Among eighty-three hospitalized adult psychiatric patients, 22% reported being high caffeine consumers (750 mg or more per day); these patients scored significantly greater on the State-Trait Anxiety Index and the Beck Depression Scale than moderate and low consumers. High consumers described significantly more clinical symptoms, felt that their physical health was not as good, and reported greater use of sedative-hypnotics and minor tranquilizers. Since caffeine modifies catecholamine levels, inhibits phosphodiesterase breakdown of cyclic AMP, and sensitizes receptor sites, association of caffeinism with both anxiety and depressive symptoms is possible.