Randomized study on the efficacy of cognitive-behavioral therapy for insomnia secondary to breast cancer, part II: Immunologic effects.
OBJECTIVE
Cross-sectional studies suggest that clinical insomnia is associated with immune downregulation. However, there is a definite need for experimental studies on this question. The goal of this randomized controlled study was to assess the effect of an 8-week cognitive-behavioral therapy (CBT) for chronic insomnia on immune functioning of breast cancer survivors. Previous analyses of this study showed that CBT was associated with improved sleep and quality of life, and reduced psychological distress.


METHODS
Fifty-seven women with chronic insomnia secondary to breast cancer were randomly assigned to CBT (n = 27) or to a waiting-list control condition (WLC; n = 30). Peripheral-blood samples were taken at baseline and post-treatment (and postwaiting for WLC patients), as well as at 3-, 6-, and 12-month follow-up for immune measures, including enumeration of blood cell counts (ie, WBCs, monocytes, lymphocytes, CD3+, CD4+, CD8+, and CD16+/CD56+) and cytokine production (ie, interleukin-1-beta [IL-1beta] and interferon gamma [IFN-gamma]).


RESULTS
Patients treated with CBT had higher secretion of IFN-gamma and lower increase of lymphocytes at post-treatment compared with control patients. Pooled data from both treated groups indicated significantly increased levels of IFN-gamma and IL-1beta from pre- to post-treatment. In addition, significant changes in WBCs, lymphocytes, and IFN-gamma were found at follow-up compared with post-treatment.


CONCLUSIONS
This study provides some support to the hypothesis of a causal relationship between clinical insomnia and immune functioning. Future studies are needed to investigate the clinical impact of such immune alterations.
Savard
Josée
J
Laval University Cancer Research Center, 11 Côte du Palais, Québec, Québec, Canada, G1R 2J6. josee.savard@psy.ulaval.ca
Simard
Sébastien
S
Ivers
Hans
H
Morin
Charles M
CM
D000368:Aged; D001772:Blood Cell Count; D001943:Breast Neoplasms / Q000150:complications* / Q000523:psychology; D002908:Chronic Disease; D015928:Cognitive Behavioral Therapy; D005260:Female; D006801:Humans; D007107:Immune System / Q000502:physiology*; D007371:Interferon-gamma / Q000097:blood; D007375:Interleukin-1 / Q000097:blood; D008214:Lymphocytes; D008875:Middle Aged; D007319:Sleep Initiation and Maintenance Disorders / Q000209:etiology / Q000276:immunology* / Q000628:therapy*; D016896:Treatment Outcome
D007375:Interleukin-1; D007371:Interferon-gamma