Why is this review important?
Depression is a common mental disorder characterised by sadness, loss of pleasure in most activities, feelings of worthlessness or guilt, thoughts of death or suicide. Couple therapy has been suggested as a treatment for couples with a depressed partner on the basis of the association between depressive symptoms and relationship distress, the role of relational negative factors in onset and maintenance of depression, and the buffering effect of intimacy and interpersonal support. Couple therapy works by modifying negative interactional patterns and increasing mutually supportive aspects of relationships. It is important to know whether couple therapy can help people with depression.
Who will be interested in this review?
This review will be of interest to people with depression, their partners, and people involved in their care.
What questions does this review aim to answer?
This review aimed to assess evidence about the effects of couple therapy for couples with a depressed partner.
Which studies were included in the review?
We considered studies of couple therapy delivered in outpatient settings to couples in which a partner had a clinical diagnosis of depressive disorder. We included 14 studies with 651 participants .Thirteen of the studies were randomised controlled trials, where participants were assigned by chance alone to the couple therapy treatment group or usual care. However, one study was not completely randomised due to therapist availability.
What does the evidence from the review tell us?
There was low-quality evidence to suggest that couple therapy is as effective as individual psychotherapy in improving depression. People with depression might do better when receiving couple therapy compared with no treatment, but we are very uncertain about this effect because of the very low quality of studies. In comparison with treatment with antidepressant medication, limited data was available. Although data on few dropouts favour couple therapy, the very low quality of data seriously weakens this finding. The comparison between couple therapy plus antidpressant medication and antidepressants alone showed no difference in depressive symptom level, but the results were based on two small studies. Couple therapy was more effective in reducing relationship distress than individual psychotherapy and this effect was enhanced when distressed couples were considered separately. However, this result has to be considered with great caution, because of the very low quality of studies. Most studies were affected by small sample sizes, unclear sample representativeness, loss of participants at follow-up, and investigators' allegiance bias. Moreover, there were few follow-ups that went beyond 6 months post-treatment. Only one study tested whether improvements in couple relationships led to improvement in depression, finding supporting evidence for that. However, the small sample of this study and the lack of other studies which investigated this hypothesis means we could not test in this review if this finding was supported. Although it is difficult to draw conclusions with any confidence on differences between couple therapy and other treatments for depression, the possibility of improvement in couple relationships may favour its choice when relationship distress is a major problem.
What should happen next?
We need good quality trials, testing in large samples with long follow-up of the effects of couple therapy in comparison to other interventions, especially in distressed couples.
Although there is suggestion that couple therapy is as effective as individual psychotherapy in improving depressive symptoms and more effective in improving relations in distressed couples, the low or very low quality of the evidence seriously limits the possibility of drawing firm conclusions. Very few data were available for comparisons with no/minimal treatment and drug therapy. Future trials of high quality should test in large samples with a long follow-up of the effects of couple therapy in comparison to other interventions in discordant couples with a depressed partner, considering the role of relationship quality as a potential effect mediator in the improvement of depression.
Couple therapy for depression has the twofold aim of modifying negative interaction patterns and increasing mutually supportive aspects of intimate relationships, changing the interpersonal context of depression. Couple therapy is included in several guidelines among the suggested treatments for depression.
1. The main objective was to examine the effects of couple therapy compared to individual psychotherapy for depression.
2. Secondary objectives were to examine the effects of couple therapy compared to drug therapy and no/minimal treatment for depression.
The Cochrane Common Mental Disorders Group Controlled Trials Register (CCMDCTR), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid), Embase (Ovid) and PsycINFO (Ovid) were searched to 19 February 2018. Relevant journals and reference lists were checked.
Randomised and quasi-randomised controlled trials examining the effects of couple therapy versus individual psychotherapy, drug therapy, or no treatment/minimal treatment for depression were included in the review.
