Can sleep disturbance in depression predict repetitive transcranial magnetic stimulation (rTMS) treatment response?
Treatment for depression is not effective in all patients and it is therefore important to identify factors that can be used to tailor treatments. One potential factor is insomnia. Several repetitive transcranial magnetic stimulation (rTMS) studies have reported on this symptom, however, they did not take into account the presence of hypersomnia or that insomnia was related to their outcome measure. Our aim was to investigate whether baseline sleep disruption was related to rTMS treatment response. We pooled data from four clinical trials using rTMS to treat depression, including 139 subjects in data analysis. Insomnia was measured using the Hamilton Depression Rating Scale (HamD) sleep questions and hypersomnia from the Beck Depression Inventory (BDI). To reduce the possible impact of insomnia on our treatment response outcome we created an adjusted HamD score which omitted sleep items. Sleep disturbances were common in our study: 66% had insomnia and 38% hypersomnia. Using regression analysis with our adjusted HamD score we found no relation between baseline insomnia or hypersomnia and rTMS treatment response. Our data are consistent with previous studies; however, this is the first rTMS study to our knowledge that has attempted to dissociate baseline insomnia from the HamD outcome measure and to report no relationship between hypersomnia and rTMS outcome.