Guiding Questions – Learning Goals
What is addiction?
Addiction – has several defining components – including:
1. Continued engagement in a behavior despite adverse consequences
2. Diminished self-control over engagement in the behavior
3. Compulsive engagement in the behavior
4. An appetitive urge – or craving state – prior to engaging in the behavior
Addiction is the result of when the brain’s approach mechanism is hypersensitized
How do you become addicted (tolerance, abstinence, craving)?
Learning Theory of Addiction
Addictive behavior – as something that is learned and can be un-learned
1. Learning theory – suggests behavior can be understood by examining the
rewards and punishments that people experience in response to things they do
2. Social learning theory – focus mostly on environmental causes of behavior –
to include intraindividual factors
Operant Conditioning – the process by which various rewards and punishments increase or
decrease the likelihood of individual repeating some action in the future
- Positive reinforcement – activates the reward pathways
- Negative reinforcement – comes in the form of withdrawal – the removal of
this negative state increases likelihood of engaging in substance use again in future
Contiguity – helps understand why strong punishments associated with addiction often fail to
stop the behavior from recurring
Classical Conditioning – stimuli frequently paired together form associations in the brain
, 1. Drug opposite conditioned responses – include conditioned withdrawal and
conditioned tolerance
- Conditioned withdrawal – if drug-opposite CRs occur before a dose is
received – they subtract from the drug effect – resulting in attenuation of drug effects
- Conditioned tolerance – the attenuation of drug effects commonly seen with
repeated administration under similar circumstances of the same dose of drug
- These CRs can also produce relapse in abstinent people due to producing
craving when exposed to drug-related cues
Social Learning Theory
Social learning can occur via the observation of others – i.e., modeling
1. We are able to learn about the outcomes of a particular behavior by observing
others
Neurocognitive Perspective
Addictions understood in terms of a certain imbalance between Impulsive/Reflexive and
Reflective decision-making
1. The Reflective System – dependent on cognitive inhibitory control and
delayed gratification
- The system behind the capacity to resist craving and make adaptive decisions
2. The Reflexive System – i.e., those processes linked to impulsivity and risky
behaviors
- The system behind all of the automatic motivational and emotional responses
to reward – yielding faster approach action tendency
Impulsivity can be differentiated into Impulsive Choice – of a smaller and more immediate
reward over a delayed one – and Impulsive Action – stemming from inability to stop a
dominant behavior
- Both may be due to reward-seeking or poor inhibitory control
Compulsive substance seeking combined with a neglect of controlled decision-making in
AUDs – explained by means of deficits within both reflective and reflexive systems
, Socio-Environmental Approach
Implicates social and environmental cues – and certain individual sensitivity to them – as
involved in the development of AUDs and the processes of recovery and maintenance of
abstinence
Substance-related settings and social interactions may trigger craving and relapse
The vulnerability to alcohol-related cues together with the anticipation of reward
- Translate into a neural response in the form of reward pathway activation
SUDs and AUDs reflect pathology of neuroplasticity
- Socio-environmental cues provoke behavioral and neurobiological responses
Withdrawal and Tolerance
The process of homeostasis ensures that the brain is constantly adapting and changing in order to
remain in balance
1. Drugs of dependence upset the balance – as a result the brain will adapt to
minimize the effect of the drug and restore normal function
2. If drug is used frequently – the brain will adapt to be in balance while the drug
is present
- If we stop taking the drug – brain is no longer in balance – resulting in
tolerance and physical dependence
Tolerance
When a drug is repeatedly taken and its effects diminish over time – to achieve original
intensity, a larger dose may be needed
1. Tolerance does not develop to all drug effects with the same speed or to same
extent
2. Tolerance is often developed to the more unpleasant effects first
3. Cross-tolerance – tolerance developed to one drug will also develop to all
drugs in that same class
Cellular Tolerance
,It occurs as a consequence of changes in the number of receptors, the function of the
receptors, and/or alterations to the responsiveness of post-synaptic neurons
- Represents the brain’s attempt to seek normality by activation of homeostatic
mechanisms
Withdrawal Syndrome
It provides a source of motivation – via negative reinforcement – for one to keep using as a
way to remove the discomfort
The severity and duration of the withdrawal syndrome are determined by:
1. Patterns of Drug Use – one needs a sufficient amount of drug in the body for a
long period of time in order to develop physical dependence
2. Dose of Drug Consumed – the greater the amount of drug that is usually
consumed, the more severe the withdrawal and the higher the degree of physical
dependence
3. Length of Time – the longer one has been using, the more intense the
withdrawal
4. Nature of the Drug Itself – the longer a single dose of drug produces an effect,
the less intense the withdrawal, but the longer its duration
- Drug Half-Life – the intensity of withdrawal is inversely related to the half-life
of drug; the duration of withdrawal is directly related to the half-life of drug
Withdrawal represents the unopposed consequence of the adaptation in the CNS to the
presence of the drug – key characteristics of tolerance and the withdrawal syndrome include:
1. If tolerance is developed to one drug – it will extend to all other drugs in that
class
2. The concentration of the drug in the brain and the duration of its presence –
will affect the extent and rate of tolerance and neuroadaptation
- The higher the usual dose of the drug and the shorter the half-life – the more
intense the withdrawal
, - A drug with a longer half-life – will lead to less severe withdrawal but
experienced for much longer
What are predictors of addiction?
