A neuroimaging study of 184 patients with post-traumatic stress disorder (PTSD) has identified unique patterns of brain activity that predict poorer responses to talk therapy (or psychotherapy), the current gold standard and only effective treatment for addressing PTSD. The findings identify a new neurobehavioral subtype within the broad clinical category of PTSD and provide insight into why patients exhibit such different responses to treatment. PTSD is a mental illness that occurs in individuals (often soldiers) who have experienced severe traumatic events or extremely stressful situations. Many patients do not respond to psychotherapy and display highly variable symptoms and behavioral patterns, which has hampered attempts to understand the disorder's underlying biology. Here, Amit Etkin and colleagues used neuroimaging techniques to dig deeper into cognitive function and neurobiology in the brains of patients with PTSD. They evaluated 56 unmedicated patients (who were mostly victims of assault) and 36 controls and found that, compared to the controls, the patients displayed deficits in verbal memory during learning tasks. Interestingly, patients with the most severe verbal deficits showed abnormalities in the VAN (ventral attention network), a sensory system in the brain that regulates attention to stimuli. This observation was repeated in a second cohort composed of 128 combat veterans with PTSD and 117 controls. Importantly, patients who displayed impaired verbal memory and VAN function had poorer outcomes after psychotherapy, while patients with intact verbal memory or normal VAN function were more responsive to psychotherapy. Etkin et al. say future work should investigate whether studying VAN function and verbal memory could predict treatment outcomes in other conditions such as bipolar disorder and drug addiction. In a related Q&A transcript, the authors outline next steps in their quest to establish FDA-cleared brain measures that strongly predict which PTSD patients would be good candidates for treatment.