Continuation treatment typically lasts 4-9 months. The length of the continuation period, in theory, depends on the length of the prior episode. Continuation treatment aims at preventing the return of the most recent episode until its natural course, as determined by its physiology and biology, would have ended spontaneously. Thus, patients with longer prior episodes (e.g., 15 months) whose current episode of depression has lasted for 2 months, for example, would be candidates for 11 months of continuation-phase treatment, assuming that successful acute-phase treatment required 2 months. For patients with psychotic depression, follow-up studies 1 year after acute-phase treatment indicate a poorer prognosis than for patients with nonpsychotic depression. Thus, continuation-phase treatment for psychotic depression should last longer.

Continuation-phase medication treatment should usually end with a gradual medication taper—especially for those taking serotonin active agents with shorter half-lives (Rosenbaum et al. 1998).

Whether medication is used alone or combined with psychotherapy in the acute phase, continuation-phase medication is recommended, because early discontinuation of medication is associated with a higher relapse rate compared with later medication discontinuation (Depression Guideline Panel 1993). Continuation-phase medication is recommended at the same dosage used during the acute phase.

Strategies and Tactics in the Treatment of Depression Introduction Acute-Phase Treatment -General Issues -Strategic Issues -Tactical Issues -Treatment With Medication and Formal Psychotherapy Continuation-Phase Treatment Maintenance-Phase Treatment Patient Preference Conclusions Antidepressant and Antimanic Medications Depression-Focused Psychotherapies Psychodynamic Psychotherapies Combined Medication and Psychotherapy Electroconvulsive Therapy Light Therapy Treatment-Resistant Mood Disorders Treatment of Mood Disorders in the Medically Ill Patient

Psychotherapy may be added to continuation medication if psychosocial or depressive symptom residua are present and are not ameliorated by medication alone (Fava et al. 1998a, 1998b; Paykel et al. 1999). Whether psychotherapy should be continued after response to acute-phase combined treatment is unknown. Whether continuation-phase psychotherapy is recommended after successful response to acute-phase psychotherapy is also unclear. However, Jarrett et al. (1998) found that acute-phase cognitive therapy responders who received continuation-phase cognitive therapy treatment after their acute-phase treatment had fewer relapses and recurrences compared with those who had received only acute-phase cognitive therapy. Similarly, Blackburn et al. (1986) reported a lower relapse rate among patients who received both acute- and continuation-phase cognitive therapy, which is in contrast to reports in the literature of higher relapse rates for acute-phase cognitive therapy responders who were not provided continuation-phase treatment.