This study assessed whether decrease in depressive symptoms after group psychodynamic psychotherapy was due to change in neuroticism score.

Patients were treated with group psychodynamic psychotherapy lasting 12 weeks. Every working day patients had 2 therapeutic sessions of 1,5 hour each. Personality trait neuroticism was measured with Eysenck Personality Questionnaire - Revised (EPQ-R), depressive symptoms with Depression Scale of Symptoms Checklist 90 - Revised (SCL-90-R) questionnaire.

Of 139 patients included in the study, 110 patients (79.1%) completed it. They were 37 men and 78 women, all with mean age of 34.25 years old. 64 patients were diagnosed with a neurotic disorder (ICD-10/F4), 28 with a personality disorder (F6), 15 with both a personality and a neurotic disorder and 3 with depression (F32) with personality disorder. In total 53 patients were on medication, mainly selective serotonin reuptake inhibitors.

Initial mean neuroticism score was 18.9, and after treatment it was 17.6. This difference is statistically significant as a change (t = 2.88, p = 0.005), but not as an independent mean value (t = 1.9, p = 0.06). Difference in severity of depressive symptoms is far more considerable: before treatment 2.08, after treatment 1.61, and it is statistically significant in comparison as dependent (t = 5.29, p = 0.000001), as well as independent (t = 3.53, p = 0.0005).

Looking at proportion of the change, neuroticism score dropped by 7%, whereas depressive symptoms score dropped by 22.6%. We can say that change of depressive symptoms severity is caused mainly by other factors than change in personality trait neuroticism score.