Does neuroanatomy predict ECT response?

1. Structural neuropathologic abnormalities have been associated with severe psychiatric illnesses, including bipolar disorder, major depressive disorder, and schizophrenia. In the latter, ventricular enlargement has been variably associated with symptom severity and poor treatment response. In patients with severe depressive disorders, the relationship between cortical and subcortical pathology and ventricle enlargement, symptom severity, and response to treatment is far from clear. 2. The present study investigated the relationship between structural CNS pathology, symptom severity and treatment response in patients undergoing ECT. It was hypothesized that patients with greater neuroanatomic abnormalities would demonstrate greater initial symptom severity and poorer response to ECT. 3. The subjects were 57 patients with unipolar or bipolar depression admitted for ECT treatment. Symptom severity was quantified using the Hamilton Depression Rating Scale (HRSD) at baseline and post-ECT. 4. Lateral and third ventricle-brain ratio (LVBR, 3VBR) were determined from CT scans and cortical atrophy was rated by a faculty neuroradiologist. 5. Contrary to our first hypothesis, structural pathology was not associated with baseline symptom severity. In terms of treatment response, the number of treatments required to achieve benefit was correlated with larger 3VBR; CT variables were not related to total post-treatment or change in HRSD score. Third ventricle enlargement may be an index of generalized pathology or regional brainstem abnormalities that influence ECT response rate by limiting individual seizure efficacy or neurochemical responsiveness, thereby necessitating a greater number of ECT treatments, without significant impact on overall response.