An unsuccessful attempt to develop a single-item screen for insomnia in cancer patients

The focus of this pilot study was to examine issues of criterion validity and detection of insomnia utilizing a single item from the Zung Self-Rating Depression Scale (ZSDS) as a means to rapidly screen cancer patients in ambulatory oncology clinics. In our previous work, we have demonstrated the usefulness of other single items for screening purposes, such as for fatigue. The sleep item reads "I have trouble sleeping through the night" and is rated on a 4-point Likert scale ranging from "none or little of the time" to "most or all of the time." Fifty-two oncology patients were administered the ZSDS and further evaluated with the Pittsburgh Sleep Quality Index (PSQI). The sensitivity and specificity of various cutoffs on the ZSDS sleep item were investigated as predictors of the PSQI. Results revealed that the ZSDS single-item screen has poor sensitivity and specificity for detecting insomnia in cancer patients, and that the relationship between insomnia and depression is more complicated than anticipated. The use of this single item, or perhaps any single item, as a means of screening for sleep disturbances in cancer patients may be problematic. A better understanding of insomnia and its measurement are worthwhile areas of study.