Researchers from Fudan University analyzed health data from 461,586 individuals using the UK biobank data. Participants were free from mental health conditions at the start of the study, and were followed for a median of 13.4 years, with their coffee consumption recorded at baseline.
The research team examined how different levels of coffee intake were associated with the later development of mood and stress-related disorders.
The analysis revealed a “J-shaped” relationship between coffee consumption and mental health risk.
This suggests that compared to people who did not drink coffee, moderate consumption of 2 to 3 cups per day was associated with the lowest likelihood of developing conditions such as anxiety or depression.
Tom Maclaren, BMBS, a consultant psychiatrist at Re:Cognition Health, who was not involved in the study, spoke to Medical News Today about 2 to 3 cups of coffee potentially being the optimal amount for the most benefit:
“In clinical practice, we often see that moderate stimulation can support mood and functioning, while higher levels of caffeine tend to increase anxiety, irritability, and sleep disruption. A J-shaped pattern is therefore very consistent with how patients respond in real life.”
“Two to three cups is often enough to improve alertness, concentration and energy without triggering the physiological stress response that comes with higher doses.”
— Tom Maclaren, BMBS
However, by contrast, higher consumption appeared less beneficial. Drinking 5 or more cups daily was linked to an increased risk of mental disorders, suggesting that higher intake may negate the possible health benefits.
“Once intake becomes excessive, the same stimulant effect that initially feels helpful can start to worsen tension, restlessness, and poor sleep, which in turn affects mental health,” Maclaren added.
Notably, this association was consistent across different types of coffee, including ground, instant, and decaffeinated varieties.
Although the study did not directly measure brain changes that could explain this relationship, the researchers suggest that coffee’s bioactive compounds may play a role.
Previous research suggests that these compounds may possess antioxidant, anti-inflammatory, and neuroprotective properties. As such, these compounds likely influence brain pathways involved in mood regulation.
“Moderate caffeine intake influences brain chemicals linked to mood and motivation, particularly dopamine,” Maclaren told MNT.
“[Caffeine] also reduces fatigue and may support cognitive function, which can indirectly improve mood. At the same time, coffee contains compounds with anti-inflammatory effects, and inflammation is increasingly recognised as playing a role in depression.”
— Tom Maclaren, BMBS
Additionally, the study authors also conducted a genetic analysis. They attempted to identify individuals whose genes would suggest they may be better or worse at processing caffeine. However, they found that these differences did not significantly alter the observed associations.
Moderate coffee consumption has previously been associated with a range of potential health benefits, including reduced risk of cardiovascular disease and improved longevity. These new findings suggest that it could also form part of a broader lifestyle approach to supporting mental well-being.
While the results are encouraging for regular coffee drinkers, the study authors emphasize moderation.
The potential benefits were strongest at 2 to 3 cups, which is consistent with previous research. The study also highlights diminishing or adverse associations at higher levels of coffee intake.
“Rather than making drastic changes, the study reinforces the value of moderation,” Maclaren adds.
“People drinking more than four or five cups a day, especially if they experience anxiety or poor sleep, may benefit from gradually reducing their intake and noticing whether their symptoms improve.”
— Tom Maclaren, BMBS
Maclaren also highlighted that the large prospective study shows association, not causation. He also noted that many variables could be at play, such as individual tolerance and coffee habits, which make it difficult to isolate coffee as an independent factor.
While further research is still necessary to determine whether coffee directly reduces the risk of mental health conditions, current evidence suggests that a moderate daily coffee habit may be compatible with, and possibly supportive of, good mental health.
