Drink Coffee, Stay Happy?
4 Cups Daily Linked With 20% Lower Risk of Depression in Women, but Mental Health Expert Urges Caution
Caffeine and Depression Risk continued...
What could explain the link? Ascherio cannot say for certain."We know for certain caffeine gets into the brain. It activates several neurotransmitters related to depression." Among them, he says, are dopamine and serotonin.
That happens short-term, he says. How that affects the risk of depression long-term is not known, he says.
Other research has found a link between coffee drinking and lower risk of Parkinson's disease and diabetes, Ascherio says.
The new findings are consistent with some earlier research. He says one study found suicide risk is lower among those who drink more coffee. A previous study by others found that men who drink coffee have lower risks of depression.
Although the study was well conducted, it has built-in limitations because it is observational, says Riba, past president of the American Psychiatric Society. The researchers simply looked at behaviors and then evaluated any associations.
"They are not saying cause and effect," she says.
With a group as large as the 50,000 studied by Ascherio, she says, the associations found can often disappear when the researchers look more closely.
"If we could prevent 20% of people from having depression, that would be terrific," Riba tells WebMD. "We have to continue to watch and follow this [research]."
Meanwhile, she cautions those with mood disorders to seek medical attention.
In an editor's note, Seth A. Berkowitz, MD, of the journal, writes: "This study makes an important contribution because it is, to my knowledge, the first large-scale study of coffee consumption to evaluate a mental health outcome in women."
He notes that other studies have found modest effects of caffeine on inflammation, no overall effect on heart disease, and perhaps modest protection against some cancers.
However, he adds that ''it seems premature to recommend coffee consumption" until research that looks at cause and effect is done.
The study was funded by the National Institutes of Health and the National Alliance for Research on Schizophrenia and Depression.