In the DSM IV-TR, psychomotor delay is one of the 9 core symptoms identified to find major depressive disorder (MDD).
Although psychomotor delay has long been identified in MDD, its characterization and clinical significance are not well understood. A synthesis of the literature on psychomotor delay in depression was recently undertaken to increase knowledge and understanding of this component to improve diagnosis, with the goal of increasing awareness among clinicians. PubMed database searches led to a total of 154 articles with studies dating from 1936-2010. In patients with psychomotor retardation, there are marked speech abnormalities, such as longer pauses and decreased speech volume. Characteristic eye movements are a fixed gaze and poor maintenance of eye contact. Another characteristic sign is overall psychomotor slowing, including hand, leg, torso, and head movements, slumped posture, and increased self-touching, especially of the head.
The basal ganglia appear to play a key role in psychomotor slowing in mood disorders, and neuroimaging and neurophysiology studies suggest decreased dopaminergic function in specific brain areas. Drawing tasks are frequently used to assess psychomotor delay, and other tests measure both motor and cognitive aspects of psychomotor delay. The three main psychomotor retardation rating scales that we have at present are the Salpetriere Retardation Rating Scale (SRRS), the Motor Agitation and Retardation Scale (MARS), and the CORE Measure. Studies of different types of antidepressant medications (selective serotonin reuptake inhibitors, tricyclics, serotonin-norepinephrine reuptake inhibitors, norepinephrine-dopamine reuptake inhibitors, monoamine oxidase inhibitors) in patients with psychomotor retardation are inconclusive. However, the available data suggest that depressed patients with psychomotor delay may respond well to electroconvulsive therapy.
The many studies currently focusing on this aspect of MDD should improve our knowledge of the pathophysiology of MDD and its diagnosis, and improve the quality of its treatment.