Addiction and the Concept of Disorder, Part 2: Is every Mental Disorder a Brain Disorder?

In this two-part analysis, I analyze Marc Lewis’s arguments against the brain-disease view of substance addiction and for a developmental-learning approach that demedicalizes addiction. I focus especially on the question of whether addiction is a medical disorder. In Part 1, I argued that, even if one accepts Lewis’s critique of the brain evidence presented for the brain-disease view, his arguments fail to establish that addiction is not a disorder. Relying on my harmful dysfunction analysis of disorder, I defended the view that addiction is a medical disorder and a brain disorder. In Part 2, I consider some broader philosophical issues raised by Lewis’s arguments: (1) I consider a larger puzzle, at the heart of the neo-Kraepelinian program in contemporary psychiatry, that is raised by Lewis’s argument that addiction is not a disorder because the brain displays no damage but only normal learning: must all mental disorders be brain disorders, or can mental disorders occur in normal brains? I argue that mental disorders can occur in normal brains. (2) I critique Lewis’s response to the evolutionary “novel environment” approach to explaining why addiction is a disorder. (3) Lewis agrees with brain-disease proponents that interpreting addiction as brain disorder relieves addicts of moral censure, but I argue that moral defect and brain disease are not exclusive. (4) Finally, I consider Lewis’s “developmental-learning” account of addiction that encourages positive and empowering narrativizing of addiction, but I argue that the developmental-learning view is vacuous due to use of an overly broad notion of “development.”.