According to a 2011 literature review, caffeine use may induce anxiety and panic disorders in people with Parkinsons disease. At high doses, typically greater than 300 mg, caffeine can both cause and worsen anxiety. For some people, discontinuing caffeine use can significantly reduce anxiety.In moderate doses, caffeine has been associated with reduced symptoms of depression and lower suicide risk. Two reviews indicate that increased consumption of coffee and caffeine may reduce the risk of depression.Some textbooks state that caffeine is a mild euphoriant, while others state that it is not a euphoriant.Caffeine-induced anxiety disorder is a subclass of the DSM-5 diagnosis of substance/medication-induced anxiety disorder. Reinforcement disorders
Addiction
Whether caffeine can result in an addictive disorder depends on how addiction is defined. Compulsive caffeine consumption under any circumstances has not been observed, and caffeine is therefore not generally considered addictive. However, some diagnostic models, such as the ICDM-9 and ICD-10, include a classification of caffeine addiction under a broader diagnostic model. Some state that certain users can become addicted and therefore unable to decrease use even though they know there are negative health effects.Caffeine does not appear to be a reinforcing stimulus, and some degree of aversion may actually occur, with people preferring placebo over caffeine in a study on drug abuse liability published in an NIDA research monograph. Some state that research does not provide support for an underlying biochemical mechanism for caffeine addiction. Other research states it can affect the reward system. "Caffeine addiction" was added to the ICDM-9 and ICD-10.
According to a 2020 study in the United States, coffee is the major source of caffeine intake in middle-aged adults, while soft drinks and tea are the major sources in adolescents. Energy drinks are more commonly consumed as a source of caffeine in adolescents as compared to adults. Beverages
Coffee
The worlds primary source of caffeine is the coffee "bean" (the seed of the coffee plant), from which coffee is brewed. Caffeine content in coffee varies widely depending on the type of coffee bean and the method of preparation used; even beans within a given bush can show variations in concentration. In general, one serving of coffee ranges from 80 to 100 milligrams, for a single shot (30 milliliters) of arabica-variety espresso, to approximately 100–125 milligrams for a cup (120 milliliters) of drip coffee. Arabica coffee typically contains half the caffeine of the robusta variety. In general, dark-roast coffee has very slightly less caffeine than lighter roasts because the roasting process reduces caffeine content of the bean by a small amount. Tea
Tea contains more caffeine than coffee by dry weight. A typical serving, however, contains much less, since less of the product is used as compared to an equivalent serving of coffee. Also contributing to caffeine content are growing conditions, processing techniques, and other variables. Thus, teas contain varying amounts of caffeine.Tea contains small amounts of theobromine and slightly higher levels of theophylline than coffee. Preparation and many other factors have a significant impact on tea, and color is a very poor indicator of caffeine content.