A “Two-Hit” Model for Depression Vulnerability in Women

Both sleep disturbance and inflammatory conditions have been linked to depression susceptibility. To study the potential interactions between these two factors, researchers enrolled 111 healthy university students (67 women) who were assessed for self-reported sleep quality during the prior month and for current depressed mood. Participants were randomized to injections of placebo or Escherichia coli endotoxin at doses sufficient to raise levels of interleukin (IL)-6 tenfold and tumor necrosis factor α (TNF-α) fivefold (comparable to increases seen in HIV infection and rheumatoid arthritis); inflammatory cytokine levels and mood ratings were evaluated hourly for 6 hours.

Baseline scores on a depressive-symptoms inventory were modestly higher…