There continues to be a debate on whether addiction is best understood as a brain disease or a moral condition. This debate, which may influence both the stigma attached to addiction and access to treatment, is often motivated by the question of whether and to what extent we can justly hold addicted individuals responsible for their actions. In fact, there is substantial evidence for a disease model, but the disease model per se does not resolve the question of voluntary control. (...) Recent research at the intersection of neuroscience and psychology suggests that addicted individuals have substantial impairments in cognitive control of behavior, but this "loss of control" is not complete or simple. Possible mechanisms and implications are briefly reviewed. (shrink)

Stimulants have been shown to be safe and effective for reduction of the symptoms of attention deficit hyperactivity disorder. Despite much debate, however, there has been little empirical evidence as to whether stimulants affect authenticity and moral agency in children. Singh presents evidence that stimulants do not undercut children's' sense of self and increase their experience of agency. These findings are consistent with laboratory evidence that stimulant drugs in therapeutic doses improve cognitive control over thought and behavior.

Heyman's target article is an analytical tour de force, but it makes too hard a distinction between voluntary and driven behavior. It is more fruitful to think about brain and behavior as shifting, interacting “agents,” represented by multiple neural circuits. This has the virtue of better connecting behavioral analysis with wet neuroscience.