“The Neurobiology of Addiction: Implications for the Voluntary Control of Behavior”
Steven Hyman
“Cognitive and social neuroscience and studies of the pathophysiologic processes underlying neuropsychiatric disorders have begun to probe the mechanisms by which human beings regulate their behavior in conformity with social conventions and in pursuit of chosen goals—and the circumstances under which such “cognitive control” erodes.”
Neuroscience, Addiction, and Agency:
“The resulting ideas call into question folk psychology views on the voluntary control of behavior, that is, for the most part, we regulate our actions based on conscious ‘reasons’.”
“The major justification for demarcating neuroethics from the broader field of bioethics derives from the special status of the brain…which is the causal underpinning of our conscious mental lives and of our behavior. This is not a reductionist claim. The structure and function of the brain is influenced not only by ‘bottom up’ factors such as our genes, but also by top-down factors such as ‘lived experience’.”
The Nature of Neuroscience:
“Neuroscience does not obviate the need for social and psychological level explanations intervening between the levels of cells, synapses and circuits and that of ethical judgments.”
“What neuroscience contributes to ethical discourse is mechanistic insight that constrains our interpretations of psychological observations and that suggests new explanatory frameworks for thought and behavior.”
“The question of whether and to what extent an addicted individual is responsible for his or her actions remains a matter of unsettled debate. One proxy for this question is disagreement as to whether addiction is best conceptualized as a brain disease…as a moral condition…or as some combination of the two.”
Addiction as Disease:
“Current definitions of addiction come from medical texts and thus, not surprisingly favor a disease model. Indeed, addiction looks very like a disease. Addiction has known risk factors (family history, male sex) and typical course and outcome: often a chronic course punctuated by periods of abstinence followed by relapse.”
Addiction and Control:
“Modern definitions of addiction focus squarely on the issue of voluntary control. The current medical consensus is that the central feature of addiction is compulsive drug use despite significant negative consequences. The term compulsion is imprecise, but at a minimum implies diminished ability to control drug use even in the face of factors (e.g., illness, failure in life roles, loss of job, arrest) that should motivate cessation of drug use in a rational agent willing and able to exert control over behavior.”
“Despite somewhat different views of mechanism, all current mainstream formulations agree that addiction diminishes voluntary behavioral conduct. At the same time, none of the current views conceives of the addicted person to be devoid of all voluntary control and thus absolved of all responsibility for self-control.”
The Key Question:
“Short of being harshly coerced, severely psychotic, or significantly demented, what can it mean to say that a person cannot control his or her actions? An alcoholic must obtain money, go to the liquor store or otherwise obtain alcohol.”
Cognitive Control and Addiction:
“Mechanisms of cognitive control support successful completion of goal-directed behaviors by maintaining the goal of representation over time, suppressing distractions, and inhibiting impulsive actions that redirect the organism.”
Addictive Drugs and Trojan Horses:
“Addictive drugs are Trojan horses. Unlike natural rewards, addictive drugs have no nutritional, reproductive, or other survival value. However, all addictive drugs exert pharmacologic effects that cause release of dopamine. Moreover, the effects of addictive drugs on dopamine release are quantitatively greater than that produced by natural rewards under almost all circumstances.”
Addiction as Neurochemical Trans-species Warfare!
“Thus, unlike natural rewards, addictive drugs always signal ‘better than expected’. Neural circuits ‘overlearn’ on an excessive and grossly distorted dopamine signal. Cues that predict drug availability such as persons, places, or certain bodily sensations gain profound incentive salience and the ability to motivate drug seeking.”
“Because of the excessive dopamine signal…drugs become overvalued compared with other goals. Rational goals such as self-care, working, parenting, and obeying the law are devalued. In addition, normal aspects of cognitive control weaken; even if the addicted person wants to ‘cut down’ prepotent cue-initiated drug-seeking responses are extremely difficult to suppress.”
“Mechanisms that evolved to motivate survival behaviors, the pursuit of natural rewards, are usurped by the potent and abnormal dopamine signal produced by addictive drugs.”
The Pressing Issue:
“Views based on cognitive neuroscience and studies of addiction pathogenesis suggest that some apparently voluntary behaviors may not be as freely planned and executed as they first appear. Such cognitive views have not yet penetrated folk psychology and it is premature for these views to have any place in the courtroom. Nonetheless, these cognitive views deserve a place in current ethical discussions of personal responsibility. For many reasons, it may be wise for societies to err on the side of holding addicted individuals responsible for their behavior and to act as if they are capable of exerting more control than perhaps they can; however, if the ideas expressed in this review are right, it should be with a view to rehabilitation of the addicted person and protection of society rather than moral opprobrium.”
Hyman on Neuroscience, Addiction, Retribution, and Rehabilitation
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