Anxiety and depression in Parkinson's disease.

OPINION STATEMENT: Anxiety and depression, while very common problems in Parkinson's disease (PD), have not been subject to adequate treatment trials. While a handful of double blind placebo-controlled trials of depression have been published, only a small number of subjects have been enrolled in most of these. There have been no adequate treatment trials of anxiety. Thus, most practitioners base their treatments on what has been published in the general population and their own personal experience. The data suggest that depression is probably treatable in some cases, but there are no data to support any drug treatment of anxiety. Much of the rationale for treating these disorders is based primarily on side effect profiles rather than efficacy and is almost entirely based on anecdotal experience. Although we lack convincing data, we do believe in the pharmacologic treatment of depression and anxiety and choose medications based on side effect profiles, some of which may be useful. We favor the selective serotonin reuptake inhibitors (SSRIs) in general for both depression and anxiety because of their relative freedom from side effects but will often choose mirtazapine if insomnia or weight loss is a problem, clonazepam for anxiety without depression if an SSRI is insufficient or if REM sleep behavior disorder is a problem, or a tricyclic antidepressant if drooling is troubling and the patient is not demented. Alternatively, we use the serotonin and noradrenaline reuptake inhibitor venlafaxine in those who do not tolerate an SSRI. SSRIs cannot be used for anxiety on an as needed basis, whereas short-acting benzodiazepines may be useful for this purpose. Psychosocial treatments of both depression and anxiety have also been under-studied, with probable benefits and a benign adverse effect profile.