Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion.
Specific interventions included in the review
Studies of IPT, a time-limited weekly out-patient psychotherapy, were eligible for inclusion. The included studies compared IPT (with or without medication) with medication, placebo, cognitive-behaviour therapy (CBT), clinical monitoring, usual care or remaining on a waiting list. The study duration ranged from 12 to 96 weeks (up to 150 weeks for two studies of maintenance IPT).
Participants included in the review
Studies of patients with DSD, diagnosed by standardised criteria, were eligible for inclusion. Studies of patients with bipolar disorder were excluded. The participants in the included studies had diagnoses of dysthymia (with or without major depression), major depression, mood disorder or neurotic depression.
Outcomes assessed in the review
It was unclear whether inclusion criteria for the outcomes were specified in advance. The included studies evaluated treatment efficacy on a wide range of scales, most of which assessed depressive symptoms, quality of life or general health. The authors grouped outcomes into those dealing with:
remission of symptoms (defined as no symptoms or a score of less than 8 points on 17-point Hamilton depression rating scale);
clinical improvement of symptoms (defined as a 50% or greater improvement in depressive symptoms);
a difference in mean depressive symptoms at the end of the study; and
recurrence of depressive symptoms.
The proportion of patients from each treatment group who dropped out of the study was also assessed. In the review, the outcomes were assessed during the acute phase of treatment (less than 24 weeks), during the maintenance phase (more than 24 weeks) and during the prophylaxis phase.
How were decisions on the relevance of primary studies made?
Two reviewers independently assessed studies for relevance; any disagreements were resolved by consensus.