Temperaments linked to clinical features and course in bipolar I disorder
MedWire News: Research suggests that cyclothymic and hyperthymic temperaments are associated with differences in clinical features in patients with bipolar I disorder, such as number of hospitalizations, disease course, family history, and comorbid disorders.
Although there has been a great deal of research over the past century into the relationship between affective temperament and mood disorders, the majority of investigation has concentrated on bipolar II disorder, while that carried out in bipolar I disorder patients has focused on temperament and mixed states.
To investigate further, Giulio Perugi, from the University of Pisa in Italy, and colleagues studied 89 bipolar I disorder patients who were in remission at 3-6 months after treatment in accordance with routine clinical practice.
The participants were assessed using the Clinical Global Impression-BP, 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) questionnaires.
The team reports in the Journal of Affective Disorders that 65% of the variance in scores was explained by two factors. The first explained 46% of the variance and was characterised by depressive, cyclothymic, and irritable temperament, as well as SASI and IPSM total scores. The second, explaining 19% of the variance, included hyperthymic temperament as the only positive component, with depressive temperament and IPSM scores as negative components.
Dominantly cyclothymic-sensitive patients were more likely to be females, have greater numbers of depressive and hypomanic episodes, and suicide attempts, and be more likely to have first-degree relatives with a history of mood and anxiety disorders, while hyperthymic individuals had more manic episodes and hospitalizations.
Axis I lifetime comorbidities of Panic Disorder/Agoraphobia and Social Anxiety Disorder were more common in hyperthymic than cyclothymic patients. In addition, cyclothymic patients more often met the criteria for axis II borderline personality disorder, while hyperthymic patients more often had antisocial personality disorder.
The researchers conclude: "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 bipolar disorder susceptibility genes."
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By Liam Davenport