Sleep disturbance mediates the association between psychological distress and immune status among HIV-positive men and women on combination antiretroviral therapy.

OBJECTIVES This study examined the relationship between psychological distress, subjective sleep disturbance and immune status among HIV-positive men and women. METHODS Fifty-seven participants (41 men, 16 women) without AIDS-related illness and currently on combination antiretroviral therapy were recruited through community advertisement and physician referral. Participants completed the Impact of Events Scale (IES) to assess symptoms of psychological distress and the Pittsburgh Sleep Quality Index (PSQI) to assess quality of sleep over the past month. T-lymphocyte subpopulations were also assessed from early morning blood samples. RESULTS Participants reporting greater psychological distress also reported more pronounced sleep disruption. Higher levels of distress and greater sleep disturbance were also significantly related to lower T-cytotoxic/suppressor (CD3+CD8+) cell counts. Path analysis revealed that the association between distress level and CD3+CD8+ cell counts was mediated by poorer subjective sleep quality. CONCLUSIONS These findings suggest that psychological distress may impact upon the immune system through its effects on sleep quality.