The CIDI is a comprehensive, standardized instrument for assessment of mental disorders according to the definitions and criteria of ICD-10 and DSM-IV. It is intended for use in epidemiological and cross-cultural studies as well as for clinical and research purposes. It enables simultaneous comparisons of diagnostic systems in epidemiological studies. The CIDI core Version 2.1 (1998) covers all major diagnostic disorders. The substance abuse disorders covered are alcohol, tobacco, and nine categories of illicit drugs. Each module, including the alcohol module, serves the diagnostic criteria of DSM-IV and ICD-10. The standard version determines whether the alcohol disorders were ever present and whether they were present in the last year, the last 6 months, the last month, and the last 2 weeks. There is also a 12-month version that does not assess disorders prior to a year earlier. In addition to determining whether official criteria for Alcohol Dependence, Alcohol Abuse, Harmful Use, and Alcohol Withdrawal are met, the alcohol module dates the age of first use of alcohol and the age at first and last symptom. The CIDI is useful in clinical settings because it produces scores for a positive diagnosis for alcohol dependence, alcohol abuse, and alcohol withdrawal. It also provides a count of total alcohol symptoms in the lifetime, clustering of symptoms in a single 12-month period, age at first problem related to alcohol, age at recovery, current drinking level, heaviest drinking level ever, impairment due to drinking, and comorbid mental disorders. It is designed for epidemiological use. The CIDI-Core contains 20 major questions and 59 subquestions and takes approximately 75 minutes to administer. In a study comparing 5 diagnostic instruments (SCID, CIDI-2, DIS-IV, DSM-IV Checklist, SDSS) for suitability for use in the CTN Clinical Trials Network, the CIDI-2 was ranked 2nd (Forman et al 2004). This instrument was revised in 1998 and renamed the WMH-CIDI (World Mental Health CIDI). Read more about this version and how it differs from version 2.1 at the