Study of delta sleep-inducing peptide efficacy in improving sleep on short-term administration to chronic insomniacs. — VialBase Research

Summary

This 1987 study assessed the effects of delta sleep-inducing peptide (DSIP) on the sleep cycle of insomniac patients using polysomnographic recordings. DSIP at a dose of 25 nmol/kg or placebo was administered intravenously over four nights in a double-blind crossover design. Several measures moved in the expected direction under DSIP — the number of nocturnal awakenings, non-rapid-eye-movement (NREM) sleep latency, total waking time, and waking time after sleep onset all decreased — but none of these reached statistical significance when compared to baseline or to double-blind placebo nights. Total sleep time and NREM sleep time were increased by the peptide, and that increase was attributable to increases in stage 2 sleep; stage 1, slow wave sleep (stages 3 and 4), and rapid-eye-movement sleep were not modified. The differences between DSIP and placebo for NREM sleep time and stage 2 sleep did reach significance, but the authors flagged the critical confound: the same differences already existed in the baseline values, so they cannot be cleanly attributed to the drug. The authors’ own conclusion was that sleep improvement under DSIP treatment is of little clinical significance. The abstract does not report the number of patients enrolled.

Key Findings

• Double-blind crossover design in chronic insomniacs: DSIP 25 nmol/kg versus placebo, administered intravenously across four nights, with objective polysomnographic recording
• Nocturnal awakenings, NREM sleep latency, total waking time, and waking time after sleep onset decreased under DSIP — but no significant differences versus baseline or versus double-blind placebo nights
• Total sleep time and NREM sleep time increased under DSIP, driven entirely by increases in stage 2 (light) sleep
• Stage 1, slow wave sleep (stages 3 and 4), and REM sleep were not modified — the peptide named for delta-sleep induction did not increase delta sleep in these patients
• The significant DSIP-versus-placebo differences in NREM and stage 2 sleep were already present at baseline, so the authors concluded that sleep improvement under DSIP is of little clinical significance

Relevance to DSIP

For anyone evaluating DSIP as a sleep aid, this trial is close to the whole of the controlled human evidence base, and it does not support the marketing. It is a small, short, four-night intravenous crossover study from 1987 whose abstract does not even report a sample size, and its authors’ plain-language conclusion is that any sleep improvement was of little clinical significance. Two details deserve particular weight. First, the one apparently significant result — more NREM and stage 2 sleep on DSIP than placebo — was contaminated by a pre-existing baseline difference between conditions, which is exactly the pattern that produces false positives in small crossover designs. Second, the peptide failed to increase slow wave sleep, the stage its own name advertises; the extra sleep it produced was stage 2, the lightest consolidated stage. Compounding all of this, the study used intravenous dosing under laboratory conditions, which is not how DSIP is administered by people buying it today, and nothing of comparable rigor has replicated or extended it in the decades since. Cite this as a negative-to-null human result, not as clinical validation.

Citation

Monti JM, Debellis J, Alterwain P, et al. Study of delta sleep-inducing peptide efficacy in improving sleep on short-term administration to chronic insomniacs. International journal of clinical pharmacology research. 1987;7(2):105-10.

See Also

• Parent compound: DSIP