Posted by Phillipa on August 1, 2013, at 21:09:44
Medscape Medical News > PsychiatryAnesthetic a Better Alternative to ECT in Resistant Depression?
Megan Brooks
Jul 31, 2013
Deep-inhalation isoflurane anesthesia has an antidepressant effect that approaches the effect of electroconvulsive therapy (ECT), with fewer cognitive side effects, preliminary results indicate.If confirmed, isoflurane could be "another potential tool in our toolbox for treating severe refractory depression," principal investigator Howard R. Weeks, MD, University of Utah School of Medicine in Salt Lake City, told Medscape Medical News.
The study was published online July 26 in PLoS One.
Plagued by Stigma
Although ECT remains the most effective treatment for severe refractory depression, "it continues to have stigma that discourages many patients from considering it," said Dr. Weeks.
"Side effects of ECT do include acute cognitive impairments and potentially long-term memory problems, although with current treatment practices, these are dramatically less than they have been in the past," he added.
Studies conducted in the mid 1980s showed an antidepressant effect of isoflurane anesthesia, but subsequent studies failed to show an effect.
"Unfortunately, these subsequent studies had not followed the original protocol, and we felt that may have contributed to their lack of response," Dr. Weeks explained. "We realized that with advances in anesthesia treatments, isoflurane could be a practical treatment if proven effective."
The investigators modeled the study on the original studies and found a strong antidepressant effect with isoflurane.
During a period of 3 weeks, patients with medication-refractory depression received an average of 10 treatments of bifrontal ECT (20 patients) or a similar number of deep-inhalation isoflurane treatments (8 patients).
Robust Antidepressant Effect
Both therapies produced significant (P < .0001) reductions in depression scores on the Hamilton Rating Scale for Depression24 immediately following the end of treatment, and the benefits persisted at 4 weeks' follow-up. ECT patients had "modestly better" antidepressant effect at follow-up in severity-matched patients, the researchers note.
As expected, ECT caused thinking problems. Immediately after the treatments, ECT patients showed decline in memory, verbal fluency, and processing speed. Most of these ECT-related deficits resolved by 4 weeks. However, autobiographic memory, or recall of personal life events, remained below pretreatment levels for ECT patients 4 weeks after treatment.
In contrast, patients treated with isoflurane showed no performance decrement on any of the traditional cognitive impairment measures at any point. In fact, the isoflurane patients showed significant improvements in some tests, which could be a result of the combined effects of decreased depressive state and practice.
The antidepressant effect of isoflurane was "robust" in this pilot study, said Dr. Weeks, and it confirms the original studies. The isoflurane treatments were also well tolerated.
"Patients awoke from the isoflurane much more rapidly and with less nausea and dramatically less confusion than seen with ECT," he said.
"Thought Provoking"
This is an "interesting and thought-provoking small study that proposes that repeated isoflurane anesthesia has antidepressant effects," Mark S. George, MD, Medical University of South Carolina, Charleston, who was not involved in the research, told Medscape Medical News.
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"The comparison with ECT seems to be not the best control. The next study needs to compare repeated isoflurane anesthesia to repeated anesthesia with something else perhaps methohexital (which is what is commonly used for ECT). If the isoflurane group alone got better, then you would be on to something," he said.
"There is still a very large demand for new and novel treatments for depressed patients who do not respond to current medications," he added.
Echoing Dr. George, Dr. Weeks also cautioned that this was "a small, open-label pilot study, and further research with randomized and blinded studies is required. Our next step is to conduct another pilot study to look at different dosing regimens of isoflurane to guide us in the development of a larger multicenter trial that is randomized and blinded. Further research is necessary to determine what subsets of patients will best respond."
Another anesthetic, ketamine, has also garnered considerable interest in recent years as a potential treatment for depression, as reported by Medscape Medical News.
PLoS One. Published online July 26, 2013. Full article
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