Explain the similarities and differences between addiction to chemical substances and addiction to gambling. Discuss the rationale for moving the diagnosis of pathological gambling (which was renamed gambling disorder in DSM-5), from the Impulse Control Disorders category in DSM-IV-TR to the Substance-Related and Addictive Disorders category in DSM-5. You may find the DSM-5 development web site (APA, 2013) very helpful, particularly the information found under the Research Background tab.