Transcranial sonography of the brainstem raphe: A rapid tool to assess the long-term risk of violent suicidal behavior in patients with major depression

OBJECTIVE: To assess the relationship between ultrasonographic changes in midbrain structures and subsequent violent suicidal behavior. METHODS: We conducted a retrospective analysis of a previously reported cohort of 46 patients (36 women; age 54.9 ± 11.7 years) with major depression who had been prospectively observed over a ten-year period to assess the risk of developing Parkinson's disease. At study entry, all patients underwent transcranial B-mode sonography to grade the echogenicity of the midbrain raphe and substantia nigra. The outcome measure was the first occurrence of violent suicidal behavior, i.e. a serious suicide attempt or completed suicide. RESULTS: At baseline, four patients were found to have grade 1 raphe echogenicity (invisible), 23 had grade 2 (weakly echogenic), and 19 had normal grade 3 (strongly echogenic). The visually graded echogenicity correlated well with the digitally analyzed echo-intensity (p < 0.001). Three (75%) patients with echogenicity grade 1 subsequently attempted or completed suicide, as did five (22%) with grade 2, but none with grade 3 (Kaplan-Meier analysis, log-rank test, p < 0.001). The latency period did not differ between echogenicity grade 1 and 2 (34.7 ± 30.9 vs. 22.6 ± 19.7 months, p = 0.59). Overall, patients with reduced raphe echogenicity were less likely to be free of subsequent violent suicidal behavior (3 years: RR, 0.78; 95% CI, 0.64-0.95; p = 0.034; 10 years: 0.70; 0.55-0.90; p = 0.014). No sex differences were found. Echogenicity of the substantia nigra did not improve the prediction of suicidal behavior. CONCLUSIONS: Reduced echogenicity of the midbrain raphe indicates an increased risk of subsequent violent suicidal behavior in patients with major depression.