Morphometric Biomarkers of Addiction and Treatment Response

Abstract

The monumental problem of addiction raises a question: Why do some people who initially experiment with mind-altering substances become addicted while others do not? In a large epidemiological survey it was reported that 23 percent of individuals who try heroin become dependent, while 17 percent, 15 percent, and 9 percent of individuals who try cocaine, alcohol, and marijuana become dependent. And 32 percent of individuals who try tobacco become addicted (Anthony & Petronis, 1995). To complicate the problem of addiction further, treatment strategies are effective only for some individuals. For example, varenicline (Chantix™) is the most effective first-line medication for nicotine dependence, but treatment trials demonstrate that less than half of individuals who receive varenicline treatment derive benefit (Reus et al., 2007). A third complication stems directly from the definition of the disease itself. The National Institute on Drug Abuse (NIDA) defines addiction as ‘a chronic, relapsing disease characterized by compulsive drug seeking and use despite harmful consequences, as well as neurochemical and molecular changes in the brain’ (http://www.drugabuse.gov). Thus, an individual may remain abstinent for months or even years and subsequently succumb to the cardinal feature of substance use disorders (SUDs) highlighted by NIDA’s definition of addiction: relapse.