Psychopathy, as described by the triarchic model, encompasses three distinct phenotypes: boldness, meanness, and disinhibition. The current study sought to operationalize these in a sample of 100 Dutch male forensic-psychiatric patients with differing forms of personality pathology who participated in a multi-site randomized clinical trial. Using an established construct-rating approach, triarchic scales were created using items from clinician-rated and self-report versions of the Schedule for Nonadaptive and Adaptive Personality (SNAP) adapted for forensic populations, the SNAP-F. Internal psychometric properties and criterion-related validity were evaluated. SNAP-F-Triarchic Meanness and Disinhibition scales showed acceptable internal consistencies, whereas the Boldness scales (which comprised fewer items) showed lower numbers. The scales showed associations with self-report and interview-based criterion measures largely in line with predictions, with higher validity for criteria assessed in the same measurement domain. Implications of findings for prediction of key outcomes in clinical settings are discussed, along with promising directions for future research.