Caffeine is the world’s most widely used stimulant and most of it comes from coffee. Coffee has been studied extensively and we know that it does not have an overall effect on cardiovascular disease. And it does not have great impact in reducing breast and oesophagal cancers. But what about coffee and mental health?
In this week’s Archives of Internal Medicine is a study looking at exactly that. Depression is a chronic illness with twice as many women being affected. In this study more than 50,000 women who were free of depression at the start of the study were followed for 10 years to look at the relationship between depression and caffeine. Interestingly, regular coffee drinkers compared to women who drink caffeine less frequently were more likely to drink more alcohol, be current smokers and less likely to be involved as volunteers or in community groups. They also had less obesity less blood pressure issues and diabetes.
Most of the caffeine consumption came from coffee — about 82 per cent. What the researchers found was the coffee drinkers with more consumption had less depression. Those who drank decaf did not show this association and in fact higher decaf consumption showed higher rates of depression. No association was found from caffeine from other sources. To be specific, those who drank 2 to 3 cups of caffeinated coffee had a 15% decrease in depression, and those with 4 cups had a 20% decrease in depression
Other studies have seen less suicide risk in coffee drinkers up to six to seven cups a day but increasing with eight cups or greater. Coffee at tolerable doses can improve psychomotor performance, increase vigilance and give more energy and a sense of wellbeing. But beyond that dose comes the reverse effect. Typically, you can find what amount you can tolerate. We think caffeine works in the brain through its impact on a brain chemical called dopamine but it might influence serotonin as well. Overall, I don’t think you will find your doc advising you to rev up the caffeine to decrease your risk of depression, but it is an interesting thought that this could be prevention or treatment of depression!