Over the last 15 years, ketamine, originally developed as an anesthetic in the 1950s, has undergone a resurgence in medical circles for its remarkable effects treating major depression. Now a team of researchers has completed the first study of the drug in adolescents, revealing strong remission rates for those young subjects with treatment-resistant depression.

A huge amount of research is currently underway investigating the compelling, and novel, effects of ketamine on depression. The entirely unique way the drug interacts with the brain is revealing new and exciting pathways for neuroscientists investigating everything from fatigue to suicidal thoughts. However, very little study has been undertaken into the effects of the drug on adolescents.

The impetus behind the research came from the hypothesis that the enhanced neuroplasticity of adolescent brains could help extend the duration of efficacy in ketamine treatments for depression, and potentially result in long-term benefits. The researchers write in the study that, "adolescence is a key time period for emergence of depression and represents an opportune and critical developmental window for intervention to prevent negative outcomes."

The study recruited 13 subjects aged between 12 and 18. All subjects were clinically diagnosed with treatment-resistant depression, meaning they had failed to respond to at least two prior antidepressant trials. The treatment involved six ketamine infusions over the course of two weeks, with doses based on body weight.

One week after the treatment, five of the 13 subjects displayed decreases in their symptoms to a level that could be clinically considered as remission. At the six week point following the treatment three subjects still displayed continued remission.

These results are slightly lower than what has been reported in adult studies, and the researchers hypothesize that dose could be a major factor in improving adolescent responses. It's noted that the first five subjects in the trial were dosed according to an ideal body weight, and not an actual body weight. This means these subjects, four of which were overweight, received smaller doses than if it were actually calculated on real body weight. All five of these initial subjects displayed non-responsive results.

The remaining eight subjects in the study were then dosed at a rate relative to their actual body weight. Five of those eight subjects displayed successful remission responses. This suggests that dosing based on ideal body weight, which is known to be effective in adult subjects, may not be appropriate for adolescent subjects.

While these results certainly confirm ketamine as offering significant benefits in treating major depression, there still is much work to be done to better understand the optimal dose and schedule for administering the drug, especially in younger patients. Larger, and more long-term adolescent studies need to be completed to reveal how this drug interacts with growing, younger brains.

The new study is published in the Journal of Child and Adolescent Psychopharmacology.