Posted on Tue, 24 Aug 10
Caffeine is the most widely consumed psychoactive drug in the world yet its effects on mood and anxiety are still unclear. Some people claim caffeine improves their mood while others find the opposite. Both are right.
High doses of caffeine (over 300 mg) can cause feelings of anxiety, restlessness and nervousness in sensitive individuals. High doses of caffeine may also make people with existing anxiety disorders worse.
On the other hand caffeine can improve mood, alertness, attention and energy. The positive effects of caffeine on mood occur at lower doses (50-100 mg) and may be limited to regular caffeine users. Genetic differences also play a role in how caffeine affects you.
People with a difference in a gene that affects caffeine activity in the brain are more likely to feel anxious in general and are particularly sensitive to caffeine. This may explain why some people tend to naturally avoid it.
In short, caffeine may be beneficial for people with low mood or energy at low doses (50-100 mg a day or about 1-2 cups of tea, or a coffee) and detrimental for people with anxiety, particularly if you are sensitive to caffeine or consume high amounts (300 mg or about 3-4 cups of tea or 2-3 cups of coffee).
Lara DR. Caffeine, mental health, and psychiatric disorders. J Alzheimers Dis. 2010;20 Suppl 1:S239-48.