Comorbidities and Diagnosis of Treatment Resistant Depression

In this episode, Dr Anita Clayton and experts discuss complexity of TRD diagnosis.

Before accepting a TRD diagnosis, panelists stressed the importance of first revisiting the underlying diagnosis itself. Conditions like PTSD, bipolar disorder, OCD, ADHD, personality disorders, and substance use disorders can mimic or overlap significantly with MDD — and bipolar disorder alone takes an average of nearly 10 years to correctly identify. These psychiatric comorbidities are often bidirectional, meaning they both influence and are influenced by depression, complicating treatment response.

Medical comorbidities add another layer of complexity. Conditions such as sleep apnea, migraine, diabetes, cardiovascular disease, and metabolic syndrome are all associated with higher rates of depression and poorer treatment outcomes. Panelists highlighted that insulin resistance and chronic GI inflammation likely drive neuroinflammation, potentially being primary contributors to — not merely consequences of — depression.

Given this complexity, one panelist emphasized that TRD is fundamentally a diagnosis of exclusion, requiring thorough medical evaluation including laboratory work and sleep studies, alongside careful assessment of psychosocial factors such as trauma and substance use. The recommended approach: be a medical physician first, a psychotherapist second, and a psychiatrist last — ensuring all contributing factors are identified and addressed before concluding treatment resistance.

In the next episode,“Risk Factors for Treatment Resistant Depression,” panelists discuss key risk factors for TRD — including adverse childhood experiences, family history, gender, age, and inadequate medication trials — while highlighting pseudo-resistance and residual symptoms like anhedonia as critical and often overlooked considerations.