Dysthymic disorder (DD) denotes chronic depression with fewer symptoms than major depressive
disorder (MDD), and it affects ~ 2-4 % of adults with a similar prevalence in the elderly. In
the elderly, dysthymic disorder (DD) has been shown to be associated with suffering and
disability. The differences between young adult and elderly DD patients indicate that
findings obtained in young adults with DD cannot be extrapolated to elderly DD patients who
need to be studied separately. Data from epidemiologic studies support this view. In contrast
to the data in young adult DD patients, there is a paucity of controlled data on the
treatment of elderly DD patients. In our center, a double-masked, placebo-controlled study of
91 elderly DD patients did not find significant superiority for fluoxetine over placebo with
response rates of 27.3% for fluoxetine and 19.6% for placebo in intent-to-treat analyses, and
response rates of 37.5% for fluoxetine and 23.1% for placebo in completer analyses. Given the
relative failure of selective serotonin reuptake inhibitor (SSRIs) to treat geriatric DD
effectively, the investigators decided to evaluate the dual reuptake inhibitor, venlafaxine.
The investigators earlier completed an investigator-initiated, open-label 12-week venlafaxine
(Effexor XR) trial. Of 23 elderly DD patients, 18 completed the trial. Fourteen (60.9%) were
responders in intent-to-treat analyses with the last observation carried forward, and 77.8%
were responders in completer analyses. Nearly half the sample (47.8%) met criteria for
remission. In the intent-to-treat sample, increased severity of depression at baseline was
associated with superior response and the presence of cardiovascular disease was associated
with poorer response. These results with venlafaxine indicate that further treatment studies
of dual serotonin-norepinephrine reuptake inhibitors like duloxetine are warranted in elderly
patients with dysthymic disorder.