Insomnia does not predict depression treatment outcomes
medwireNews: Hypersomnia and insomnia do not influence repetitive transcranial magnetic stimulation (rTMS) treatment outcomes in patients with depression, researchers confirm.
To reduce the possible impact of changes in insomnia symptoms as a result of treatment on depression treatment response, they used an adjusted Hamilton Depression (HamD) Scale score that omitted questions 4 to 6, which relate to insomnia symptoms.
"We felt this necessary as we were investigating the impact of baseline sleep disturbance; changes in these patients would affect their depression score and potentially the frequency of treatment response," point out Paul Fitzgerald (The Alfred and Monash University Central Clinical School, Victoria, Australia) and colleagues.
Despite this, sleep disturbance was still related to rTMS treatment in that patients were more than twice as likely to be free of insomnia following treatment, and patients who responded to rTMS were nearly eight times more likely to be free of insomnia than nonresponders.
"This is likely to result from the close relationship between the symptom of insomnia and depression," says the team in Psychiatry Research.
A total of 139 patients with depression participated in the study, and their mean HamD and adjusted HamD scores before treatment were 23.7 and 20.5, respectively.
Insomnia, defined as scoring a total of 2 on at least one of the three HamD insomnia questions for early, middle, and late insomnia, was diagnosed in 66% of patients, while hypersomnia (scoring 2a or 3a on question 16 of the Beck Depression Inventory) was evident in 38%.
Participants with insomnia had significantly higher HamD scores at baseline, at 24.8 versus 21.7 for those without the condition. But patients with insomnia were no less likely to respond to rTMS treatment than those without insomnia.
"To our knowledge this is the first study investigating this that has attempted to dissociate insomnia symptoms from the outcome measure and has included the potential confounder of hypersomia," say Fitzgerald et al.
"Further research is needed to investigate whether any other sleep measures are important in predicting rTMS response, for example [electroencephalogram] measures such as [rapid eye movement] density."
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By Lucy Piper, Senior medwireNews Reporter