Mechanisms of Cognitive Behavioral Therapy and Light Therapy for Cancer-Related Insomnia: A Randomized Clinical Trial during Chemotherapy for Breast Cancer

ABSTRACT

Study Objectives

This study aimed to investigate the mechanisms of a combined brief cognitive behavioral plus bright light therapy (CBT-I+Light) in women receiving chemotherapy.

Methods

Women (N = 101) were randomly assigned to CBT-I+Light or treatment as usual plus relaxation audios (TAU+). Participants completed sleep diaries and wore an actigraph during the 6-week intervention period. Patient-reported outcomes were assessed at baseline, mid-point (week 3), and later (week 6). Cognitive (i.e., dysfunctional sleep beliefs, pre-sleep cognitions, and arousal) and behavioral (i.e., time in bed awake and day-to-day out-of-bedtime variability) mechanisms were examined.

Results

Cognitively, both groups declined significantly in overall dysfunctional sleep beliefs from pre- to post-intervention (both p< .04); however, they did not differ on sleep-related beliefs nor pre-sleep cognitions and arousal at post-intervention (both p> .50). Dysfunctional beliefs sleep expectations subscale was lower in CBT-I+Light versus TAU+ (p= .01). Behaviorally, CBT-I+Light reported less overall time in bed awake after the start of the intervention (p< .05) and significantly less time in bed during the morning until the final week of the intervention period. Out-of-bedtime day-to-day variability was lower in the CBT-+Light vs TAU+ at the final intervention day.

Conclusion

Mechanisms of CBT-I+Light during chemotherapy remain to be shown. Our results suggest that changes in behavioral mechanisms may be associated with sleep improvements within this cohort. Future studies should assess the role of additional mechanisms (e.g., sleep effort) within larger samples. Whilst intervention brevity is important, more potent interventions may be required to achieve robust changes in target mechanisms.

Abbreviations

CBT-I: Cognitive behavioral therapy for insomnia; CBT-I+Light: Combined brief cognitive behavioral plus bright light therapy; DBAS: Dysfunctional Beliefs and Attitudes about Sleep Scale; ISI: Insomnia Severity Index; PSA: Pre-Sleep Arousal Scale; TAU+: Relaxation enhanced treatment as usual; TIBA: Time in bed awake

Acknowledgments

The authors thank the study participants and the medical staff at the Peter MacCallum Cancer Centre.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contribution

JM: data collection, current study design, and conceptualization; data cleaning and analysis; wrote the manuscript.

HRB: trial conceptualization, data collection, and manuscript review and editing.

JD: trial conceptualization and manuscript review and editing.

MF: trial conceptualization and manuscript review and editing.

MA: trial conceptualization and manuscript review and editing.

QL: manuscript review and editing.

LS: trial conceptualization and manuscript review and editing.

BB: trial conceptualization and manuscript review and editing.

PAF: trial conceptualization and manuscript review and editing.

JFW: trial conceptualization, formal analysis, funding acquisition, writing original draft, and writing reviewing and editing.

Clinical trial information

Registered with the Australian New Zealand Clinical Trials Registry (http://anzctr.org.au/), Registration Number: ACTRN12618001255279

Additional information

Funding

This study was supported by seed funding from Monash University with light glasses provided by Lucimed SA, Belgium. Wiley (1178487) and Bei (1140299) were supported by NHMRC fellowships. The funders had no role in the study design, data collection, analysis, interpretation, or presentation of results.