Abstract
We investigate the efficacy of intensive three principles correctional counseling (3PCC) for improving the mental health of people in an English prison. 175 prison residents receiving intensive 3PCC and 127 control participants completed the Three Principles Inventory; Warwick-Edinburgh Mental Well-Being Scale; Purpose in Life Test; and PROMIS depression, anxiety, and anger inventories. Compared with the control group, participants receiving intensive 3PCC showed a significant increase in three principles understanding, mental wellbeing, and purpose in life, and a significant decrease in depression, anxiety, and anger. At five-month follow-up each benefit shown at posttest was either maintained or significantly improved.