Akathisia has previously been reported to exacerbate psychopathology and to be associated with noncompliance, suicidality, and violence. One previous study found brisk decrements in psychopathology after acute treatment of akathisia with intramuscular biperiden. This study assessed changes in akathisia and psychopathology in 19 patients after separate one-day treatments with intramuscular benztropine and oral propranolol. Benztropine and propranolol led to clinically meaningful and statistically significant decrements in ratings of subjective and objective measures of akathisia and in psychopathology scores. Changes in psychopathology correlated significantly with changes in subjective measures of akathisia after benztropine and with subjective and objective measures of akathisia after propranolol. Changes in akathisia accounted for 9%-42% of the variance in changes in psychopathology. After treatment, statistically significant decrements in Brief Psychiatric Rating Scale (BPRS) positive symptoms were noted, and individual items not directly related to the akathisia syndrome, such as conceptual disorganization, hallucinatory behavior, and unusual thought content declined, although not significantly. These findings, taken together with the results of a similar previous study, indicate that the effect of akathisia in exacerbating psychopathology is large. If suspected, akathisia should be treated promptly.