Does it exist a personality core of mental illness? A systematic review on core psychobiological personality traits in mental disorders.

AIM: Research investigating the relationship between mental disorders and personality traits leads to interesting results. Individuals affected by several mental disorders have been worldwide assessed according to the psychobiological model of personality. This review aims to explore which temperament and character traits are recurrent in mental disorders and to highlight what traits may be shared determinants or consequences of the expression of a mental disorder.
METHODS: Systematic search of Medline database between 1998 and 2011 has been conducted to select the studies exploring the Temperament and Character Inventory (TCI) dimensions in the most relevant axis I psychiatric disorders. Of the 110 studies that were retrieved, 88 met the inclusion/exclusion criteria and were analyzed.
RESULTS: High HA (HA) and low self-directedness are recurrent and can be considered as a "personality core" regardless of the diagnosis. They may be risk factors and relapse-related, they can indicate incomplete remission or chronic course of mental disorders, and consistently influence patients' functioning. Furthermore, they can be modified by medications or psychotherapy and represent outcome predictors of treatments.
CONCLUSION: This "core" may represent a personality diathesis to psychopathology. Relational environment can influence the development of both temperament and character, thus prevention of mental disorders should promote a positive development of these traits. Although further research is needed, psychotherapeutic interventions should be performed also considering that mental disorders could benefit from HA desensitization and SD reinforcement. Finally, these traits may be used to provide diagnostic, prognostic, quality of life and efficacy inferences on psychiatric treatments.