Adjustment disorder is an underutilised diagnosis in clinical practice. It lacks any well-developed criteria in the current classi cations and is poorly conceptualised. For these reasons it is under- researched. It is conflated with other Axis I diagnoses and many of the treatments offered are not evidence based. The development of ICD-11 and DSM-5 will be an opportunity to establish better diagnostic criteria for this condition, thus enabling research to consider the myriad questions yet to be answered.