The effects of antidepressants on obstructed and unobstructed gait in healthy elderly people

Background. Elderly patients treated with antidepressants for depression ar e at high risk for injury due to falling. The primary purpose of this study was to determine the effects of amitriplyline, desipramine, and paroxetine on the gait of healthy elderly subjects during unobstructed and obstructed (i.e., stepping over obstacles) gait. Psychomotor and mood tests were also performed. Methods. A randomized, crossover, four-period, double-blind, placebo-contro lled laboratory trial was performed. Twelve healthy elderly subjects (avera ge age, 67 years; range, 65-72 years) were tested. Subjects were assigned t he three antidepressant drugs or a placebo in a random order. Single doses of amitriptyline 50 mg, desipramine.50 mg, par oxetine 20 mg. or placebo we re given 4 hours prior to gait testing. Temporal-distance measures and kine matics of the lower trailing limb (i.e., Limb going over obstacle last) wer e obtained. Results. Compared with placebo, amitriptyline significantly reduced gait ve locity by as much as 8.08 (p =.028), cadence by as much as 4.9% (p =.012), angular velocity of hip flexion by as much as 10.0% (p =.004, and angular v elocity of knee flexion by as much as 8.3% (p =.018) during the crossing st rides when stepping over obstacles. Except for knee flexion angle, unobstru cted gait was not affected. Amitriptyline affected integrative capacity of the central nervous system (CNS) and ability to concentrate as measured by psychomotor and mood tests. Conclusions. The results for amitriptyline suggest that the subjects slowed their obstacle crossing speeds as a result of reduced CNS integrative capa cities. Neither paroxetine nor desipramine significantly affected gait, psy chomotor function,or mood.