Studies (e.g. Lee, Hoffman, and Kim-Cohen et al.) show that the DSM is valid in its diagnoses. Different mental health issues were chosen in the different studies cited here, which reinforces this conclusion. It is likely that symptoms for alcohol abuse, dependence, cocaine abuse, pathological gambling and ADHD are well-established, given that the DSM had many revisions to date. Different research methods such as interviews and questionnaires yield data that, for those with mental health disorders, match the DSM criteria.