Purpose: The purpose of this study was to evaluate the 
effectiveness of forgiveness training and mindfulness training 
on cognitive flexibility in men with substance abuse disorders.
Materials and methods: The method of quasi-experimental 
research was pre-test, post-test and follow-up with a control 
group. The statistical population included all male drug users 
who referred to the de-addiction camp in Zabul city in 2019, 
60 of whom were selected by convenience sampling and 
randomly assigned to three groups, two experimental and 
control groups. The experimental group of forgiveness 
training received 8 sessions and the experimental group of 
mindfulness training received 12 training sessions. The data 
were collected using the cognitive flexibility questionnaire 
and analyzed using the variance analysis method with repeated 
measurements.
Findings: The results showed that men with substance abuse 
disorder who underwent forgiveness training had more 
flexibility than the control group who did not receive training. 
And men with substance abuse disorder who underwent 
mindfulness training had more flexibility than both the control 
group that was not trained and the group that underwent 
forgiveness training. And these results remained stable in the 
3-month follow-up.
Conclusion: In this research, forgiveness and mindfulness 
training has a significant effect on the cognitive flexibility of 
men with substance abuse disorder, and compared to the two 
methods of mindfulness training and forgiveness training, the 
mindfulness method has a significantly higher score in 
cognitive flexibility than forgiveness training. in men with 
substance abuse disorder.