In parkinson's disease, depression is often a major problem but extra is required when prescribing antidepressants as they can interact with medication used in Parkinson's disease. SSRIs may increase the risk of serotonin syndrome when combined with the dopaminergic drug selegiline. Serotonin syndrome is a potentially life-threatening reaction that cause the body to have too much serotonin. Tricyclic antidepressants are poorly tolerated because of their anticholinergic effect which may compound anticholinergic drugs used in Parkinson's disease.