The single best predictor of substance use – is the proportion of substance-using friends
- As well as parenting domains – e.g., parental monitoring and permissiveness –
as well as parental perceptions and attitudes toward substances
- As well as sibling influences
Temperamental traits such as high novelty seeking and low harm avoidance as well as indices
of externalizing behavior
Additionally, expectancies about the effects of substances, reasons for not using, and school
achievement
How does it progress? Once an addict, always an addict?
Remission without treatment is the norm – so no, once an addict, not always an addict
Which addictions are most common? Who is most at risk of becoming addicted?
There are several cognitive and neural features that make youth more predisposed to
engaging in heavy alcohol and marijuana use during adolescence:
1. Impulse Control/Inhibition – key cognitive feature involved in regulating
substance use; predisposes youth to initiate substance use
- Compromised functioning during early adolescence prior to onset of substance
use – related to subsequent substance use by age 18
2. Frontal and Parietal Areas – less brain activation predictive of greater
substance involvement by late adolescence
3. Reward Processing – higher brain activation during reward processing is
predictive of greater substance use later on
, 4. Less volume in brain regions involved in impulsivity, reward sensitivity, and
decision-making – influence the initiation of substance use
- E.g., orbitofrontal cortex, frontal gray matter, cerebellar white matter, nucleus
accumbens, anterior cingulate, white matter integrity
Predisposing Neural Factors
1. Developmental increases in the connectivity of the salience and reinforcement
learning networks – and the resulting heightened emotional arousal, reward
sensitivity, and value of social information
- Elevate the valiance and rewarding effects of substance use and associated
cues
2. Behavioral control and functioning of the executive network in the context of
– high affect, intense emotion, and highly salient rewards – including strongly valent
social situations – are still developing
3. The surge in the need to belong, attunement to overt and implicit peer
feedback and behavior, and development of the social cognition network
- May increase willingness to use in order to fit in, be accepted by, or share a
social experience with peer group
4. Enhanced neural plasticity in the form of associative learning may further
drive formation and strengthening of associations between substance use and the
rewarding social outcomes
- Which may reciprocally reinforce and increase likelihood of substance use in
peer contexts
Predisposing Personality Factors
Traits that predispose people to substance dependence:
1. Novelty seeking – the extent to which individuals try to engage in new
experiences
2. Harm avoidance – the extent to which one worries and is pessimistic
, 3. Reward dependence – one’s tendency to learn quickly from rewarding
behaviors and the extent to which they will repeat rewarding behaviors in the future
4. Sensation seeking – predicts engagement in addictive behaviors – important in
the early stages of development of addictions
- Display behavioral disinhibition and high susceptibility to boredom
Is addiction mostly determined by genetic or by environmental factors?
The emergence of substance abuse results from complex interactions between both genetic
and environmental influences
- The interplay of these influences may vary for different substance use
outcomes and at different points in development
Heritability increases in environments with greater substance availability and exposure
- Heritability appears stronger for problematic use than for initiation of use
The Substance Use Effects Pathway – individual differences in sensitivity to the effects of
particular substances create differential vulnerability to the development of SUDs
The Deviance Proneness Model – parents with SUDs both genetically transmit
predispositions to behavioral ‘under-control’ and provide suboptimal parenting setting the
stage for substance use
The Stress and Negative Affect Pathway – parents with SUDs may genetically transmit
predispositions for high negative emotionality and poor emotion regulation
1. And provide an environment that is high in stress – leading to HPA axis
dysregulation – and poor development of appropriate coping
- Risk of abusing substances as a way to cope with stress and negative affect
How can the genetic factors of addiction be studied?
Genetic factors can be studies using longitudinal twin studies and adoption studies
