Evidence-b(i)ased psychiatry

PhD Ceremony: Ymkje Anna de Vries, 21 februari, Faculteit Medische Wetenschappen/UMCG

Thesis: Evidence-b(i)ased psychiatry

Evidence-b(i)ased psychiatry

Depressive and anxiety disorders affect about one in five people. Their treatments (antidepressants and psychotherapy) have been studied extensively, but important questions remain unanswered. This dissertation provides answers to some of these questions and shows that the existing evidence base is threatened by biases, such that positive findings are more likely to be published than negative findings. In addition, this dissertation demonstrates several characteristics that predict good outcomes during treatment.

Firstly, negative trials of antidepressants and psychotherapy frequently remained unpublished or were published as if positive, leading to a misleading picture of apparent efficacy. Furthermore, published articles often failed to (accurately) report the occurrence of serious adverse events, such as suicide attempts, that may or may not be related to the treatment. Compounding the problem, negative studies were cited less frequently than positive studies or negative studies that were positively presented.

Secondly, patients with a mild form of some (but not all) anxiety disorders, specifically generalized anxiety and panic disorder, experienced few benefits from antidepressants compared to patients with more severe anxiety. In depressed patients, small improvements in depression after just two weeks of antidepressant treatment predicted good outcomes later on, but which specific symptoms improved did not matter.

In conclusion, this dissertation has clarified that while treatments for depression and anxiety are effective, their efficacy and safety have been inflated by biases. It also showed that patients with more severe generalized anxiety or panic and those with a rapid improvement after antidepressant initiation have the best response to antidepressants.