A recent study frequented several headlines and teleprompters this week. Its claim: Chronic coffee consumption may ward off depression in women.
Though the work is one step in understanding caffeine's effect on mental health, there's reason to be cautious before reaching for that extra cup of joe. The authors point out the research's limitations and view the work as a place to launch more controlled studies on the topic, not to make recommendations to drink more coffee.
The analysis, which focused on 50,739 female nurses (average age of 63) in the Nurses' Health Study, relied on self-reports of coffee and caffeine consumption in other drinks and foods. Researchers began tracking the group in 1996 and stopped in 2006.
Before 1996, scientists made sure to include only women without depression or a history of it. Depression was defined as a clinical diagnosis and use of antidepressants. The researchers also had access to a variety of data, including the participants' smoking status, exercise habits, diet and other socioeconomic factors.
Within the 10-year frame, 2,607 women experienced clinical depression. Researchers compared this group with other women who did not experience the condition. By dividing participants into groups based on how often they consumed coffee (less than one cup per week, between two and six cups per week, between two and three cups per day, and so on), scientists could see if their coffee habits were associated with depression.
Women who drank more than four cups of coffee per day had one-fifth less of a risk of experiencing depression than women who consumed less than one cup per week. Those drinking two to three cups per day also had less of a risk — 15 percent or so less.
Depression poses challenges for men, too, but more women experience the condition each year in the United States, which is why the study still proves useful.
What else do researchers know about coffee consumption and mental health?
As a mood-altering chemical, caffeine has received considerable attention. One review suggests caffeinated coffee brings about different reactions in some people. For example, individuals living with panic or anxiety disorders were more likely to become more anxious — not less — after consuming the drink.
Another paper reported that consuming coffee made men and women with depression more anxious, indicating certain people may be more sensitive to the stimulant to begin with, too.
But the current research remains unique in its ability to track participants over a 10-year period. Even more, researchers have information about the women before they showed signs of depression.
But determining cause and effect can be difficult. It makes sense that people already experiencing sleeping problems, depression or anxiety might avoid coffee, which could explain why women without depression consume plenty of the drink.
Even if coffee lacks a special compound that lowers a woman's risk of experiencing depression, the findings still demonstrate the type of people who might be more drawn to the beverage.
It's also worth mentioning that too much caffeine — more than four cups of coffee per day — can cause sleeping disorders and may negatively affect central nervous system functions, according to the Mayo Clinic.
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