Dear Editor:

A number of empirical studies have previously linked disturbances in sleep with suicidal ideation and/or suicide attempts, but not with other forms of self-harm behavior. In this study, we examined relationships between poor sleep and various self-harm behaviors, hypothesizing that individuals with poor sleep would have higher rates of psychological disturbance and, therefore, demonstrate a greater number of different self-harm behaviors.

Participants were men and women, aged 18 years or older, who were being seen in an outpatient internal medicine clinic in a suburb of a mid-sized, mid-Western city. The sample was one of convenience. Exclusion criteria were medical (i.e., severe pain), intellectual, cognitive (e.g., dementia), or psychiatric (e.g., psychotic) impairment that would preclude the successful completion of a survey booklet.

During the study period (January 2009–September 2009), 149 patients were approached; 116 agreed to participate, for a response rate of 78 percent. Only 75 participants completed all study materials; 74.6 percent were women and 25.4 percent men, ranging in age from 18 to 70 years (M=41.6, standard deviation [SD]=13.8). Most participants were white (84%); however, six participants were African American, two Hispanic, and two Native American. All but 6.6 percent had at least graduated from high school whereas 26.6 percent had earned a college degree. One participant did not complete any demographic information.

During assigned clinic times, one of the investigators (Edwards) recruited participants from his clinical caseload as time allowed. Participants were asked to complete a six-page survey booklet; the cover page contained the elements of informed consent, and completion of the survey booklet was assumed to be implied consent. We initially explored demographic information and then assessed subjective sleep quality with the Pittsburgh Sleep Quality Index (PSQI).[1] The PSQI is a 19-item self-report questionnaire that explores subjective sleep quality over the past month. The last item relates to impressions of a bed partner and was deleted for this study, leaving a total of 18 items. The PSQI may be coalesced into one global score; a global PSQI score greater than five is considered to be a sensitive and specific measure of poor sleep quality. We explored self-harm behaviors with the self-harm inventory (SHI), a yes/no self-report measure that explores participants’ lifetime histories of 22 self-harm behaviors.[2] The SHI total score is the summation of “yes” responses. The Institutional Review Boards of both the affiliated community hospital and university approved this project.

Relationships between the SHI total score and individual SHI items, and the global PSQI score, are shown in Table 1.

There were no statistically significant differences in SHI total scores between poor sleepers and the remainder of the participants, which did not support our hypothesis. However, in correlational analyses, head banging (p<0.01) and suicide attempts (p<0.05) were statistically significantly associated with the global PSQI score, and in chi-square analyses, alcohol abuse (X2=3.970; p<0.05), distancing oneself from God as punishment (X2=4.966; p<0.05), and suicide attempts (X2=5.336; p<0.05) were statistically significantly associated with the global PSQI score (i.e., participants endorsing poor sleep quality evidenced a greater frequency of these specific self-harm behaviors). Thus, our findings indicate that among outpatients in a primary care clinic, poor sleepers do not have a significantly greater number of different self-harm behaviors than normal sleepers, but poor sleepers do have a significantly higher rate of specific self-harm behaviors (i.e., suicide attempts, head banging, alcohol abuse, and distancing oneself from God). This study has a number of potential limitations including the self-report nature of the data; small sample size; presence of incomplete data from a number of participants, who were excluded from analyses; and lack of assessment of potential psychiatric mediating variables (e.g., depression, anxiety, personality disorders). However, this is the first study to explore self-harm behaviors, beyond suicide attempts, in those with poor sleep quality. Only further research will clarify these potentially complex relationships. References
1. Buysse DJ, Reynolds CF III, Monk TH, et al. The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research. Psychiatry Res. 1989;28:193–213.
2. Sansone RA, Wiederman MW, Sansone LA. The self-harm inventory (SHI): development of a scale for identifying self-destructive behavior and borderline personality. J Clin Psychol. 1998;54:973–983.

With regards,
Randy A. Sansone, MD; Howard C. Edwards, MD; and Jeremy S. Forbis, PhD
Dr. Sansone is a Professor in the Departments of Psychiatry and Internal Medicine at Wright State University School of Medicine in Dayton, Ohio, and Director of Psychiatry Education at Kettering Medical Center in Kettering, Ohio. Dr. Edwards is a resident in the Department of Internal Medicine at Kettering Medical Center in Kettering, Ohio. Dr. Forbis is an Assistant Professor in the Department of Sociology at the University of Dayton in Dayton, Ohio.