Traumatic experiences have been positively associated with both severity of attenuated psychotic symptoms in individuals at high risk (HR) for psychosis and transitions into psychotic disorders. Our aim was to determine what characteristics of the trauma history are more likely to be associated with individuals at HR. The Trauma History Screen (THS) was used to enable emphasis on number and perceived intensity of adverse life events and age at trauma exposure. Sixty help-seeking individuals who met HR criteria were compared to a random sample of 60 healthy volunteers. Both groups were aged 16–35 and resided in the same geographical location. HR participants experienced their first trauma at an earlier age, continued to experience trauma at younger developmental stages, especially during early/mid adolescence and were exposed to a high number of traumas. They were more depressed and anxious, but did not experience more distress in relation to trauma. Both incidences of trauma and age at which trauma occurred were the most likely predictors of becoming HR. This work emphasises the importance of assessing trauma characteristics in HR individuals to enable differentiation between psychotic-like experiences that may reflect dissociative responses to trauma and genuine prodromal psychotic presentations.