Psychomotor retardation in major depressive disorder: A dimension to be rediscovered?

Abstract

Psychomotor activity is one of the traits we most immediately perceive in others. Psychomotor slowing, which can be easily noticed on a first medical examination, is a symptom which may be prodromal of psychic disturbances.Historically, psychomotor retardation is a characteristic attached to depression, especially melancholia. Some studies show that psychomotor retardation is associated with good therapeutic prognosis, including positive response to electro-convulsivo-therapy. The cluster of non-verbal symptoms includes both basic aspects related to motor behavior such as attitudes and movements and more complex aspects such as goal-directed behaviors. We will see that this intuitive and fundamental dimension of clinical depression is not homogeneous. From a motor point of view, hypo-bradykinesia in depression may be compared to the one found in cortico-subcortical syndromes such as Parkinson's disease. This comparison suggests that key brain structures such as the basal ganglia could be involved in depression.Moreover, the loss of vital energy is the dominant psychopathological explanation linked to psychomotor retardation. From a phenomenological point of view, this interpretation seems to be relevant but appears disappointing as an experimental variable. However, motivation, understood as the factor that energizes the behavior seems to be an interesting and promising concept.Experimentally, it is possible to measure how much an individual is able to invest energy in order to achieve a goal.The impact of depression on the process of incentive motivation will be analyzed before turning to a description of therapeutic interventions related to psychomotor field such as sports or sensorimotor stimulations that appear to be promising tracks for clinical improvement.