Depression has been associated with both insomnia – lack of sleep – and hypersomnia – excessive sleepiness. Researchers in UT Southwestern’s Center for Depression Research and Clinical Care have identified two biological markers for hypersomnia. Exercise decreased the levels of the two biomarker proteins, resulting in a reduction in excessive sleepiness, the researchers found.

“Hypersomnia, as well as insomnia, has been linked in the development, treatment, and recurrence of depression. Sleep disturbances are also some of the most persistent symptoms in depression. Identifying these biomarkers, combined with new understanding of the important role of exercise in improving several aspects of depression including cognition, self-efficacy, energy, and motivation, together with reducing hypersomnia, has major implication for the treatment of depression,” said Dr. Madhukar Trivedi, Director of the Center, Chief of the Mood Disorders Division of Psychiatry, and holder of the Betty Jo Hay Distinguished Chair in Mental Health, and the Julie K. Hersh Chair for Depression Research and Clinical Care.

The biomarkers were identified based on blood samples from participants in the Treatment with Exercise Augmentation for Depression (TREAD) study, which examined the effects of exercise on depression. Four biomarkers were examined − brain-derived neurotrophic factor (BDNF), tumor necrosis factor alpha (TNF-α), IL-1β, and IL-6. Levels of these biomarkers were measured from blood samples collected before and after the 12-week exercise intervention.

Dr. Madhukar Trivedi (right) confers with one of the patients who took part in a recent study that identified biomarkers for hypersomnia, a condition associated with excessive daytime sleepiness.

Reductions in two biomarkers, BDNF and IL-1β, were found related to reductions in hypersomnia. Interestingly, these biomarkers were unique to hypersomnia and were not associated with changes in insomnia. Researchers did find that people with lower baseline levels of IL-1β had greater improvement in insomnia.

The findings, reported in Translational Psychiatry in late 2015, suggest distinct mechanisms are involved in insomnia versus hypersomnia, and that further research will be needed to identify the appropriate treatments to match these sleep-disturbance biomarkers.

UT Southwestern’s Center for Depression Research and Clinical Care was established with a $5 million gift from the Hersh Foundation to accelerate new discoveries into the causes and treatment of depression and mood disorders.