1. Depression is measured by severity on the MADRS scale. But the Ketamine group seems to have started out less depressed than the Placebo group. Thus the placebo group had further to fall. Normally this will be adjusted away when calculating treatment effect, but seems not to have been done here. I think if it had been done ketamine would have had a slight (but highly nonsignificant) edge over placebo in the linear model.
2. Many of the patients are already on some kind of depression treatment, going into the study. This is kind of odd.
3. 5 of the patients in the ketamine group had experience with ketamine previously, but only 1 in the placebo group. Were those having experience with ketamine insensitive to it, as they seem to have become depressed again? Or did they believe they'd be insensitive to it?
4. Sample sizes are small, and usually larger sample sizes are needed to see efficacy in depression trials, even in highly efficacious treatments.
5. The so-called routine surgery may have been fairly anxiety-inducing for the patients and getting it done could have made them feel quite a lot better by itself. That effect may be stronger than any medication effect.
6. Yeah, of course, this doesn't tell anything on whether ketamine has efficacy against MDD or not. Just that it could look like the efficacy of ketamine +(extra) anesthesia is about the same as anesthesia by itself against MDD, upto 14 day post-treatment.
1. Depression is measured by severity on the MADRS scale. But the Ketamine group seems to have started out less depressed than the Placebo group. Thus the placebo group had further to fall. Normally this will be adjusted away when calculating treatment effect, but seems not to have been done here. I think if it had been done ketamine would have had a slight (but highly nonsignificant) edge over placebo in the linear model.
2. Many of the patients are already on some kind of depression treatment, going into the study. This is kind of odd.
3. 5 of the patients in the ketamine group had experience with ketamine previously, but only 1 in the placebo group. Were those having experience with ketamine insensitive to it, as they seem to have become depressed again? Or did they believe they'd be insensitive to it?
4. Sample sizes are small, and usually larger sample sizes are needed to see efficacy in depression trials, even in highly efficacious treatments.
5. The so-called routine surgery may have been fairly anxiety-inducing for the patients and getting it done could have made them feel quite a lot better by itself. That effect may be stronger than any medication effect.
6. Yeah, of course, this doesn't tell anything on whether ketamine has efficacy against MDD or not. Just that it could look like the efficacy of ketamine +(extra) anesthesia is about the same as anesthesia by itself against MDD, upto 14 day post-treatment.