Caffeine may contribute to agitation, irritability, and possibly interfere with anti-psychotic medications. On the other hand, caffeine can markedly elevate blood levels of antipsychotic medications, increasing the probability of adverse effects. The possible mechanism explaining this finding is that caffeine and antipsychotic medications both compete for metabolism at the hepatic P450 isoenzyme system. Patients with bipolar disorder are at risk for an exacerbation of manic symptoms when they consume large amounts of caffeine. This is due both to its direct psychostimulant properties and secondary to increase renal excretion of lithium.
Severe depression is correlated with high blood-caffeine levels.
People with panic disorders may consciously decrease caffeine use. Diagnosis of any caffeine-related disorder begins with clinical awareness. Beverage caffeine is such a common component of social activity that its consideration as a psycho-stimulant is often neglected. Too many clinical histories fail to record caffeine use. A complete caffeine history tabulates doses from beverages and medications.