Scientists dismiss many open studies in psychiatry with skepticism for good reason; they are often falsely positive because of something called the “placebo effect.” That is, if you take 50 depressed teenagers and give them vitamin D and 50% improve, one has no way of knowing if it was the vitamin D or the placebo effect.
Placebo effects occur for lots of reasons, mainly because psychiatric diseases, with few exceptions, tend to get better over time. This is particularly true of major depression, where the placebo response may be as high as 50% (for reasons that are unclear, researchers see less placebo effect in obsessive-compulsive disorder). In depression, the placebo effect means that almost half your subjects will tend to improve with placebo, or the measurement scales you use will show a 50% improvement in the average patient.
That said, I am encouraged by a just-released Swedish open trial of vitamin D treatment of depression in 48 teenagers. I’m encouraged for a couple of reasons. First, a previous controlled trial using mood questionnaires by Professor Vieth showed improvements. Two, younger brains tend to be more plastic, less set in their way and more amenable to change. Third, the treatment, vitamin D, is innocuous; it is not a drug. Fourth, a number of the teenagers had vitamin D levels very low (<10 ng/ml).
Högberg G, Gustafsson SA, Hällström T, Gustafsson T, Klawitter B, Petersson M. Depressed adolescents in a case-series were low in vitamin D and depression was ameliorated by vitamin D supplementation. Acta Paediatr. 2012 Feb 28.
Thirty-five of the kids had “severe depression,” but I was happy to see that only five kids were given drugs; almost all were given counseling, which may itself explain the improvement. The vitamin D dose was low for teenagers (who need adult doses of vitamin D), although the average teenager got his or her levels up to around 35 ng/ml. I think 50 ng/ml or even higher would have been better.
This is an important study as it helps with dose finding, scales used, and response rates that the placebo effect may or may not explain. Given the known placebo effect in depression, I suspect this is a negative study, but I have hope with higher doses and longer treatment periods some teenagers would find it easier to feel better. However, it is clear from the study that 54 depressed adolescents are feeling better in Stockholm, hopefully, in part, because of vitamin D. If nothing else, as they return to their caves to play video games, their bones are suffering less damage then they were previously.