Caffeine linked to decrease in depression
By Catherine Walker
Caffeine’s potential to reduce depression in women was explored in a new research initiative. Depression 
is a recurrent condition that affects more women than men.
In the U.S. depression is said to affect one in every five women during their lifetime.
The authors say that ‘the identification of risk factors for depression among women and the development of new preventive strategies are, therefore, a public health priority.
In this study, researchers set out to examine whether the consumption of caffeine or certain caffeinated beverages is associated with the risk of depression in women.
50,739 U.S. women who participated in the Nurses’ Health Study were studied by Michel Lucas, Ph.D., R.D., and his colleagues. Lucas is from the Harvard School of Public health.
The participants had an average age of 63, had no depression at the start of the study in l996 and were followed up until June 2006.
Caffeine consumption was measured by the investigators through questionnaires which were completed from May 1980 through to April 2004. The frequency that caffeinated and non-caffeinated coffee, non-herbal tea, caffeinated soft drinks (sugared or low-calorie colas), caffeine-free soft drinks (sugared or low-calorie caffeine-free colas or other carbonated drinks) and chocolate were usually consumed in the previous 12 months was also measured.
For the purpose of this stud, depression was identified by a new diagnosis of clinical depression and beginning regular use of antidepressants in the previous two years.
The researchers found that the risk for depression was less for women consuming four cups or more per day (a 20% decrease) and by those who consumed two to three cups per day (a 15% decrease).
Compared with women in the lowest categories of caffeine consumption (less than 100 milligrams per day), those in the highest category (550 mg per day or more) had a 20% decrease in their risk of depression.
It was noted that the consumption of decaffeinated coffee did not lower the risk of depression.
The authors write ‘In this large prospective cohort of older women free of clinical depression or severe depressive symptoms at baseline, risk of depression decreased in a dose-dependent manner with increasing consumption of caffeinated coffee.’
They also note that this observational study ‘cannot prove that caffeine or caffeinated coffee reduces the risk of depression but only suggests the possibility of such a protective effect.’
Further investigations to confirm their results and to determine whether usual caffeinated coffee consumption could contribute to prevention or treatment of depression is called for by the authors.
Source: JAMA and Archives Journals
