NEUROETHICS / SESSION 12
Models of
addiction
addiction
What each model explains.
What each still owes us.
12
THE EXPLANATORY TASK
Continued use despite severe costs
The same pattern.
Different explanatory questions.
Different explanatory questions.
Brain disease
Which neural functions
have gone wrong?
Social model
Which circumstances
sustain use?
Psychology first
What does the person
expect from using?
THE BRAIN DISEASE MODEL
Three claims that can come apart
Disease
Is there a dysfunction?
Brain
Does brain pathology
explain the condition?
Compulsion
How much control
does the person retain?
One label can conceal several commitments.
An objection to one claim may leave the others intact.
BRAIN MODEL / ARGUMENT 1
The objection to irresistible compulsion
Deductive argument against a strong version
- 1If addiction makes drug use irresistible on every occasion, people with addiction cannot deliberately refrain.
- 2People with addiction sometimes deliberately refrain when the available alternatives change.
CAddiction does not make drug use irresistible on every occasion.
WHAT THE COUNTEREXAMPLE SHOWS
An available choice can still be hard
A deliberate refusal
Evidence of control
in those circumstances
in those circumstances
Still to establish
How difficult was it?
How reliable is that control?
BRAIN MODEL / ARGUMENT 2
Brain change does not establish dysfunction
An objection to the evidence for disease
- 1A brain disease explanation requires a relevant brain dysfunction.
- 2Learning and adaptation also change the brain, so change or atypicality alone does not establish dysfunction.
- 3An inference from brain differences to brain disease therefore needs an independent account of what has malfunctioned.
CEvidence of brain differences alone does not establish a brain disease explanation.
WHAT COUNTS AS DISEASE?
Commonness and function
STATISTICAL FREQUENCY
FUNCTIONAL STATUS
Common
Uncommon
Function intact
Dysfunction
Tooth decay
Exceptional athletic ability
Frequency alone cannot locate a condition on the functional axis.
BRAIN MODEL / ARGUMENT 3
Association does not establish causal priority
An objection to an inference from imaging
- 1A primary brain pathology explanation needs evidence that the pathology helps cause continued use.
- 2A brain difference associated with addiction may precede use, result from use, or reflect other causes.
- 3The association alone does not distinguish those possibilities or establish their relative importance.
CAn imaging association alone cannot establish brain pathology as the primary explanation.
Causal mechanisms and intervention evidence can answer this objection. The generalization across cases still needs support.
CAUSATION ACROSS LEVELS
One intervention can change several levels
Available
alternatives
alternatives
Expectations
and motives
and motives
Neural processes
and learning
and learning
Continued
use
use
Social changes can alter several mechanisms.
Neural mediation does not remove the social cause.
Use can also reshape a person’s circumstances.
THE STRONGEST DISEASE REPLY
Impaired choice can coexist with choice
01
Disease can impair a capacity without abolishing it.
02
A brain disorder can respond to changes in its environment.
03
The remaining burden is evidence for dysfunction, causal role, and scope.
THE SOCIAL MODEL
The alternatives available to a person
An option on paper
An effective alternative
Can the person obtain it?
Is it valuable and reliable enough?
Social arrangements affect the answers.
Causal influence / Explanatory priority / Sufficiency
SOCIAL MODEL / THE CASE FOR
Social conditions can make a causal difference
A causal argument for including social explanation
- 1When changing an available alternative changes drug use, that alternative is a causal factor under those conditions.
- 2Choice studies and incentive interventions show that available alternatives can change drug use.
- 3Social arrangements help determine which alternatives people can actually obtain.
CAn adequate account must include social conditions that shape effective alternatives.
SOCIAL MODEL / THE CASE AGAINST
Social influence does not establish social sufficiency
The target is a sufficient or generally primary social explanation
- 1A sufficient social explanation must account for who continues using and who recovers.
- 2Evidence that alternatives affect use does not by itself explain differences in people's responses.
- 3Those differences may also depend on learning, motives, withdrawal, or other individual factors.
CThe evidence for social influence alone does not establish a sufficient or generally primary social model.
The social model survives as a causal account. Its strongest version still needs comparative evidence.
PICKARD’S PSYCHOLOGY-FIRST MODEL
What does continued use do for this person?
Continued
use
use
Expected benefit
Relief? Enjoyment?
Place in a life
Belonging? Identity?
A starting point that other evidence can supplement or replace.
PSYCHOLOGY FIRST / THE STRONGEST CHALLENGE
An intelligible story still needs a causal test
A challenge to explanatory priority, not to taking testimony seriously
- 1Giving a psychological explanation priority requires grounds for preferring it to competing explanations.
- 2An intelligible account of a person's reasons can fit their behavior without establishing those reasons' causal importance.
- 3Intelligibility alone therefore cannot establish that psychological explanation should take priority in a case.
CPsychology first needs independent tests and a basis for deciding when to revise or replace the account.
Pickard’s reply: “first” is a defeasible starting point. The challenge is to make that defeasibility work in practice.
MAY’S ALTERNATIVE
Addiction as a disorder
An argument for a working framework
- 1Addiction varies in severity, causes, and the control people retain.
- 2A useful framework should preserve those differences without requiring total compulsion or one universal pathology.
- 3May's disorder model identifies harmful patterns while leaving their particular causes open.
CThere is reason to use the disorder model as a flexible framework for explanation and care.
Its openness is also its limitation: the label alone cannot tell us which causes or treatments matter most.
THE MODELS AND THEIR LIMITS
What each model still owes us
ModelContributionUnresolved burden
Brain diseaseMechanisms that can impair controlDysfunction, causal role, and scope
SocialCircumstances and effective alternativesIndividual variation and the case for priority
Psychology firstThe person’s motives and point of viewIndependent tests and grounds for revision
May’s disorder modelHarmful patterns with varied causesSpecific causal and treatment guidance
RETURN TO CONTROL AND RESPONSIBILITY
Responsibility depends on the person and the circumstances
Explanatory label
Disease, social condition, or choice
Evidence about the person
Capacities, difficulty, and available alternatives
Ethical judgment
What response is justified? What would help?
READING AND ATTRIBUTION
Sources
Joshua May
Neuroethics: Agency in the Age of Brain Science
Oxford University Press, 2023. Chapter 5, pp. 119–144.
Hanna Pickard
What Would You Do Alone in a Cage with Nothing but Cocaine? A Philosophy of Addiction
Princeton University Press, 2026. Introduction, chapters 6, 8, and 9.
Markus Heilig and colleagues
Addiction as a brain disease revised: why it still matters, and the need for consilience
Neuropsychopharmacology 46 (2021), 1715–1723. DOI 10.1038/s41386-020-00950-y.