Four related psychological studios were undertaken with parkinsonians on l-Dopa therapy for varying lengths of time to provide an assessment of their longer range psychological status (time on l-Dopa >2 years), particularly in comparison to the shorter range (time on l-Dopa <2 years) effects, A variety of psychological tests of cognitive-perception, emotional behavior, and perceptual arousal wero administered to indeponclont-oquatod groups of patients on shorter and longer range therapy and to equated control samples, It was found that longer range parkinsonians (on l-Dopa a mean of 2½ years) largely tended to maintain earlier increments in cognitive- perceptual functions, However, significant worsening of subjectively porcoived depression at that stage, as compared with the l-year status, was noted, Those effects were independent of ago, SOK, length of illness or stage and severity of disease, It is suggested that this increased depression is largely psychogonio in nature, and related to such life event variables as failure of the drug to cure the disease, continuing progression of symptoms and disability, and continuing need for constant medical treatment, In contrast, it is hypothesized that earlier cognitive-perceptual increments are maintained (at least up to 2½ years) due to the continuing increase in behavioral activation, and in turn are related largely to chemical events indicated by l-Dopa administration,