Treatment-resistant depression (TRD) is a long-standing concept in psychiatry, yet it still lacks a shared and consistent definition. Since its introduction in the 1970s, TRD has been described through various staging models and regulatory criteria that differ across studies and guidelines, leading to significant methodological and clinical variability. More than 150 distinct definitions have been identified in the scientific literature, making it difficult to compare results, synthesise evidence and clearly identify patients for advanced treatments.
Regulatory agencies in Europe and the United States adopt different operational criteria, further complicating research and access to care. In addition, current definitions tend to focus mainly on pharmacological response, often neglecting functional, psychological and contextual aspects of depression. Recent perspectives therefore suggest moving beyond a rigid, drug-centred definition of TRD toward a broader, dimensional framework that includes difficult-to-treat depression and supports a more personalised approach to care.
Walter Paganin – Studio Psicologia Signorini, Guidonia, Lazio, Italy.