Caffeine
Studies of blood flow measurements suggest that caffeine did not activate the brain circuit of dependence in humans, but activated regions involved in attention, vigilance, and anxiety. These results confirm pre-clinical data reporting no involvement of the circuit of dependence in the physiological effects of caffeine. In other words, based on the results of studies that used brain mapping technology, caffeine does not fulfill the criteria to be described as a drug of dependence.
The American Psychiatric Association has indicated that more research is needed to determine the clinical significance of Caffeine Use Disorder before the diagnosis may be recognised in the DSM as a clinical disorder. Withdrawal symptoms such as headaches are associated with the habitual consumption of caffeine, independent of necessity, as well as daily dosage.
Long-term Coffee Consumption and Risk of Cardiovascular Disease: A meta-analysis, published in Circulation, concluded that moderate coffee consumption was associated with a lower risk of cardiovascular disease. It found that drinking 3-5 cups of coffee per day was linked to the lowest risk.
Coffee, Caffeine, and Risk of Depression Among Women: This study, published in JAMA Internal Medicine, suggested that drinking coffee may reduce the risk of depression in women. The researchers found that women who drank 2-3 cups of coffee per day had a 15% lower risk of depression compared to those who drank one cup or less per week.
Coffee Consumption and Risk of Stroke: A Meta-Analysis of Cohort Studies concluded that moderate coffee consumption was associated with a reduced risk of stroke. The study found that consuming 3-4 cups of coffee per day was linked to the lowest risk of stroke.
Coffee and Decaf Coffee in Relation to Incident Type 2 Diabetes Mellitus: A Systematic Review With Meta-Analysis found that both caffeinated and decaffeinated coffee consumption were associated with a reduced risk of type 2 diabetes. The risk reduction was more pronounced in those who consumed more coffee.
https://www.coffeeandscience.org/health/coffee-and-caffeine
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