The Reinforcement Sensitivity Theory of Personality has as its main foundation a Behavioural Inhibition System (BIS), defined by anxiolytic drugs, in which high trait sensitivity should lead to internalising, anxiety, disorders. Conversely, it has been suggested that low BIS sensitivity would be a characteristic of externalising disorders. BIS output should lead to increased arousal and attention as well as behavioural inhibition. Here, therefore, we tested whether an externalising disorder, Attention Deficit Hyperactivity Disorder (ADHD), involves low BIS sensitivity. Goal-Conflict-Specific Rhythmicity (GCSR) in an auditory Stop Signal Task is a right frontal EEG biomarker of BIS function. We assessed children diagnosed with ADHD-I (inattentive) or ADHD-C (combined) and healthy control groups for GCSR in: a) an initial smaller study in Dunedin, New Zealand (population ~120,000: 15 control, 10 ADHD-I, 10 ADHD-C); and b) a main larger one in Tehran, Iran (population ~9 [city]-16 [metropolis] million: 27 control, 18 ADHD-I, 21 ADHD-C). GCSR was clear in controls (particularly at 6–7 Hz) and in ADHD-C (particularly at 8–9 Hz) but was reduced in ADHD-I. Reduced attention and arousal in ADHD-I could be due, in part, to BIS dysfunction. However, hyperactivity and impulsivity in ADHD-C are unlikely to reflect reduced BIS activity. Increased GCSR frequency in ADHD-C may be due to increased input to the BIS. BIS dysfunction may contribute to some aspects of ADHD (and potentially other externalising disorders) and to some differences between the ADHD subtypes but other prefrontal systems (and, e.g. dopamine) are also important.

Mortensen JA, Rasmussen IA, Håberg A. Trait impulsivity in female patients with borderline personality disorder and matched controls.

Background: Although behavioural activation therapy is effective for depression there is always room for improvement, and also the need to extend this treatment modality to anxiety disorders. Method: A search was conducted for an easy to apply and effective method of achieving these aims. Results: To both enhance the effectiveness of behavioural activation treatment for depression and facilitate its extension to anxiety disorders, it is proposed that the Behavioral Approach/Activation System (BAS) and Behavioral Inhibition System (BIS) be incorporated. BIS/BAS Scales are easy to administer and evaluate ensuring that there is minimal added complexity. Overall, BAS, BAS subscale (Drive, Reward Responsiveness, and Fun Seeking) and BIS scores provide valuable information pertaining to a person's approach and avoidance responses. This general information, plus that derived from specific scale items, can be used to guide more focused and effective behavioural activation strategies. Brief case examples are provided to demonstrate how the BIS/BAS Scales can be applied. Conclusion: BIS/BAS Scales offer an easy to apply and effective means of enhancing behavioural activation therapy for depression and extending this treatment modality to anxiety disorders.