A tool that consists of a structured interview to assess for and diagnose a broad spectrum of psychiatric disorders in children. The DISC has been revised on numerous occasions to reflect new research on psychiatric pathology, and to coincide with updates to the DSM and ICD classification systems. Trained, non-clinicians can administer older versions— DISC-I, DISC-R, DISC-2.1, and DISC-2.3—as well as the newest version—DISC-IV. All versions contain two different forms, DISC-Y, for administration to children aged 9 to 17 years; and DISC-P, for administration to parents and/or caretakers of children aged 6 to 17 years. The DISC-P contains a few more questions than the DISC-Y; otherwise, the two forms are similar in composition. The original version of the tool, DISC-I, followed DSM-III criteria and focused largely on environmental (i.e. school and home), rather than pathological, domains. The subsequent version, DISC-R, minimized the use of open-ended questions and disorders requiring observations for diagnoses, and added a section to chart time. Shortly after, the DISC-2.1 was introduced, which included more robust psychometrics—assessments of treatment history, age at initial onset of symptoms, and impairments precipitated by a current episode. This was followed by the DISC-2.3, which reduced the length and complexity of questions, and permitted diagnoses of disorders based on symptom criteria. The latest version, DISC-IV, follows DSM-IV and ICD-10 criteria, contains over 30 psychiatric diagnoses commonly seen in youth, allows for information discrimination of initial and present onset of symptoms, inquires about impairments related to symptoms and/or disorders, uses more concisely-worded questions, and has all but eliminated open-ended questions. Answer responses to the DISC-IV are: Yes, No, Somewhat, and Sometimes. The questionnaire is arranged into different modules, which query demographic information, as well as information specific to various disorders—Anxiety, Mood, Disruptive, Substance use, Schizophrenia, and Miscellaneous disorders. The DISC-IV consists of 2,930 items (some of which are asked of all respondents and others only asked of respondents who provide clinically significant responses), and takes about 70 minutes to administer to parents/caregivers, and 90 to 120 minutes to administer to children.