Objectives: The present study was conducted to investigate the effectiveness of acceptance and commitment group therapy in cognitive flexibility, suicidal ideation, depression, and hopelessness in conscripts. Methods: In an experimental study with a pretest-posttest control group design, 60 conscripts were selected through convenience sampling method from military centers in Khorasan Razavi in 2019 and were randomly assigned to experimental and control groups, each containing 30 individuals. The experimental group received acceptance and commitment group therapy in eight 90-minute weekly sessions and the control group received no treatment. In the pretest and posttest, Cognitive Flexibility Inventory (CFI), Beck Scale for Suicide Ideation (BSSI), Beck Depression Inventory-II (BDI-II) and Beck Hopelessness Scale (BHS) were implemented for both groups. Data analysis was performed using the independent ‎groups ‎t test and analysis of covariance. Results: The results indicated that acceptance and commitment group therapy significantly leads to enhanced cognitive flexibility and its components (P = 0.001) and reduced suicidal thoughts (P = 0.001), depression (P = 0.001) and hopelessness (P = 0.002) compared to the control group.

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