Objectives

This study’s main goal was to assess the efficacy of a structured cognitive-behavioral group program, Growing Pro-Social (GPS), in reducing anger, paranoia, and external shame in male prison inmates.

Methods

In this randomized trial, a treatment group (n = 24) was compared to a control group (n = 24) and both groups were assessed at pre- and post-treatment. Participants answered the State-Trait Anger Expression Inventory, the Paranoia Scale, and the Other as Shamer scale. Treatment effects were tested using ANCOVA with baseline as covariate and condition as fixed factor. Additionally, in order to assess significant clinical change after intervention, the Reliable Change Index (RCI) was computed.

Results

At baseline, no significant differences between conditions were found. ANCOVA with baseline as covariate showed significant differences between groups at post-treatment. When compared to controls, treatment subjects showed lower scores in anger-trait (temperament and reaction subscales) and paranoia. Concerning clinical change, a high percentage of treatment subjects presented improvements in anger, paranoia, and external shame; the majority of controls showed significant deterioration in the same variables. After treatment, differences between groups were observed in the distributions by clinical change categories for anger-trait and its subscales, and paranoia. No differences between groups were found in anger-state and external shame.

Conclusions

These results point out the GPS’s ability to promote significant change in cognitive- and emotional-relevant variables associated with antisocial behavior.