Depression affects almost half of individuals with Parkinson’s disease (PD) during the course of their disease. Although depression is highly prevalent, it is frequently overlooked. There are several confounding factors hindering the diagnosis. A number of depressive symptoms overlap with motor and cognitive symptoms of PD. These include motor features such as slow movements, stooped posture, lack of facial expression; cognitive features such as diminished attention, mental slowing and other non-motor symptoms such as apathy (lack of subjective suffering in depression), anxiety (which can accompany depression) and psychosis (such as nihilistic delusions, which is mood-congruent with depression).

Depression in PD ranges from mild dysthymia to major depression. Features of depression in PD are partly different than those seen in Major Depressive Disorder. There is relatively low frequency of guilt, self-blame and worthlessness, whereas there is greater anxiety, feeling of panic, sad mood, pessimism and dysphoria. Suicidal ideation is less common, and actual suicidal behavior is rare. Somatic complaints are more common; there is high association with sleep disturbances, sexual dysfunction and fatigue.

Etiology of depression in PD is multi-factorial, including disease-intrinsic factors as well as a multitude of individual and psycho-social variables, such as underlying genetic vulnerability, occurrence of life events and individual coping abilities. Family history of depression, personal history of depression and lower education levels contribute to an enhanced risk. PD is characterized by degeneration in ascending monoaminergic modulatory pathways which also modulate mood. There is biochemical, pathological and functional imaging evidence for dopaminergic, noradrenergic and serotoninergic dysfunction. Management of depression in PD includes psycho-social interventions, psychotherapy including behavioral-cognitive treatment and medication. Treatment choice should be based on age, symptom profile, cognitive status and severity of depression.

Depression significantly affects the quality of life both for patients and their families. It is important to assess the presence of depression at every visit with leading questions and when indicated by appropriate scales. After all one can not find what one does not look for!...

Murat Emre, M.D. presented at the Fifth World Parkinson Congress in Kyoto, Japan and at the First and Second World Parkinson Congresses. He is currently an Adjunct Professor of Neurology at the Istanbul Faculty of Medicine, Department of Neurology, and he started the Behavioural Neurology and Movement Disorders Unit at Istanbul University.

Ideas and opinions expressed in this post reflect that of the authors solely. They do not reflect the opinions or positions of the World Parkinson Coalition®