Biomarkers in psychiatry need to be mechanistic, not simply predictive of course and outcome? —No.
The opportunity for neuroscience-based approaches to impact clinical psychiatry has never been greater, yet biological measures have had almost no impact on psychiatric practice.
One would like to be able to say, “Mrs Jones, your depression test has come back and, with the current treatment, you have a 90% chance of being symptom free within the next 6 weeks.” However, this statement is still science fiction. It is not for a lack of trying; brilliant minds have used technology with increasingly large study populations, yet practical results that change how we treat patients have been sorely lacking. Hopes for a neuroscience-based understanding of mental illness to bring better cures have been raised; however, there is no biological diagnostic or prognostic test in psychiatry and most interventions, behavioral or pharmacological, have been discovered serendipitously.
Paulus MP. Pragmatism Instead of MechanismA Call for Impactful Biological Psychiatry. JAMA Psychiatry. 2015;72(7):631-632. doi:10.1001/jamapsychiatry.2015.0497