AIM: Interpersonal traumas are highly prevalent in patients with psychotic disorders. Trauma caused by those close to the patient might have a more profound impact than other types of trauma and may influence early life social functioning. The aim is to investigate the associations between different types of trauma, in particular close interpersonal traumas experienced before the age of 18, premorbid factors and baseline clinical characteristics in a sample of first-episode psychosis patients. METHODS: A total of 191 patients from the 'TIPS' cohort completed assessment with the Brief Betrayal Trauma Survey at their 5 years follow-up interview. RESULTS: Half of the patients reported that they had experienced interpersonal trauma and one-third reported having experienced close interpersonal trauma before the age of 18. Women reported more sexual abuse, physical attacks and emotional and physical maltreatment than men. There were significant associations between early interpersonal trauma and premorbid adjustment and duration of untreated psychosis, but no significant associations with length of education, comorbid substance use or baseline clinical symptomatology. CONCLUSIONS: Close interpersonal trauma before the age of 18 is associated with poorer premorbid adjustment and a longer duration of untreated psychosis. This may indicate that traumatic experiences delay help-seeking behaviour.