Motor alterations in depression and anxiety disorders: A systematic review and meta-analysis

Background: Psychomotor retardation has long been recognized as a major feature of depression, and anxiety disorders have been linked with freeze and flight motor responses. This systematic review and meta-analysis aimed a) to synthesize available evidence of motor alterations comparing individuals with depression and anxiety disorders to healthy individuals and b) to evaluate the effect of experimental manipulations of motor displays within these clinical groups. Method: The databases PubMed and PsycINFO were searched for studies either assessing motor differences between clinical and healthy control groups or manipulating the motor system within a clinical group. Results: The literature search yielded 87 relevant papers, comprising 82 studies comparing a clinical group to a healthy group and 5 studies investigating motor manipulations within a clinical sample. The results of the meta-analysis (K = 71) indicated a statistically significant combined estimate of differences between healthy and clinical groups (g = 0.38 [0.31, 0.45], adjusted for publication bias g = 0.26 [0.19, 0.33]) of a small size. This effect did not vary according to type of disorder (anxiety vs. depression, p =.468). From a narrative review of experimental studies within clinical groups, four out of five studies reported statistically significant effects of manipulating the motor system on affective outcomes. Discussion: This synthesis adds to the accumulating empirical evidence of motor alterations in depression and anxiety disorders. Future research will need to investigate how individuals suffering from depression or anxiety disorders could benefit from psychological, behavioral, and physical interventions directly aimed at the motor system.