Lecture 1: An introduction to risk behavior and the development of substance
and behavioral addictions during adolescence
Risk behavior: behavior that poses a risk to a healthy physical, cognitive, psychosocial development
of adolescents (; addiction).
How we review risk behavior → (1) characteristics of the particular substance or behavior,
(2) cultural and societal norms, and (3) scientific knowledge.
Developments during adolescence:
→ Early adolescence (10-13) is characterized by physical growth, sexual maturation, psychosocial
development, and social identity formation.
→ Mid adolescence (14-18) is characterized by experimenting with (risk) behaviors, and personal
identity formation.
→ Late adolescence (19-24) is characterized by practicing adult roles.
Neurological development
Growth in brain volume (; High plasticity of the brain).
● White matter increases (connections): improves communication between brain regions → The
long- term memory increases and the capacity for abstract thinking/metacognition increases.
● Grey matter decreases (nerve cells): pruning, frontal grey matter peaks around puberty.
Factors in adolescence for the peak in risk behavior:
The speed of two brain regions differs:
1) Affective-motivational system (emotional brain) → develops fast
→ Nucleus accumbens (reward center, affective-motivational system, emotions).
The reward center is overactive in early and mid-adolescence.
Experience stronger positive emotions when receiving or anticipating a reward.
+ Enhanced by testosterone
2) Control system (rational brain) → Develops slowly
→ Prefrontale cortex (control system, rational brain).
The rational brain plays an important role in the development of executive functions.
Risk estimation, monitoring long-term goals, inhibits the tendency to respond to (short-term)
possibilities for rewards (; impulse control, behavioral inhibition, and self-control)
Maturation imbalance model: Imbalance between motivational bottom-up versus controlling
top-down processes = increase risk behavior.
(; high reward sensitivity and immature impulse control)
,Psycho-active substances (drugs)
Psycho-active substance: chemicals that cross blood-brain barrier and affect functioning of the
central nervous system.
→ Altering perception, mood or consciousness, and induce cravings after use and loss of control
after being used regularly.
Two ways to define addiction
1) Intentional addiction: describes a causal addiction process.
2) Extensional addiction: classification of characteristics of an addiction.
DSM-5 substance use definition: Use over the last 12 months, meeting at least two of the following
criteria. (1) Loss of control, (2) Social and other impairments, (3) Continuation despite knowledge of
risky use, (4) Pharmacological effects (tolerance and withdrawal).
Two learning principles
Positive reinforcement: rate of behavior increases, because a desirable event results from the
behavior (; euphoria, relaxing).
Negative reinforcement: rate of behavior increases, because an aversive event is prevented for
happening (; prevention withdrawal symptoms).
Sensitivity of the brain reward system decreases, because:
1) reduction in dopamine receptors
2) existing dopamine receptors become less sensitive to dopamine.
→ Result:
1) Tolerance (; needing a higher dose of the drug to have the same effect)
2) Withdrawal symptoms (; during abstinence)
3) A reduced sensitivity to natural incentives (; e.g. reduced sexual interest)
Associative learning
● Repeated use of drugs is having rewarding outcomes (; positive reinforcement)
● Stimuli related to drug use (drug-cues) get associated with its’ rewarding outcome
● Drug-cues itself become salient (“opvallend”) because of its’ association with reward
(; Incentive salience)
Developing (implicit) cognitive bias
Attention bias: addicts develop a heightened attention
towards drug-cues (; seeing it).
Approach bias: addicts develop an automatic tendency to
approach, rather than avoid, drug-cues.
Addiction means an imbalance between the affective
motivational system and control system.
, Dual process models
1) Automatic and impulsive (; motivation)
Subcortical: effectief leren, beloning, bekendheid.
2) Reflective and controlled (; control)
Fronto parietal: uitvoerende controle, doelgericht gedrag, geremdheid, aandacht.
→ Reciprocal connections between the motivation and control part of the brain.
→ Drug cues affect motivation and addiction leads to losing control.
Lecture 2: Individual vulnerability to risk behavior and addiction
Important theories for development of addiction
1) Classical conditioning (Pavlov): certain situations or environments are associated with
engagement in risk behavior. (; unconditioned stimulus “USC” and unconditioned response
“UR” are paired, which result in a conditioned stimulus “CS”.
2) The law of effect (Thorndike): risky behavior will be repeated when the consequence is
beneficial (in the same situation, under the same conditions).
3) Operant conditioning (Skinner): takes place when behavior is changed according to the
consequences by reinforcement and punishment.
▪ Positive reinforcement: adds something good to a situation (e.g. chocolate).
▪ Negative reinforcement: removes something bad from the situation (e.g. no homework).
▪ Positive punishment: something bad is added to the situation (e.g. spraying water).
▪ Negative punishment: something good is removed from the situation (e.g. no dessert).
4) Social learning/ modeling (Bandura): combination of behavior and cognition, learning from
observing others.
Individual differences
1) Genetic vulnerability: presence of genetic factors, genotype. Environment can trigger this
genotype (; diathesis-stress model). Substance can change the expression of genes.
2) Personality as vulnerability: has two domains
● Disinhibited domain: consist of impulsivity and sensation seeking.
> Impulsivity is the lack of cognitive control over behavior (; acting without thinking,
impatience / delay of gratification, inability to regulate responses).
> Sensation seeking is the need to look for challenges and incentives while taking
risks (; also known as novelty seeking). This overlaps with impulsivity (drive for
exploration).
Prefrontal cortex; which is responsible for impulse control, develops until late
adolescence.
Limbic system / amygdala; which is the rewarding system, is already matured.
→ There is an imbalance between impulse control and the reward system, poor
control shows association with more drug use.
