For more than 11 years, the American Psychiatric Association (APA) has been laboring to revise the current version of its best-selling guidebook, the Diagnostic and Statistical Manual of Mental Disorders (DSM) (see "Psychiatry's Bible Gets an Overhaul” in Scientific American MIND). Although the DSM is often called the bible of psychiatry, it is not sacred scripture to all clinicians—many regard it more as a helpful corollary to their own expertise. Still, insurance companies in the U.S. often require an official DSM diagnosis before they help cover the costs of medication or therapy, and researchers find it easier to get funding if they are studying a disorder officially recognized by the manual. This past December the APA announced that it has completed the lengthy revision process and will publish the new edition—the DSM-5—in May 2013, after some last (presumably minor) rounds of editing and proofreading. Below are the APA's final decisions about some of the most controversial new disorders as well as hotly debated changes to existing ones, including a few surprises not anticipated by close observers of the revision process:
Hoarding is now an official disorder
Hoarding is the excessive accumulation of stuff—often stuff that most people would throw out or give away, such as junk mail, unworn clothes, old newspapers and broken tchotchkes. Some people hoard animals or obsessively collect a particular item, such as fabric. Many hoarders store their collections in their homes, but some use their cars or offices instead. Although the stuff piles up, commandeering all living spaces save for narrow "goat trails," hoarders refuse to get rid of anything. In some cases, hoarders simply do not recognize all the chaos and clutter as a problem. In past editions, the DSM regarded hoarding as a symptom of obsessive-compulsive disorder (OCD). Now, in a move well supported by a variety of research, the DSM-5 makes hoarding a disorder in its own right.
Studies published in the last 10 years have emphasized that many hoarders do not have any other symptoms of OCD and that hoarding may be more common than OCD in the general population. Investigations have also suggested that although OCD and hoarding can co-occur, they are genetically and neurologically distinct. Parents and siblings of hoarders show higher rates of hoarding than do first-degree relatives of people with OCD, for instance, and hoarding seems to be inherited as a recessive trait, whereas the compulsive checking and organizing that characterizes OCD is dominant. Further, although some antidepressants, such selective serotonin reuptake inhibitors (SSRIs), and cognitive behavioral therapy often help OCD, their success is much more mixed in changing hoarding behaviors.
Neuroimaging studies support the new diagnosis as well. They have revealed that when hoarders make decisions about what to keep and what to throw out, their brain activity is markedly different from that of people with OCD and people without a mental disorder. In such situations, hoarders take far longer to make up their minds and show more activity in the anterior cingulate cortex, a brain region that is important for decision-making, as well as higher activity in the insula, an area of the brain that helps us interpret our emotions and physiological responses. Hoarders, it seems, form strong emotional attachments to objects that most people would not hesitate to chuck out.
Renaming addiction and introducing gambling disorder
The DSM has long avoided the word “addiction.” Instead, the DSM-IV—the current edition and predecessor of the new manual—discusses substance abuse and substance dependence. According to the fourth edition, substance abuse refers to repeated drug use that creates problems at work or school and in one's social life—binge drinking in college, for example. In contrast, the DSM-IV's definition of substance dependence is what the phrase "drug addiction" brings to most people's minds: an inordinate amount of time spent acquiring a drug, increased tolerance, recurrent physical or psychological harm as a result of drug use, failed attempts to stop taking the drug and symptoms of withdrawal.