However, because of the time and expense required to administer a clinical interview, epidemiologic type studies often use clinical interviews designed for administration by lay interviewers (Composite International Diagnostic Interview [CIDI] or the Diagnostic Interview Schedule [DIS]) or self-report questionnaires that measure symptoms and mood rather than illness and disorder. The SCID is a semi-structured interview for making the major Axis I DSM-III-R diagnoses. It is administered by a clinician and includes an introductory overview followed by nine modules, seven of which represent the major axis I diagnostic classes. Because of its modular construction, it can by adapted for use in studies in which particular diagnoses (e.g., depression only) are of interest. The output of the SCID is recorded as the presence or absence of each of the disorders being considered, for current episode (past month) and for lifetime occurrence.