In terms of study method,this study is a three-group quasi-experimental study with pre-test,post-test,and one-month follow-up.The statistical population of the study included all veterans with mental illness Mashhad in 1403,from which 60 people were selected as samples using purposive sampling based on study inclusion and exclusion criteria.In this study,the social relationships questionnaires of McCarthy and Madson(2005),social belonging questionnaires of Hagerty and Patosky(1995), and cognitive flexibility questionnaires of Dennis and Vanderwaal(2010) were used.Also,interpersonal psychotherapy training for the first experimental group and mindfulness for the second experimental group were implemented in 12 separate parallel sessions,but the participants in the control group did not receive any training.Finally,after the measurement stages,data analysis was performed using repeated measures analysis of covariance and Bonferroni post hoc test.The results of the study showed that interpersonal psychotherapy training and mindfulness-based therapy are effective in improving social relationships,sense of social belonging,and cognitive flexibility among veterans of mental and psychiatric disorders.Also,pairwise comparison of experimental groups and time series,no difference was found between the effectiveness of the interventions for all three dependent variables mentioned and the measurement stages,meaning that the effect of both training methods remained the same over time.Consequently,considering the lasting impact of two educational interventions on social relationships,sense of social belonging and cognitive flexibility,the use of these two educational methods in educational centers to enrich the quality of life of neuropsychiatric veterans can be considered.