Never Enough: the neuroscience and experience of addiction (The Addicted Brain)

by Judith Grisel

After about thirty years of highly motivated focus on the research, I’d say there are four primary reasons people like me develop addictions. Well, actually five, but I’m saving the gloomy news for last. The four are these: an inherited biological disposition, copious drug exposure, particularly during adolescence, and a catalyzing environment. It’s not necessary to have all four, but once some threshold is reached, it’s like breaching a dam—virtually impossible to rebuild. So, with enough exposure to any addictive drug, any one of us will develop the hallmarks of addiction: tolerance, dependence, and craving. But if the biological predisposition is very high, or use starts during adolescence, or certain risk factors are present, less exposure will do the trick.