Brain specimens from a large population of predominant heroin abusers were also studied. These specimens, including control samples, were collected at the Department of Forensic Medicine at Semmelweis University, Hungary, as well as from the National Institute of Forensic Medicine, Karolinska Institutet, Stockholm, Sweden. The specimens were collected under the guidelines approved by the local Human Ethical Committees. The demographics and general characteristics for control (n = 15) and heroin (n = 29) subjects (Study II) are described in Table 2 and Supplement 1.
