A Past History Schedule (PHS) for use in conjunction with the Present State Examination (PSE) is described. The PHS/PSE interview enables a rating of 'lifetime ever' psychopathology to be performed. It provides good inter-rater reliability, as well as a satisfactory agreement between retrospective interviews and casenote-based assessment of past psychopathology. The PHS has been devised specifically for use in a family-genetic study of affective illness, but the general approach may be applicable to other categories of psychiatric disorder.