summary Several screening, diagnostic and assessment instruments can provide valuable guidance for the treatment of addictive disorders. In screening for alcohol problems we recommend the regular use of the Alcohol Use Disorders Identification Test (AUDIT) or München Alcoholism Test (MALT(-3)). The European Addiction Severity Index (EuropaSI) and the Readiness to Change Questionnaire, Dutch Translation (RCQ-D) can give important indications with regard to the effect of treatment programmes. New instruments are to be developed for dual diagnosis patients and adolescent populations.