Naps after total sleep deprivation in depressed patients: are they depressiogenic?

Total sleep deprivation (TSD) exerts beneficial but transient effects on mood in approximately 60% of patients with a major depressive disorder. The positive effects of a night of total sleep deprivation are generally reversed after the next night of sleep. Several anecdotal reports and a pilot study by our group indicated that even short naps during the period of sleep deprivation are capable of re-inducing depressive mood in responders to TSD. The present study explored whether the structure of naps at 9 a.m. was crucial for the "depressiogenic" impact of naps on mood. A negative effect on mood was replicated, but this effect was not related to any of the nap sleep variables. The effect of naps on mood was attenuated in the early afternoon. The results support the assumption of a "depressiogenic" effect of naps in patients with major depression after successful TSD.