Affect lability scale (ALS-18) and ADHD: incremental validity of depression, depression/anxiety and anger in the predictions of inattention and hyperactivity/impulsivity in adults

Abstract Affect lability, or difficulties in emotional regulation, has been suggested to be a defining factor in ADHD presentations, with previous studies identifying a relationship between affect lability and ADHD. However, the relationship between different dimensions of lability and ADHD dimensions has not been explored. This study aims to examine whether the three affect lability dimensions– depression/elation (D), depression/anxiety (D/A), and anger (A)– have incremental validity in predicting ADHD symptoms of inattention (IA) and hyperactivity/impulsivity (HI). A total of 558 adults aged 18–65 (Mage = 32.75; 18.8% men) from the general community completed the ALS-18 and the Current Symptom Scale (CSS). A structural equation model (SEM) approach was used to evaluate incremental validity. For a comprehensive evaluation, three different SEM models corresponding to different orders of entry of the predictors were computed to assess the incremental validity of the three ADHD dimensions. Overall, the findings showed that both D/A and D provided comparable incremental validity in the predictions of IA and HI, whereas A did not predict IA and HI. Therefore, D/A and D are important affect lability dimensions for the prediction of ADHD. These results suggest that not all components of affect lability were equally important in explaining ADHD symptoms, indicating the need to consider specific dimensions of affect lability for a more accurate understanding and treatment outcomes. Future research should further explore these relationships, incorporating broader affect lability dimensions and larger samples to generalize findings more effectively.