Psychometric properties of a short form of the Affective Lability Scale (ALS-18).

Psychometric properties of a short form of the Affective Lability Scale (ALS) that was developed in a nonclinical sample (i.e., undergraduate students) were examined in a sample of people diagnosed with Cluster B DSM-IV Axis II personality disorders (n=236), other personality disorders (n=180), and healthy comparison participants (n=164). The total score of the ALS-18 score correlated strongly with the original 54-item scale (r = .97) and aspects of convergent and discriminant validity of the ALS-18 subscales (Anxiety/Depression, Depression/Elation, and Anger) were evaluated using self-report measures of affective and psychosocial functioning in the domains of affect intensity, anxiety, anger, and minimization/denial. Clinical utility of the scale was also demonstrated; participants diagnosed with Cluster B personality disorders reported higher affective lability scores, and healthy control participants reported lower scores, relative to individuals with Cluster A or Cluster C personality disorders (p's < .001). Confirmatory factor analyses were conducted and demonstrated reasonably good fit to the data but future research is needed to test the three factor substructure of the ALS-18 against alternative factor models in samples that include clinical and non-clinical participants.