Comorbid psychiatric disorders in late life depression.

In late life depression, common comorbid psychiatric disorders are alcohol use, anxiety, and personality disorders. Elderly depressed patients are three to four times more likely to have an alcohol use disorder compared with nondepressed elderly subjects, with a prevalence of 15%-30% in patients with late life major depression. While the presence of a comorbid alcohol use disorder may worsen the prognosis for geriatric depression, limited data suggest that successful treatment of depression combined with reducing alcohol use leads to the best possible outcomes. Most studies show that the overall prevalence of anxiety disorders, particularly panic disorder and obsessive-compulsive disorder, is low in geriatric depression, but generalized anxiety disorder may not be uncommon. It remains unclear if the presence of a comorbid anxiety disorder impacts on the treatment and prognosis of late life major depression. Personality disorders occur in 10%-30% of patients with late life major depression or dysthymic disorder, particularly in patients with early onset depressive illness. Cluster C disorders, including the avoidant, dependent, and obsessive-compulsive subtypes predominate, while Cluster B diagnoses, including borderline, narcissistic, histrionic and antisocial, are rare. Overall, the research database on comorbid psychiatric disorders in major and nonmajor late life depression is relatively sparse. Since comorbid psychiatric disorders affect clinical course and prognosis, and may worsen long-term disability in late life depression, considerably more research in this field is needed.