Although there are a significant number of medical therapies available for use in depression, treatment remains inadequate in many patients. Studies have shown that up to 85 percent of patients experience a recurrence sometime during their lifetime, and 50 percent will have a recurrence within two years of the initial episode. The goal of the first six to eight weeks of treatment is symptom relief. However, therapy should continue for an additional four to nine months to allow for more complete resolution of the episode and to prevent relapse. The need for long-term maintenance therapy depends on the number of previous episodes. Melfi and colleagues evaluated whether adhering to the current treatment guidelines reduces the likelihood of relapse or recurrence in patients with a history of depression.

Patients eligible for the study had a diagnosis of depression as identified by a review of state Medicaid records from 1989 to 1994. Only patients who had taken a tricyclic anti-depressant (TCA) or a selective serotonin reuptake inhibitor (SSRI) were included in the study. Three groups of patients were identified: those who filled fewer than four prescriptions during the acute treatment period; those who switched agents or added a second antidepressant; and those who filled four or more prescriptions throughout the acute treatment period. This last group was considered the “continuous-use” group.

The researchers constructed 30-month episodes for depression care, beginning with a six-month pretreatment period in which patients had no evidence of depression and received no mental health care. The second six months were considered the treatment period, during which time the initial diagnosis was made and medical therapy prescribed. This period included the six to eight weeks of acute treatment and at least an additional four months to allow for continued treatment, consistent with current guidelines. The final 18 months comprised the follow-up period, during which time continuation of medical treatment, adherence to therapy, relapse of depression, evidence of a suicide attempt, psychiatric hospitalization and use of electroconvulsive therapy were evaluated.

Approximately 93 percent of the 4,052 patients who were identified for this study were women; participants ranged in age from 18 to 83 years. Approximately one half of the patients were white and one half were black. All patients received a prescription for a TCA or an SSRI within 30 days of the initial diagnosis. Of these patients, 70 percent filled fewer than four prescriptions during the acute treatment period; 11 percent switched or augmented their prescriptions; and 19 percent met the criteria for the “continuous-use” group.

Overall, 23 percent of patients experienced a relapse during the follow-up period. Patients who had filled fewer than four prescriptions had the greatest rate of relapse, while those in the “continuous-use” group had the fewest number of relapses. Other risk factors for relapse included concurrent use of benzodiazepines and substance abuse.

The authors conclude that in most patients taking medication for major depression, the treatment is inadequate. Premature discontinuation of medication was associated with a 77 percent increase in the rate of relapse or recurrence of the depressive episode. Use of a single medication on a continuous basis results in the greatest reduction in the possibility for relapse.

editor's note: The results of this study are consistent with previously published data regarding the initial length of medical therapy for a depressive illness. The finding that 70 percent of patients do not complete treatment is disturbing. This high rate of noncompliance suggests that perhaps physicians should emphasize the importance of continued therapy and follow-up appointments to better monitor response and compliance.—j.t.k.