Transcranial sonography (TCS) revealed reduced brainstem raphe (BR) echogenicity in major depressive disorder (MDD). Here, it was studied whether BR echogenicity discriminates MDD and adjustment disorder with depressed mood (ADDM), and whether BR echogenicity relates to depression severity or treatment responsivity. For this, 15 patients with single episodes of MDD (MDDs), 22 with recurrent MDD (MDDr), 15 with ADDM, and 50 healthy controls were investigated with TCS. Frequency of reduced BR echogenicity was similar in groups MDDs (53%), MDDr (50%) and ADDM (60%), but significantly lower in the controls (8%). Patients with reduced BR echogenicity had lower scores on the 21-item Hamilton Depression Rating Scale and the Motor Retardation Scale, compared with patients with normal BR echogenicity. BR echogenicity scores were significantly lower in SSRI responders to serotonin reuptake inhibitors (SRI) than in non-responders. Reduced BR echogenicity indicated SSRI responsivity with 70% sensitivity, 88% specificity and a positive predictive value of 88%. No impact of age, gender or antidepressant medication on BR echogenicity was found. These results indicate that reduced BR echogenicity is not related to diagnostic category of depressive state. Reduced BR echogenicity might reflect a pathology predisposing to a certain subtype of depression characterized by less psychomotor retardation and better responsivity to SRI.