Depression

Caffeine and Depression Research regarding the effects of caffeine in depression has been mixed. Some studies have found that caffeine can elevate mood in people with depression, while other research has shown that people who are heavy coffee drinkers are more likely to be depressed.

One of the reasons that caffeine has a varied effect on depression is because of the initial lift that a cup of coffee provides. Once that lift fades, a fall-off in mood occurs. Researchers at Kaiser Permanente witnessed an improvement in mood in people with long-term coffee consumption. The study followed 128,934 nurses and determined that the coffee drinkers were significantly less likely to commit suicide than non-coffee drinkers.

Another study replicated these results, reporting that coffee drinkers had a 58 to 66% decreased risk of committing suicide. Paradoxically, a symptom of caffeine addiction can be depression. In conclusion, the consumption of caffeine has been linked with both improvement and deterioration of mood. Based on these findings, people with depression may want to carefully monitor how caffeine affects their mood.

Anxiety

It should come as no surprise that caffeine has been associated with anxiety. Caffeine is believed to induce anxiety by blocking proteins called adenosine receptors on the surface of nerve cells in the brain. For those with any type of anxiety, all forms of caffeine should be avoided, including coffee, tea, chocolate, caffeinated sodas, and medications that contain caffeine. Moreover, people with high levels of anxiety appear to be more susceptible to the actions of caffeine.

Sleep Disorders

An often overlooked cause of insomnia is the use of stimulating beverages. Caffeine is a stimulant, the effects of which can last up to 20 hours, so some people will have disturbed sleep patterns even when their last cup of coffee or tea was in the morning. Sensitivity to the stimulant effects of caffeine varies greatly from one person to the next depending on how quickly the body can eliminate caffeine.

Even small amounts of caffeine may be enough to cause sleep disturbances in some people. Anyone experiencing sleep difficulties should avoid all caffeine-containing drinks such as coffee, tea, colas, cocoa and chocolate, especially in the evenings. Additionally, many over-the-counter drugs contain caffeine and stimulate the nervous system, making sleep more difficult.

Cognitive Function

Caffeine is associated with reducing cognitive impairment. In a study at London’s National Addiction Centre, higher levels of coffee consumption were associated with improved cognitive performance in seniors. Another study of 4,197 women and 2,820 men that were 65 years and over found that the "The psychostimulant properties of caffeine appear to reduce cognitive decline in women without dementia, especially at higher ages." The researchers felt that caffeine had potential use in prolonging the period of mild cognitive impairment prior to a diagnosis of dementia.

Parkinson's Disease

Scientists have suggested that caffeine can considerably reduce the risk of developing Parkinson's disease (PD). A study at the Department of Veterans Affairs in Honolulu found that higher caffeine intake is associated with a significantly lower incidence of Parkinson's. These findings do not suggest that caffeinated beverages should be used as a treatment for PD, but simply that caffeine may in some way help to prevent the development of the disease in its early stages.

A comprehensive examination of caffeine consumption at Harvard determined that moderate consumption of caffeine reduced the risk of Parkinson's among 47,351 men and 88,565 women. Men who drank four to five cups of coffee per day cut the risk of developing Parkinson's disease almost in half. Women who consumed between one and three cups of coffee per day cut their risk of nearly in half. Black or green tea would be a better choice of caffeinated beverages since it has neuroprotective properties that can decrease the risk of Parkinson's, without the risks associated with coffee. A study at the University of Athens and Harokopio University Drinking found that more than one cup of coffee a day increases the risk of heart disease by increasing cardiovascular inflammation.

When deciding whether or not to drink coffee of tea, an important consideration should be the advantages and disadvantages of each. Tea tends to be more of an antioxidant, and has been associated with health benefits whereas coffee has not.

References
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