Can Ketamine Treat Acute Suicidal Ideation?
InpharmD™ Clinical Literature Summaries — S3E11
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With this podcast, we recap innovative, practice changing studies in ten minutes or less. And remember, nothing here is medical advice; we just present the evidence and our (sometimes hot) takes.
Can Ketamine Treat Acute Suicidal Ideation?
You’ve probably heard rumors of ketamine being used to treat mental illness. This drug seems to do it all these days, from anesthesia to pain control to depression. But can it help people on the brink of suicide?
Ketamine is an NMDA antagonist and has complex interactions with our central nervous system. We’re still figuring out just how it might work for all the uses we’re finding for it. A French team of researchers decided to see if they could find yet another use for this drug.
They randomized over 150 adult patients who’d been admitted to the hospital for suicidal ideation to receive either ketamine as two intravenous infusions one day apart or a matching saline placebo. This was of course in addition to standard treatment. Then at day 3, they looked at how many patients were in full suicidal remission.
We do need to keep in mind that this study excluded patients with schizophrenia, psychotic disorders or substance dependence. One aspect of this study we really like is that they stratified randomization by three groups of psychiatric disorders. Either depression, bipolar or other psychiatric disorder. This means that for their results, they can look specifically at these subgroups with less risk of confounding.
For the primary outcome of suicidal remission at day 3, they found ketamine to be effective with many patients responding within hours. Over 60% of patients achieved suicidal remission with ketamine as compared to just over 30% with placebo. This was statistically significant. This beneficial effect was driven primarily by the bipolar subgroup, as neither the depression or other psychiatric disorders group had a statistically significant change in suicidal ideation.
The researchers continued to follow these patients for 6 weeks to see if their remission continued. By week 6, the ketamine arm maintained a high rate of remission at around 70%, but the placebo arm gained back a lot of ground with a remission rate of over 55%. So by week 6, the difference was no longer statistically significant, but this wasn’t because ketamine stopped working, it was because people in the placebo group felt better.
Now what do we make of all this? Well first-lets keep in mind that suicidal ideation and suicide attempts are different things. By week 6, both the ketamine and placebo groups had attempted suicide at similar rates. So while it seems to work for suicidal ideation, it didn’t really change the action itself. This could just be because the study was not powered to look at true suicide attempts as these are more rare than ideation.
Something else to consider is the effect being seen only in the bipolar subgroup. It’s possible that when analyzing by subgroup, the study became under-powered, so we do need to take this result with a grain of salt. In an ideal study, there would be enough patients in each subgroup to maintain appropriate power to detect an effect.
So while ketamine was generally well tolerated, it does have the potential for abuse, so the benefits must be weighed against the risks.
In the end, what we need is a larger study to determine if ketamine can have the potential to actually decrease suicide attempts. This is a key end point that was not adequately examined in this study. Until then, ketamine does show promise, but still has more of a story to tell!
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