Clinical characteristics and socio-demographic features of psychotic major depression

Background: Psychotic major depression (PMD) is a special subtype of depression with a worse prognosis. Previous studies failed to find many differences among patients with PMD versus those with non-psychotic major depression (NMD) or schizophrenia(SZ). This study compared psychotic major depression with non-psychotic major depression and schizophrenia based on sociodemographic factors (including season of conception) and clinical characteristics. We aimed to provide data to inform clinical diagnoses and etiology research. Methods This case–control study used data for patients admitted to Shandong Mental Health Center from June 1, 2016 to December 31, 2017. We analyzed cases that had experienced a PMD episode (International Classification of Diseases, Tenth Revision codes F32.3, F33.3), NMD (F32.0–2/9, F33.0–2/9), and SZ (F20–20.9). Data were collected on sex, main discharge diagnosis, birth date, ethnicity, family history of psychiatric diagnoses, marital status, age at first onset, educational attainment, allergy history, and existence of trigger events. Results Patients with depression with a primary school/below education (odds ratio [OR] 0.397, CI: 0.18–0.874) and without a family history (OR 0.557, CI: 0.332–0.937) were less likely to have psychotic symptoms than other patients. Compared with patients with PMD, a primary school/below education (OR 3.646, CI: 1.65–8.053), no allergy history (OR 2.2, CI: 1.152–4.2), trigger events experienced before first onset (OR 2.428, CI: 1.528–3.859), being unmarried (OR 0.3, CI: 0.104–0.871), and an earlier age at first onset (OR 0.931, CI: 0.911–0.952) were features of SZ. Conclusion PMD and NMD are similar in terms of patients’ demographic variables and clinical characteristics, whereas there are differences between PMD and SZ. The significant factors we identified may point to underlying heterogeneity of these diseases.