Coffee and Depression – What Does the Research Say?
If you struggle with depression, it pays to get serious about your physical health. Fanatical, even. Regular vigorous exercise, a healthy diet, good sleep hygiene, and limited (ideally zero) alcohol intake are all excellent habits to develop.
What about coffee? And caffeine in general?
About half of us drink coffee every day. (The percentage varies by country and culture, with Europe and the Americas near the top.) I’m in that half, so naturally, I’ve wondered if and how it affects depression.
Fortunately for us coffee lovers, most research leans toward the view that moderate coffee consumption can be beneficial for depression. There are some areas of concern, mentioned below, but overall there’s no reason to worry about the morning coffee habit.
Disclaimer: I’m not a medical doctor, trained therapist, or nutritionist, just a longtime depression sufferer with an inquisitive mind. Please do not treat anything on Smash Depression as medical advice. Be skeptical of anything you read online, and get a second (or third or fourth) opinion.
Positive Studies on Coffee and Depression
Women in the study who drank two to three cups of caffeinated coffee a day were 15 percent less likely to develop depression over 10 years compared to those who drank one cup of coffee or less per week.
The researchers cautioned, however, that the new study only shows an association between coffee consumption and depression risk, and cannot prove that drinking coffee reduces the risk of depression in women.
World Journal of Biological Psychiatry
A similar study published in 2023 in the World Journal of Biological Psychiatry analyzed long-term data from 200,000 subjects and found: An association between drinking a few cups of coffee a day and a lowered — in fact, halved — the risk of suicide in both men and women.
“Unlike previous investigations, we were able to assess the association of consumption of caffeinated and non-caffeinated beverages, and we identify caffeine as the most likely candidate of any putative protective effect of coffee,” lead researcher Michel Lucas, a research fellow in the Department of Nutrition at HSPH, said in a press statement.
The study reveals coffee’s ability to protect the brain as a mild antidepressant. The caffeine in coffee not only stimulates the nervous system, but also enhances the production of certain neurotransmitters in the brain including serotonin, dopamine, and noradrenaline.
Chinese Researchers in Australian and New Zealand Journal
A recent meta-analysis conducted by Chinese researchers published in the Australian and New Zealand Journal of Psychiatry reached similar conclusions.
The researchers found a linear relationship between coffee consumption and depression risk, with a dose-response relationship of 8% reduced risk for each cup consumed per day. Additionally, they observed a nonlinear relationship between caffeine intake and depression risk, in which “the risk of depression decreased faster and the association became significant when the caffeine consumption was above 68 mg/day and below 509 mg/day.”
Although researchers are not certain about the mechanisms driving the link between depression and coffee or caffeine consumption, several potential explanations have emerged. Previous findings have implicated inflammation and oxidative stress in the pathophysiology of depression, and one possibility is that the various chemicals present in coffee in significant amounts — including chlorogenic acid, nicotinic acid, trigonelline, quinolinic acid, tannic acid, pyrogallic acid — have anti-inflammatory and antioxidant effects that impact depression.
Molecular Nutrition & Food Research
Yet another recent meta-analysis published in Molecular Nutrition & Food Research likewise found:
That consumption of coffee was associated with a lower risk of depression. The dose-response analysis identified a J-shaped association between coffee consumption and the risk of depression, with a decreased risk for consumption of up to about 600 mL/day.
Results from this meta-analysis showed that coffee consumption acts as an independent protective factor for depression and similar effects may be shared by tea.
This study’s “Discussion” section notes that “the mechanisms underlying the favorable association between coffee and tea consumption and depression are largely unknown” but offers some informed speculation.
The general trend of these studies: moderate daily coffee drinking can be beneficial, though researchers don’t know exactly why.
Concerns Over Coffee Drinking
There are a few legitimate concerns over coffee drinking for those prone to depression.
- These studies all looked at moderate coffee consumption, roughly around 2 to 3 cups per day. Several studies cited an upper limit beyond which more coffee drinking ceased to have a positive effect. The second article linked above mentioned that “a previous Finnish study found a correlation between drinking eight or nine cups every day and a higher risk of committing suicide.” So don’t overdo it.
- Coffee drinking can heighten anxiety. Many people suffer from both depression and anxiety. If you’re in both groups and caffeine makes you nervous, agitated, or irritable, be careful.
- Caffeine can impede your ability to fall asleep. Getting a good night’s sleep is enormously important to fighting depression. Treat sleep as sacred. For the sake of proper sleep hygiene, avoid caffeine for 6 hours before going to bed. If you go to bed at 10:00 pm, absolutely no coffee or caffeinated tea after 4:00 pm.
- Coffee may contribute to dehydration (though some recent reports dismiss that as a myth). Dehydration can contribute to bad moods, headaches, and fatigue. To be safe, make sure to balance your coffee drinking with plain old water.