Sensation Seeking in major depressive patients: relationship to sub-threshold bipolarity and cyclothymic temperament

Background: High levels of sensation seeking (SS) have been traditionally reported for lifetime bipolar disorder (BD) and/or substance use disorder (SUD) rather than major depressive disorder (MDD). Nonetheless, a renewed clinical attention toward the burden of sub-threshold bipolarity in MDD, solicits for a better assessment of "unipolar" major depressive episodes (MDEs) via characterization of putative differential psychopathological patterns, including SS and predominant affective temperament. Methods: Two hundred and eighty currently depressed cases of MDD and 87 healthy controls were screened using the Zuckerman's sensation seeking scale-Form-V, the Hypomania Check List-32-item (HCL-32), the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Auto-questionnaire-110-item, the Barratt Impulsivity Scale-11-item, the State-Trait Anxiety Inventory modules and the Structured Clinical Interview for DSM-IV axis-I disorders. Cases were divided into HCL-32(+) (sub-threshold bipolar)/HCL-32(-)("true" unipolar depressed) depending on the HCL-32 total score. Results: Upon correlation and multivariate regression analyses, the HCL-32-(+) patients showed the highest levels of SS, higher prevalence of cyclothymic temperament, and higher rates of multiple lifetime axis-I co-morbidities, including SUD. Limits: Recall bias on some diagnoses, including BD, grossly matched healthy control group, lack of ad-hoc validated measures for ADHD, SUD, or axis-II disorders. Conclusions: In our sample, the occurrence of higher levels of SS in "sub-threshold" bipolar cases outlined a differential psychopathological profile compared to DSM-defined "true unipolar" cases of MDE. If confirmed by replication studies, these findings may aid clinicians in delivering a more accurate diagnosis and a safer use of antidepressants in some MDD cases