Chronic depression requires more intensive treatment than a single episode of depression, in part because it lasts longer and tends to be more severe, according to the December 2009 issue of the Harvard Mental Health Letter. In addition, some type of maintenance therapy may be needed to prevent relapse.

Depression is categorized as chronic when symptoms last at least two years. Clinical trials have shown that two types of antidepressants—tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs)—are equally effective for treating chronic depression. Between 45% and 55% of the study participants responded to antidepressant treatment, and no single drug emerged as better than the others. But only 25% to 35% of patients with chronic depression were able to achieve remission from the first drug they took, at least in the short term.

One possibility is that patients with chronic depression may need to take an antidepressant for an extended period before experiencing any benefit. And because long-term maintenance treatment with antidepressants reduces the risk of relapse, some clinicians recommend continuing drug treatment for six to 12 months to increase chances of achieving full recovery.

Dr. Michael Miller, editor in chief of the Harvard Mental Health Letter, reports that although few studies have looked at psychotherapy for chronic depression, most evidence supports a type known as Cognitive Behavioral Analysis System of Psychotherapy (CBASP). CBASPis based on the premise that patients with chronic depression think, behave, and communicate in ways that make traditional therapy difficult. They tend to focus on themselves and may be uncooperative. They also tend to view current situations either as a replay of a negative event in the past or a precursor to a similar situation in the future. CBASP therapy challenges these perceptions and behaviors.

Read the full-length article: "Managing chronic depression"