Why is psychiatry prone to fads?

Psychiatry has long been prone to fads. The main reason is that mental illness is poorly understood and can be difficult to treat. Most diagnostic fads have involved the extension of well-known categories into broader spectra. The most prominent treatment fads have involved the overuse of pharmacological interventions and a proliferation of methods for psychotherapy. The best antidote to fads is a commitment to evidence-based psychiatry.