The Benefits and Risks of Caffeine

Caffeine is the most commonly used psychoactive substance in the world, and after millennia of use we are now discovering that tea and coffee may have many beneficial effects for our mental health.

Coffee cultivation and consumption goes back over 1200 years, and has its roots in Ethiopia and Yemen. Today, coffee is the second largest globally traded commodity, second only to oil. Tea became popular in China around 3rd century AD and before that was likely consumed as food and medicine, known to sharpen the mind.  Tea spread over the Asian continent, and was reserved for royalty and religious ceremonies for hundreds of years; it helped keep Buddhist monks alert during meditation.

Currently, more than 183 million people drink coffee on daily basis, and 173 million more drink tea.  In 2012 this amounted to $18.7 billion dollars in combined coffee and tea sales. More than half of adults aged 25- 39 report drinking coffee daily. The success of coffee and tea suggest that there must be something to it. A wave of recent scientific studies is demonstrating that drinking coffee and tea has many beneficial effects, and some harmful ones, on our brains and mental health.

Drinking Coffee Protects from Depression

Good news for coffee lovers – a study published in April 2014 in PLOS One revealed that tea and coffee drinkers have lower risk for depression.  In the study 263,923 participants over the age of 50 reported on their use of various types of beverages in 1995-1996.  In 2000 researchers followed up and collected information about diagnoses of depression in the study group.

The study found that:

  • Individuals who consumed four or more soft drinks per day had a 30% higher rate of depression than those drinking none.

  • Those drinking four or more fruit drinks fared even worse with 38% higher rates of depression.

  • Coffee drinkers were 10% less likely to develop depression overall.

  • Drinking tea had no impact on depression rates.

The study also found that diet soft drinks and fruit drinks were more likely to be associated with depression than regular drinks. This raised a particular concern about the potential for diet sweeteners to contribute to depression.

Overall, based on this study, drinking coffee or tea without any sweetener is associated with lower risk for depression.  Adding artificial sweeteners to beverages increases risk for depression.  Adding sugar or honey did not increase depression risk.  So if you must add something sweet to your beverages, it is best to stick with the natural sweeteners.

Additional Benefits of Coffee for Mental Health

A review article published in 2010 describes that in addition to decreasing the risk for depression, drinking coffee in moderation (<6 cups per day) may have a number of other benefits for brain health, including:

  • lower risk for Parkinson’s disease

  • lower risk for dementia

  • increased alertness, attention and cognitive function (especially in longer tasks of situations of low arousal)

  • elevated mood

  • lower risk of suicide

  • possible beneficial effects in ADHD

  • possible beneficial effects in OCD

Much more research is needed to understand whether it is caffeine or some other factor related to drinking coffee is responsible for the health benefits. The benefits that coffee drinkers seem to enjoy compared to non coffee drinkers may be related to what isn’t being consumed rather than to coffee itself.  In two large studies, the Nurses’ Health Study and the Health Professionals Follow-Up Study, scientists linked the consumption of at least one soda per day to a 16% increased risk for stroke.  When soda was replaced with coffee, the risk for stroke dropped by 10%. The consumption of soda and other sugary beverages is also linked to diabetes, obesity, and heart disease, so by replacing these drinks with coffee, some health benefit is almost certain to occur.

The Risks

The bad news is that caffeine can have harmful effects such as:

  • addiction to caffeine

  • anxiety

  • though it is very rare, caffeine can induce mania or psychosis when consumed at high doeses

Most coffee drinkers are familiar with the addictive qualities of caffeine, and have experienced the unpleasant sensation of caffeine withdrawal with headaches, lethargy and other symptoms when they do not get their usual dose of caffeine.

While some individuals tolerate coffee very well, others are quite sensitive to it. Individuals with panic disorder and social anxiety are particularly sensitive to the anxiety producing effects of caffeine.

General Health Benefits of Coffee

In addition to the benefits for brain health, coffee also has benefits for physical health.  Coffee drinkers, compared to nondrinkers, may be less likely to develop:

  • Type II diabetes,

  • Stroke

  • Endometrial, Hepatocellular, Colorectal and Premenopausal Breast Cancer

  • death from any cause

Though too much coffee can make you feel as if your heart is beating faster, ultimately, coffee has a neutral effect on cardiovascular health.


Drinking tea and coffee, especially unsweetened, may have a number of benefits for brain health and for general health.  Replacing soda, fruit drinks, and any drinks sweetened with artificial sweeteners with tea and coffee will reduce risk for depression, suicide, and neurodegenerative disorders.  Caffeinated drinks also have risks, especially for those with anxiety, and they can be addictive.