The relationship between the HDRS insomnia items and polysomnographic (PSG) measures in individuals with treatment-resistant depression.

The Hamilton Depression Rating Scale (HDRS), which includes several insomnia-related items, is potentially valuable in evaluating both depressive and sleep symptoms. However, the HDRS insomnia items have not been fully assessed by objective measures. This study compared the three HDRS insomnia items (Early, Middle, and Late) with the corresponding objective polysomnography (PSG) measures of Sleep Latency (SL), middle wakefulness, and late wakefulness. The study used HDRS and PSG data from 130 baseline nights, drawn from 80 participants enrolled in clinical trials for treatment-resistant depression (TRD). Mixed models evaluated the relationship between the HDRS and PSG, and primary analyses examined the Early, Middle, and Late Insomnia HDRS items and the PSG variables SL and Waking After Sleep Onset (WASO). To approximate the Middle and Late HDRS Insomnia items more closely, WASO was divided into WASO before 4:00 a.m. (waking between Sleep Onset and 0400 h) and WASO after 4:00 a.m. (waking between 0400 h and 0700 h). Secondary analyses included summed HDRS Global Insomnia score. HDRS Early and Late Insomnia items predicted objective PSG measures of early and late wakefulness. For Early Insomnia, each additional point in severity was associated with 61% [95%CI: 35%, 93%] longer SL. For Late Insomnia, each additional point was associated with a 35% [95% CI: 13%, 63%] increase in WASO after 4:00 a.m. Middle Insomnia was marginally related to WASO before 4:00 a.m. HDRS Early and Late Insomnia items may thus provide an index of wakefulness in TRD and help monitor treatment response when objective measures such as PSG are not feasible. CLINICAL TRIALS IDENTIFIER: www.clinicaltrials.gov (NCT01204918, NCT00054704, NCT00088699).