We considered as primary outcomes the depressive symptom level, the depression persistence, and the dropouts; the relationship distress level was a secondary outcome. We extracted data using a standardised spreadsheet. Where data were not included in published papers, we tried to obtain the data from the authors. We synthesised data using Review Manager software version 5.3. We pooled dichotomous data using the relative risk (RR), and continuous data calculating the standardised mean difference (SMD), together with 95% confidence intervals (CIs). We employed the random-effects model for all comparisons and also calculated a formal test for heterogeneity, the natural approximate Chi2 test.
We included fourteen studies from Europe, North America, and Israel, with 651 participants. Eighty per cent of participants were Caucasian. Therefore, the findings cannot be considered as applicable to non-Western countries or to other ethnic groups in Western countries. On average, participants had moderate depression, preventing the extension of results to severely depressed patients. Almost all participants were aged between 36 and 47 years.
There was no evidence of difference in effect at the end of treatment between couple therapy and individual psychotherapy, either for the continuous outcome of depressive symptoms, based on nine studies with 304 participants (SMD −0.17, 95% CI −0.44 to 0.10, low-quality evidence), or the proportion of participants remaining depressed, based on six studies with 237 participants (RR 0.94, 95% CI 0.72 to 1.22, low-quality evidence). Findings from studies with 6-month or longer follow-up confirmed the lack of difference between the two conditions.
No trial gave information on harmful effects. However, we considered rates of treatment discontinuation for any reason as a proxy indicator of adverse outcomes. There was no evidence of difference for dropout rates between couple therapy and individual psychotherapy, based on eight studies with 316 participants (RR 0.85, 95% CI 0.51 to 1.41, low-quality evidence).
Few data were available for the comparison with drug therapy. Data from a small study with 12 participants showed no difference for the continuous outcome of depressive symptoms at end of treatment (SMD −0.51, 95% CI −1.69 to 0.66, very low-quality evidence) and at 6-month follow-up (SMD −1.07, 95% CI -2.45 to 0.31, very low-quality evidence). Data on dropouts from two studies with 95 participants showed a clear advantage for couple therapy (RR 0.31, 95% CI 0.15 to 0.61, very low-quality evidence). However, this finding was heavily influenced by a single study, probably affected by a selection bias favouring couple therapy.
The comparison between couple therapy plus drug therapy and drug therapy alone showed no difference in depressive symptom level, based on two studies with 34 participants (SMD −1.04, 95% CI -3.97 to 1.89, very low-quality evidence) and on dropouts, based on two studies with 45 participants (RR 1.03, 95% CI 0.07 to 15.52, very low-quality evidence).
The comparison with no/minimal treatment showed a large significant effect favouring couple therapy both for depressive symptom level, based on three studies with 90 participants: (SMD −0.95, 95% CI −1.59 to −0.32, very low-quality evidence) and persistence of depression, based on two studies with 65 participants (RR 0.48, 95% CI 0.32 to 0.70, very low-quality evidence). No data were available for dropouts for this comparison.
Concerning relationship distress, the comparison with individual psychotherapy showed that couple therapy appeared more effective in reducing distress level at the end of treatment, based on six studies with 187 participants (SMD −0.50, CI −0.97 to −0.02, very low-quality evidence) and the persistence of distress, based on two studies with 81 participants (RR 0.71, 95% CI 0.51 to 0.98, very low-quality evidence). The quality of evidence was heavily affected by substantial heterogeneity (I2 = 59%). In the analysis restricted to studies including only distressed couples, no heterogeneity was found and the effect in distress level at the end of treatment was larger (SMD −1.10, 95% CI −1.59 to −0.61). Very few data on this outcome were available for other comparisons.
We assessed the certainty of the evidence using the GRADE system. The results were weakened by the low quality of evidence related to the effects on depressive symptoms, in comparison with individual psychotherapy, and by very low quality evidence for all other comparisons and for the effects on relationship distress. Most studies were affected by problems such as the small number of cases, performance bias, assessment bias due to the non-blinding outcome assessment, incomplete outcome reporting and the allegiance bias of investigators. Heterogeneity was, in particular, a problem for data about relationship distress.