--- - |2 Abstract Adjustment disorders (AD) and complicated grief (CG) are serious mental conditions that have a high prevalence and are associated with significant impairments in social and work functioning. Recently, these categories have been better specified in the new ICD‐11 proposal. Empirical research on the efficacy of treatments for these problems is scarce. This study aims to offer long‐term efficacy data from a between‐groups controlled study that compares two treatment conditions (AD‐protocol applied in a traditional way: N= 18; and the same protocol supported by virtual reality‐VR‐: N =18) and a waiting list (WL) control group (N =18). Both treatment conditions resulted in statistically significant improvements on both primary and secondary outcome measures, with large effect sizes, and this improvement did not occur in the WL. These changes were maintained in both treatment conditions in the medium (6‐month) and long term (12‐month follow‐up). Larger effect sizes were achieved in the VR condition in the long term. Furthermore, clinically significant change estimations on the primary outcome measures showed an advantage for the VR condition This is the first controlled study to compare a traditional face‐to‐face protocol for the treatment of stress‐related disorders to the same protocol supported by VR and a WL control group. - Clinical Psychology & Psychotherapy, Volume 0, Issue ja, -Not available-.