The stability of psychopathic personality disturbance (PPD) has important theoretical implications for developmental criminology and population heterogeneity perspective assertions that psychopathy is a key measure of criminal propensity. Data from the Pathways to Desistance Study ( n = 1,354) were used to examine short-, moderate-, and long-term reliable change in symptoms of PPD measured via the Youth Psychopathic Traits Inventory (YPI). Youth scoring highest on the YPI at the baseline assessment were most likely to experience reliable decreases in test scores. Binomial regression analyses showed that a reliable decrease in YPI test score was associated with decreased odds of endorsing additional offenses. Findings contrasted the adolescent “fledgling” psychopathy perspective and indicated that individuals scoring high on the YPI are the group most likely to experience reliable decreases in test scores, especially over a longer follow-up period.