The Effectiveness of Compassion-based Acceptance and Commitment Group Therapy on Adjustment and Happiness in Patients with Major Depression Disorder

: The aim of this study was exploring the effectiveness of compassion-based acceptance and commitment group therapy on adjustment and happiness in patients with major depression disorder. The research method was quasi-experimental with pre-test-post-test, with control group and follow-up. The sample was selected randomly from patients with major depression disorder in Jam city, Pardis and Naft towns, and randomly assigned into experimental and control groups. Compassion-based Acceptance and Commitment Group Therapy was performed for the experimental group, but the control groups did not receive any specific intervention. The research instruments included Sohrabi and Samani (2011) adjustment questionnaire and Argil (2001) happiness scale. The results of analysis of covariance (ANCOVA) with repeated measures showed that intervention increased adjustment in the experimental group, so that intervention in the second stage increased the adjustment compared to the first stage, this is while there was not difference between second and third stages. So it can be said that the treatment in patients with major depression disorder was more effective in the post test. Also, the intervention increased happiness in the experimental group, so that intervention in the posttest increased the happiness compared to the pretest, this is while there was not difference between posttest and follow up. So it can be said that the treatment in patients with major depression disorder was more effective in the post test. acceptance and commitment group therapy on cognitive regulation of positive emotions and happiness in patients with depressive disorder. For example, Saeedi (2019) in his research entitled ‘Assessing the effectiveness of commitment-based therapy and acceptance on social and emotional adjustment of mothers of children with mental and physical disabilities’ showed that commitment and acceptance therapy is effective on social and emotional adjustment of mothers. in a study investigated the effect of happiness education on depression and suicidal ideation in students. The results showed that the rate of depression and suicidal tendencies are significantly different between the experimental and control groups. Ansari (2018) in his study entitled ‘The effectiveness of acceptance and commitment therapy on mental flexibility, cognitive regulation of emotion and mental adjustment in people with stuttering’ showed that treatment based on acceptance and commitment is effective in improving speech improvement in patients with stuttering. Manshaee Hoseini in a study entitled ‘The effectiveness of child-centered mindfulness training on social adjustment and depressive symptoms in children with depressive disorder’ showed that child-centered mindfulness training has an effect on social adjustment and depressive symptoms in children with depressive