 of which are men, kill themselves each year. In 2004 alone, the U. S. government has spent almost $21 billion on medicine for depression, bipolar disorder, and schizophrenia. Despite these efforts, the rate of suicide remains unchanged at 11 per year per 100, 000 people (Dawdy, 2004). America’s known suicide capital is Seattle with a suicide rate of 13 per 100, 000. This is almost 20% higher than the national average. The suicide rate in Seattle is also three times higher than their murder rate (Dawdy, n. d. ).

For this reason, it is important to point the possible causes of the high incidence of suicide in the area. One reason being considered as the cause of high suicide numbers is the lack of sunlight. Seattle average only 58 clear days a year, occurring mostly between June to September. During the rest of the year, most days of the week are cloudy or partly cloudy. How is suicide connected to the lack of sunlight? In medicine, there is a condition known as the Seasonal Affective Disorder (SAD). SAD is a kind of depression that is triggered by the change in seasons.

Depression is one of the main causes of committing suicide. The more common time of SAD is the winter-onset SAD, a condition present in areas with longer winter season. It is estimated that almost half a million Americans may have winter-onset SAD. (“Seasonal Affective Disorder,” 2000) The cause of SAD remains a puzzle but researchers think the condition is related to the levels of melatonin in the human body. Melatonin is the hormone responsible of the feeling of drowsiness. It is produced by the pineal gland and its production is directly related to the hibernation cycles of mammals.

In high levels of light, the production of melatonin is inhibited, thus the body is in a wake mood. During the night, and on winter days where there is prolonged lack of light, there is no enough light to trigger the inhibition process. The human body becomes more sleepy and sluggish (Emundson, 2000). The occurrence of SAD has been also related to the production of the neurotransmitter serotonin. Serotonin influences the mood of a person and it is though that low levels of serotonin causes SAD. The relationship of lack of sunlight and suicide attempts has yet to be established. Dogonay et al.

(2003) tried to study the correlation of climatic factors and suicidal behavior. They studied 1,119 suicide attempts and found out there was a clear seasonal variation. Suicide attempts were frequent from 6 to 9 PM for males, and 3 to 6 PM for females. However, their study found a positive correlation between the intensity and duration of sunlight to the number of suicide attempts, and a negative correlation between cloudiness and the number of suicide attempts. The same observation was made by Bjorksten et al. (2009) when they studied the seasonality of suicides in West Greenland.

Greenland has one of the most extreme climates on earth. Results of the study showed that suicide incidences were higher in June (summer) rather than winter. It seems that the lack of sunlight is more related to the type of suicide being committed (violent vs. non-violent). Wijngaarden and Savitz (2000) worked the relationship of sunlight exposure and suicide among utility workers. They found no dose-response gradient between sunlight exposure and the number of suicides but they found a positive correlation between lack of sunlight and non-violent suicide cases.


Dawdy, P. (2004) One Suicide Too Many. Retrieved May 4, 2009 from http://www. seattleweekly. com/2004-01-14/news/one-suicide-too-many. php. Dawdy, P. (n. d. ) Suicide Watch. Retrieved May 4, 2009 from 3. http://www. seattlebusinessmonthly. com/ME2/Audiences/dirmod. asp?. Emundson, L. (2000). Seasonal Affective Disorder. Retrieved May 4, 2009 from http://serendip. brynmawr. edu/bb/neuro/neuro00/web1/Edmundson. html. Seasonal Affective Disorder. Retrieved May 4, 2009 from http://familydoctor. org/online/famdocen/home/common/mentalhealth/depression/267. html.