Major depressive disorder (MDD) is a common disorder, widely distributed throughout the population, and usually associated with substantial symptoms and role impairment. The prevalence of cases of lifetime MDD was 16.2% in the United States and 12.8% in Europe [1, 2]. The mean duration of a depressive episode was 16 weeks and 59.3% of patients with MDD lasting just one year had severe or very severe role impairment . Moreover, MDD is a long-lasting illness with significant effects on the patient’s family, social life, and work life [3, 4]. Treatment failure results in a low recovery rate and frequent relapses . According to studies on the naturalistic course of MDD, a prospective study in Japan showed that 10 to 20% of patients entering treatment remain chronically depressed without recovery for one or even two years . Once recovered, the cumulative probability of remaining well without subthreshold symptoms was 57% at one year, 47% at two years, and 35% at five years .
MDD can also cause severe suffering for family members of the patient in multiple areas including a higher level of divorce  and severe financial strain . Fadden et al.  reported that the burden on the relatives of patients with MDD included restrictions in social and leisure activities, a fall in family income, and a considerable strain on the marital relationship. Relatives of patients with depression found some of the behaviors of the patients to be difficult to bear, and the relatives had negative consequences such as grief, withdrawal, and worrying, which commonly caused problems. However, few relatives know how to deal with the difficult behavior of patients . Moreover, sleep disturbance, odd ideas and/or behavior, and appetite loss in MDD patients were not seen by any relatives as being under the patient’s control, whereas nagging, grumbling, obsessionality, and worrying were seen by a varying proportion of relatives as personality attributes . Therefore, the relatives felt dissatisfaction in that the patient could control those behaviors . Jacob et al.  reported disruptions in the lives of close family members because of their own worrying and also because of the patient’s lack of interest in things and feelings of worthlessness. Taken together, these findings suggest that living with a patient with MDD is a source of strain and emotional distress for relatives.
Among relatives of patients with MDD, the patient’s behavior and mood disturbance and relative’s emotional distress were associated with the relatives’ mental health [12–14]. The difficultness of maintaining functioning family relationships (for example the patient may have marital problems, poorer communication, and no problem-solving skills) was associated with poorer long-term outcome for the depression [15, 16]. Rounsaville et al.  reported that a reduction in the number of marital disputes was associated with improved depressive symptoms and social functioning after eight months of individual psychotherapy in depressed female outpatients. Several studies reported that the quality of family functioning was associated with the relapse rate. The family’s expressed emotion (EE) is a good predictor of whether a patient relapses; Hooley et al.  reported that 59% of patients whose spouses had high levels of EE relapsed, although no patients living with low-EE spouses did so over a nine-month follow-up period. Although Hayhurst et al.  reported that there was no clear association between the EE of a spouse and the recurrence of depression in the patient, five studies reported that a high EE predicted a high relapse rate [18, 20–23].
These studies suggest the need for a more family-oriented approach in the treatment of MDD. However, a review conducted by Henken et al.  reported that family therapy such as behavioral intervention including psychoeducation, psychodynamic intervention, and systemic intervention for the families of patients with depression, seems to be more effective than no treatment or being placed on a waiting list. However it remains unclear how effective this intervention is in comparison with other interventions such as group intervention, individual cognitive intervention, and behavioral intervention. In spite of the lack of high-quality evidence in this field, family therapy is already a widely-used intervention for the treatment of depression .
Family psychoeducation is recognized as part of the optimal treatment for patients with a psychotic disorder [25, 26]. This intervention has been shown to reduce the rates of relapse and hospitalization among individuals with psychotic disorders and is recognized as an evidenced-based treatment for psychotic disorders . Two randomized controlled trials have found that family psychoeducation is effective in enhancing the course of MDD [28, 29]. In a study of adolescents with MDD, patients in the group who received family psychoeducation showed greater improvements in social functioning and adolescent-parent relationship than the control group . Among patients with MDD in partial or full remission, patients who were treated with the family psychoeducation had a significantly lower relapse rate than patients who were in the control group . However, neither of these two trials assessed relatives’ mental health as the primary outcome. Additionally, although MDD can easily become chronic, there has been no intervention study for the families of patients with MDD lasting more than one year.
In the present study, we perform a randomized controlled trial to examine the effectiveness of family psychoeducation in improving the mental health of the relatives of patients with MDD lasting more than one year. The hypothesis is that, compared with relatives who receive one regular counseling session from a nurse, relatives receiving family psychoeducation will show a greater improvement in mental health as measured by K6 scale at 16 weeks post-randomization.