To assess the effectiveness of a 12-week multidomain intervention with contingency management for reducing depressive symptoms in older adults with major depressive disorder.

Awareness of the necessity and importance of community-based multidomain psychosocial intervention for late-life depression has increased. However, few studies have attempted to integrate several therapeutic approaches in one intervention program.

Main objective of this study is to assess the effectiveness of a 12-week multidomain intervention with contingency management for reducing depressive symptoms in older adults with major depressive disorder.

We plan to conduct a randomized controlled parallel-design study. We plan to allocate study participants to multidomain intervention or supportive therapy group, in a 1:1 ratio. Block randomization using SAS (PLAN procedure) and sample size estimation were performed. We estimated that, with at least 40 participants per group and an attrition rate of 10%, we could achieve a power of at least 0.80 (beta = 0.2, two-tailed alpha = 0.05).

Intervention was based on the financial and human resources of a community mental health service, and involved four home visits and 12 telephone calls over 12 weeks. Four evidence-based therapeutic approaches (physical activity, healthy diet, social activity, and emotional regulation) were incorporated into the multidomain intervention program. To maintain participant motivation, we plan to apply contingency management based on operant conditioning theory.

The primary outcome is the change in depressive symptoms, as measured by the Montgomery-Asberg Depression Rating Scale (MADRS). Secondarily, we plan to investigate changes in resting-state functional connectivity in the default mode, salience, and central executive networks.

Inclusion Criteria:

1. a diagnosis of non-psychotic, unipolar major depressive disorder, based on the Mini-International Neuropsychiatric Interview
2. a Montgomery-Asberg Depression Rating Scale (MADRS) score of 17 or higher
3. the use of antidepressants at stable dosage for at least 6 weeks prior to study entry, without any recommendation for changes in medication for the 12 weeks of the intervention. Pharmacotherapy was uncontrolled and was provided by physicians.

Exclusion Criteria:

1. a history of psychiatric disorder (mental retardation, schizophrenia, bipolar disorder, and dementia)
2. a history of neurological disorder, such as brain tumor, intracranial hemorrhage, subarachnoid hemorrhage, epilepsy, hydrocephalus, encephalitis, metabolic encephalopathy, or other neurologic conditions that could interfere with the study
3. a history of significant hearing or visual impairment
4. a history of physical illnesses that could interfere with the study.

Due to the nature of the intervention, we were unable to blind the nurses performing the intervention. However, to achieve double blinding as rigorously as possible, group allocation was not divulged to participants, and symptoms were rated by independent psychologists unaware of the randomization status.