Depression and Parkinson's disease: a study of 135 parkinsonian patients

Depression and Parkinson's disease: a study of 135 parkinsonian patients. Objective: The prevalence of depression in Parkinson's disease (PD) raises the issues of the difficulties of diagnosing the condition and of the relationships between depression and the natural history of the disease. Methods: A cohort of 435 consecutive patients with idiopathic PD underwent psychiatric (DSM-III-R, Goldberg depression scale), neurological (distinguishing "axial" signs from other signs of parkinsonism), and neuropsychological (particularly frontal tests) evaluations, Results: Depression is present in more than half of the patients and it seems to be more frequent in patients with the akinetic and fluctuating forms of the disease. The subjects who are depressed do not have a greater degree of cognitive impairment, but their scores on frontal tests are higher. Moreover, the axial signs of the disease (postural instability, axial rigidity) are more severe in depressed parkinsomans suggesting a link between depression and the non-dopaminergic lesions of the disease. Even though slowness, appetite and sleep disturbances, and fatigue may be encountered in non-depressed parkinsonian patients, separation of the parkinsonian population into subgroups shows that certain symptoms are never seen in parkinsonians who are not depressed: it is thus evident that "the impression that life is not worth living", "the hopelessness", "the impression of being worthless and incompetent", "the low level of energy", "the morning sadness" are characteristic, of parkinsonian depression. Parkinsonian depression has two major clinical forms. The first one is associated with a greater number of somatic manifestations: sleep disturbances, morning fatigue, corresponding to more severe depression with hopelessness and loss of self confidence. The second exhibits few somatic manifestations with apathy and slowness as frequent complaints. Conclusions: This study defines the symptoms of parkinsonian depression which should be better recognised in order to be treated. The link between depression and axial signs of the disease may explain why L-dopa and dopaminergic agonists improve the motor signs of depression without influencing depressive manifestations in most cases.