Predictors of response to combined wake and light therapy in treatment-resistant inpatients with depression

ABSTRACT

There is growing evidence for combined chronotherapeutic interventions as adjunctive treatments for major depression. However, as the treatments can be demanding, we need to identify predictors of response. This study aimed to describe predictors of response, remission and deterioration in the short-term phase, as well as predictors of long-term response. The predictors investigated were gender, type of depression, severity of depression, treatment resistance, quetiapine use, general self-efficacy, educational level and positive diurnal variation. Follow-up data from 27 inpatients with moderate-to-severe depression participating in a chronotherapeutic intervention were analysed. As a supplement to standard treatment, they completed 3 wake therapy sessions in the first week, 30 min daily light treatment and sleep-time stabilisation in the entire 9-week study period. Patients had a significant decrease of depressive symptoms during the first 6 days measured by HAM-D6. At Day 6, 41% of the patients responded to the treatment and 19% fulfilled the criteria of remission. Deterioration by the end of wake therapy sessions was however not uncommon. In the short-term phase, mild degree of treatment resistance was associated with remission and low educational level associated with deterioration. Positive diurnal variation (mood best in the evening) was a predictor of both short-term and long-term response to combined wake and light therapy. Furthermore, patients with evening chronotypes (measured with morningness-eveningness score) were more responsive. Our results suggest that targeting the combined chronotherapeutic intervention at patients with positive diurnal variation and evening types is a viable option.

KEYWORDS:

• Chronotherapy
• sleep deprivation
• depressive disorder
• light therapy
• diurnal variation
• sleep

Acknowledgements

The authors wish to acknowledge Ann-Sofie Knuth, Shanthi Kondrup, Anne Bastholm Blicher and Christine Warberg for their contributions of recruiting patients, assessments and data entry. Furthermore, we wish to acknowledge Nikolaj Juul Madsen for statistical support.

Declaration of interest

The authors do not have any conflicts of interest to report.

Additional information

Funding

This study was supported by grants from the Aase and Ejnar Danielsens Foundation, the Novo Nordisk Foundation, the Foundation for Research in Psychiatry, the Foundation for Advancement of Psychiatry, and Health Research Fund of Central Denmark Region.