Are personality traits helpful to predict psychosis?

Objective: The aim of this study was to investigate the incidence and specificity of personality traits and personality disorders among patients with psychotic disorders. Making a comparison (regarding to personality traits) between patients with acute transient psychosis and patients with unipolar major depressive disorder with psychotic features was another aim of the study. The relationship between the variety of delusions and personality disorder clusters was also evaluated.

Methods: Fifty-one patients with Acute Transient Psychosis (ATP) (brief psychotic disorder n=25, schizophreniform disorder n=2, psychotic disorder NOS n=24), 41 patients with Major Depressive Disorder with Psychotic Features (MDDPF) and 47 healthy controls were evaluated with a structured interview form based onthe DSM IV (Structured Clinical Interview for the DSM IV, SCID-I, SCID-II). Also the PANSS (Positive and Negative Symptom Scale) and the HDS ( Hamilton Depression Scale) were applied to the patients.

Results: Thirty patients with ATP (58.8%) showed at least one personality disorder comorbidity. The frequency of observed personality disorder clusters was cluster B (39.2%), cluster A, (31.4%), and cluster C (21.6%). The most common personality disorders among the patients with ATP were borderline (27.5%) and paranoid (27.5%). Twenty-two patients with MDDPF (48,9%) had at least one personality disorder comorbidity. The most frequent personality disorder cluster was cluster C (40%); followed by cluster B (20%) and cluster A (17.8%). When the two diagnostic groups were compared, cluster B, narcissistic, schizotypal and antisocial personality disorders were observed more frequently in the ATP group and the cluster C and avoidant personality disorders were more frequently observed in the MDDPF group. Paranoid delusions had higher rates in cluster A and other delusions (like jealousy, erotomanic, and mystic delusions) had higher rates in cluster B.

Conclusion: In spite of the high rates of personality disorders in both diagnostic groups, the same disorders were also observed in people with no personality disorders. ATP and MDDPF did not seem to have a relationship with any personality disorder. Nevertheless, some personality disorders (narcissistic, schizotypal, and avoidant) can contribute to ATP and MDDPF by different mechanisms. Performing a personality assessment after the first year of improvement of the post psychotic symptoms might have given more accurate results. On the other hand, it could be said that, personality traits may have an effect on delusions.