Toward personalized treatment in psychiatry.

I n recent years, there has been, inspired by developments in other areas of medicine like oncology, an increasing interest in the potential possibilities of personalized medicine in psychiatry. One of the motivating factors behind this interest in the field of mood disorders is the growing awareness among clinicians and researchers that the " one size fits all " approach to the treatment of major depression is not fruitful. An increasing number of reviews and meta-analyses have shown that many acute-phase treatments show comparable efficacy in the treatment of major depression. 1 This finding, originally in the field of psychotherapy research, has become known as the Dodo-bird verdict. 2 The Dodo-bird verdict was interpreted as evidence that all treatments are equivalent because they share common factors. 3 This has led to a lively debate in the literature, with opponents arguing that there is ample evidence for clinically meaningful differences in effect sizes between treatments, indicating that therapy-specific factors, and not common factors, are indeed responsible for these differences. 4 However, a totally different point of view has entered the debate. It has been convincingly argued that clinically meaningful differences between treatments are obscured by the large amount of symptomatic and etiologic heterogeneity within the current DSM-based, categorical, single-entity concept of major depression. By ignoring this heterogeneity and holding on to the " one size fits all " approach, the field will not succeed in increasing the effectiveness of evidence-based treatments for depression. Many have expressed their confidence that results from new fundamental research into etiology, phenomenology, and endophenotypes will yield a more basic understanding of the heterogeneity of depression. 8 suggested a somewhat related but more clinically orientated approach. They introduced a staging approach to mental disorders that could operate as a model for treatment planning. They argued that, within this framework, subjects at high risk for the development of an episode of major depression qualify for different interventions than individuals with a far more advanced stage, eg, multiple episodes with residual symptoms, of the disorder. In recent years, McGorry and colleagues have drawn much attention to the use of clinical staging models in the development and course of psychopathology, 9 which are now available for many psychiatric disorders. 10 In addition to staging, the profiling of patients may be very helpful in deciding which treatment is most indicated for each patient. Profiling refers to characteristics that may further help …