The authors reviewed NIHR-funded clinical trials and found that adverse events were rarely reported in studies evaluating psychological treatments, despite growing recognition that such interventions can sometimes cause harm. They argue that existing adverse event frameworks were largely developed for drug trials and may be poorly suited to capturing harms specific to psychological therapies. The paper proposes a broader conceptualisation of harm, including sustained deterioration, increased symptoms, dependency, or negative impacts on relationships and functioning. Overall, the review highlights the need for more systematic monitoring and reporting of adverse events in psychological treatment research.