The influence of affective temperaments and psychopathological traits on the definition of bipolar disorder subtypes: a study on bipolar I Italian national sample.

UNLABELLED

Affective temperament and psychopathological traits such as separation anxiety (SA) and interpersonal sensitivity (IPS) are supposed to impact on the clinical manifestation and on the course of Bipolar Disorder (BD); in the present study we investigated their influence on the definition of BD subtypes.

METHOD

: Among 106 BD-I patients with DSM-IV depressive, manic or mixed episode included in a multi-centric Italian study and treated according to the routine clinical practice, 89 (84.0%) were in remission after a follow-up period ranging from 3 to 6 months (Clinical Global Impression-BP [CGI-BP] <2). Remitting patients underwent a comprehensive evaluation including self-report questionnaires such as the Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS-A) scale, Separation Anxiety Symptom Inventory (SASI), Interpersonal Sensitivity Measure (IPSM) and the Semi-structured interview for Mood Disorder (SIMD-R) administered by experienced clinicians. Correlation and factorial analyses were conducted on temperamental and psychopathological measures. Comparative analyses were conducted on different temperamental subtypes based on the TEMPS-A, SASI and IPSM profile.

RESULTS

: Depressive, cyclothymic and irritable TEMPS-A score and SASI and IPSM total scores were positively and statistically correlated with each other. On the contrary, hyperthymic temperament score was negatively correlated with depressive temperament and not significantly correlated with the other temperamental and psychopathological dimensions. The factorial analysis of the TEMPS-A subscales and SASI and IPSM total scores allowed the extraction of 2 factors: the cyclothymic-sensitive (explaining 46% of the variance) that included, as positive components, depressive, cyclothymic, irritable temperaments and SASI and IPSM scores; the hyperthymic (explaining the 19% of the variance) included hyperthymic temperament as the only positive component and depressive temperament and IPSM, as negative components. Dominant cyclothymic-sensitive patients (n=49) were more frequently females and reported higher number of depressive, hypomanic and suicide attempts when compared to the dominant hyperthymic patients (n=40). On the contrary, these latter showed a higher number of manic episodes and hospitalizations than cyclothymic-sensitive patients. The rates of first-degree family history for both mood and anxiety disorders were higher in cyclothymic-sensitive than in hyperthymic patients. Cyclothymic sensitive patients also reported more axis I lifetime co-morbidities with Panic Disorder/Agoraphobia and Social Anxiety Disorder in comparison with hyperthymics. As concerns axis II co-morbidity the cyclothymic-sensitive patients met more frequently DSM-IV criteria 1, 5 and 7 for borderline personality disorder than the hyperthymics. On the contrary, antisocial personality disorder was more represented among hyperthymic than cyclothymic patients, in particular for DSM-IV criteria 1 and 6.

LIMITATION

: No blind evaluation and uncertain validity of personality inventory.

CONCLUSION

: Our results support the view that affective temperaments influence the clinical features of BD in terms of both clinical and course characteristics, family history and axis I and II co-morbidities. Hypothetical temperamental subtypes as measured by TEMPS-A presented important interrelationships that permit to reliably isolate two fundamental temperamental disposition: the first characterized by rapid fluctuations of mood and emotional instability, and the second by hyperactivity, high level of energy and emotional intensity. Dominant cyclothymic and hyperthymic bipolar I patients reported important differences in terms of gender distribution, number and polarity of previous episodes, hospitalizations, suicidality, rates of co-morbid anxiety and personality traits and disorders. Our data are consistent with the hypothesis that affective temperaments, and in particular cyclothymia, could be utilized as quantitative, intermediate phenotypes in order to identify BD susceptibility genes.