Retardation in depression: assessment by means of simple motor tasks.

Background: Psychomotor retardation in depression has mostly been assessed with tasks requiring both cognitive and motor processes. This study tested whether retardation could be measured if the cognitive demands of the task were minimal.
Methods: 30 inpatients with a major depressive episode were compared one week after the start of antidepressant treatment, to 30 healthy control persons, matched for age, sex and educational level. Tests consisted of ten simple drawing tasks. The kinematics of drawing movements were recorded using a specially designed pen, a graphics tablet and a personal computer.
Results: Patients showed marked motor slowing on all the tasks: longer movement durations, longer pauses and lower velocities.
Conclusions: Psychomotor retardation in depressed patients treated with antidepressants occurs during drawing tasks, in which the cognitive demands are minimal and less than those required in the figure copying tasks used in our previous studies.
Limitations: The use of co-medication can have influenced the results, although no correlations were found between the use of medication and the kinematic variables.
Clinical Relevance: Detailed registration and analysis of drawing movements enable a more precise diagnosis of psychomotor disturbances in depressed patients.