RecruitingBehavioural interventionTransdiagnostic Behavior Therapy Vs TAU for Adjustment Disorder Following Traumatic Event ExposureAdjustment Disorder (AjD) is the most common mental health condition diagnosed in Active Duty personnel, and is diagnosed following an extreme stress event such as traumatic loss of a comrade, serious accident or injury, or other intense stress event. Despite its high prevalence, no evidence based treatment for AjD has been subjected to randomized controlled trials. This study seeks to build on the research team's pilot work across several disorders study to benefit service members and Veterans with AjD, a highly prevalent but frequently inadequately treated condition. The investigators will compare the effects of Transdiagnostic Behavior Therapy (TBT) vs treatment as usual which is Moving Forward Problem Solving Therapy (TAU-PST) on AjD symptom outcomes. The investigators hypothesize that TBT will result in greater overall symptom reduction compared to TAU-PST.