Background
The weak regulation, or “dysregulation”, of the Behavioural Activation System (BAS) is implicated in the development and recurrence of bipolar disorder. However, there has been a lack of prospective studies investigating the predictive role of BAS dysregulation in relation to bipolar-vulnerability. Furthermore, no studies have tested the prospective predictive utility of the DYS self-report measure of BAS dysregulation in an analogue sample. The goal of the current study was to redress this gap. Methods Participants (n = 127) completed baseline self-report measures of mood symptoms (Internal States Scale [ISS]), the Hypomanic Personality Scale (HPS), behavioural activation, inhibition and dysregulation of BAS (BIS/BAS and DYS), and at six months, the Mood Disorders Questionnaire (MDQ). Results Linear regression analysis indicated a significant main effect of BAS Dysregulation, and a significant interaction between BIS and BAS Fun Seeking, on prospective MDQ scores whilst controlling for baseline mood symptoms and HPS scores. The interaction effect indicated that the relationship between high BAS Fun Seeking and follow-up MDQ scores was strongest when BIS scores were high, whilst the lowest MDQ scores were observed for a combination of low BAS Fun Seeking and high BIS. However, DYS scores were the stronger predictor of MDQ scores compared to the BAS Fun Seeking and BIS interaction. Conclusions Bipolar-vulnerability is prospectively associated with heightened BAS Dysregulation, as measured by the DYS subscale, similar to prior findings in clinical samples. Further research investigating the longer-term associations between BAS Dysregulation with the development of clinically significant bipolar mood symptoms is required.