Risk behavior and addiction in adolescence
Articles lecture 1: Introduction ‘risk behavior and addiction in adolescence’
Addiction, adolescence, and the integration of control and motivation, Gladwin et al. (2011)
The likelihood of initiating addictive behaviors is higher during adolescence than during any other
developmental period. The differential developmental trajectories of brain regions involved in
motivation and control processes may lead to adolescents’ increased risk taking in general, which
may be exacerbated by the neural consequences of drug use. Neuroimaging studies suggest that
increased risk-taking behavior in adolescence is related to an imbalance between prefrontal cortical
regions, associated with executive functions, and subcortical brain regions related to affect and
motivation. Dual-process models of addictive behaviors are similarly concerned with difficulties in
controlling abnormally strong motivational processes. We acknowledge concerns raised about dual-
process models, but argue that they can be addressed by carefully considering levels of description:
motivational processes and top-down biasing can be understood as intertwined, co-developing
components of more versus less reflective states of processing. We illustrate this with a model that
further emphasizes temporal dynamics. Finally, behavioral interventions for addiction are discussed.
Insights in the development of control and motivation may help to better understand – and more
efficiently intervene in – vulnerabilities involving control and motivation.
Introduction
In this review, we will focus on symmetries between adolescence- and addiction-related changes in
motivation and cognitive control that may help explain increased the likelihood of substance abuse
and the onset of addiction in adolescence. During adolescence, children increasingly master the
ability to control their behavior for the benefit of longer-term goals. These advances in self-
regulation abilities in adolescence, however, are accompanied by pronounced changes in
motivational processes. These can have profound consequences for health in adolescence, as the
imbalance between relatively strong affective processes and still immature regulatory skills might
contribute to the onset of developmental disorders.
Risky decision making in adolescence
Typically, the occurrence of risk-taking behavior follow an inverted U-shape pattern across
development, being relatively low in childhood, increasing and peaking in adolescence and young
adulthood, and declining again thereafter.
Neural developments underlying risky decision making
Insights from anatomical and functional changes in the rodent and the human brain have led to
neurobiological models characterizing the “adolescent brain” by two interacting systems. The first is
the relatively early maturing and “hot” affective-motivational bottom-up system (representation of
rewards) and the second is the more slowly developing “cold” top-down control system (self-control,
planning, abstract thinking, working memory, and goal-directed behavior, for example enabling the
individual to resist short-term temptations in exchange for longer-term benefits).
The hypothesis that these brain systems develop at a different pace during childhood and
adolescence and into young adulthood has received support from anatomical brain development
studies. Human functional neuroimaging studies have supported the notion that subcortical brain
regions and networks implicated in “bottom-up” affective-motivational processes – such as
processing of rewards and approach motivation – mature around the onset of puberty and early
adolescence. In contrast, cortical brain regions important for “top-down” control mature later in
,development, and more gradually into young adulthood. There is evidence that it might be
particularly difficult for adolescents (compared to children and adults) to inhibit approach behavior in
the presence of appetitive salient cues. In adolescence individuals are more likely to take risks than in
adulthood, and therefore especially in this phase of life, it is important to understand the triggers
that may cause some adolescents to take unhealthy risks, such as in the case of addiction.
Addiction
Drug use is an example of risky behavior that is of particular concern in adolescence. Current
neurobiological research has identified two broad types of neuro-adaptations that result from
repeated alcohol and drug use. Both seem likely to interact with normal developmental risk factors
of adolescence. There is a robust association between age of onset and risk for subsequent alcohol
and drug problems, and between heavy adolescent drinking and later alcohol problems.
First, neural sensitization leads to strong impulsive reactions to classically conditioned cues that
signal alcohol or drugs, and there is evidence that this occurs more rapidly during adolescence. In
later phases of addiction, habitual responses become important, with cues automatically triggering
approach-reactions, outside voluntary control. In addition, there is evidence that new initiation of
drug use may be triggered by negative affect, which is then temporarily relieved. Such negative
reinforcement processes are associated with severe drug dependence. Note that all of these neuro-
adaptations have the effect of gradually decreasing voluntary control over substance use.
Second, there is evidence that heavy alcohol and drug use results in impaired control functions,
especially when heavy use takes place during adolescence.
In summary, while most adolescents experiment with at least some addictive substances, only few
of them become addicted. This highlights the importance of better understanding individual
differences, especially in development, that form risk or protective factors for addiction.
Dual-process models of addiction
The literature on adolescent risk-taking and addiction converges on the idea of dual processes, i.e.,
the existence of two qualitatively different types of process that underlie and may compete for
control of behavior. In both adolescence and addiction, the literature suggests that risky behavior
results from an inability of reflective processes to sufficiently modulate the effects of impulsive
processes.
Interventions
A number of novel interventions have recently been developed with attempt to influence the
neurocognitive processes in addiction.
Working memory training
The first type of intervention is aimed at training the likelihood of successful control. Working
memory training has recently also been used successfully in addiction, where it was found that it
helped problem drinkers with strong positive memory associations for alcohol, presumably because
it helped them to overcome the bias to approach alcohol, driven by these associations.
Cognitive bias modification
In addition to studies aimed at increasing the likelihood of successful controlled processing, research
has focused on the development of novel interventions, termed cognitive bias modification (CBM),
aimed at modulating biases that could underlie failures of controlled processing, including attentional
biases (AB), approach biases, and evaluative memory-biases.
Attentional bias modification
,It suggests an increase in the ability to disengage from, or to discontinue the reprocessing of,
threatening information.
Approach bias modification
Recently, another cognitive bias in addiction has been addressed with re-training: an approach-bias
for substance-related stimuli.
Further developments in intervention
One important issue, which is especially important in the context of adolescent addiction problems,
is motivation to participate in a training (or more generally in any intervention). First, most
adolescents with substance use problems do not believe they have a problem. Second, should they
recognize that they have a problem, they have to be convinced that it makes sense to do the training.
Conclusion
The literature on adolescence dovetails with that on addiction, both in terms of the theoretical bases
– imbalances are proposed that can be broadly described in terms of dual processes – but also in
terms of likely substantial interactions: the vulnerabilities of adolescents map onto what makes
addictive substances harmful. In practical terms, dual-process models of addiction not only provide
hypotheses why adolescents are at increased risk of substance abuse, but have also suggested
interventions that have already been successfully applied in adults.
Beautiful brains. Moody, impulsive, maddening. Why do teenagers act the way they do? Viewed
through the eyes of evolution, their most exasperating traits may be the key to success as adults,
Dobbs (2011).
Our brains take much longer to develop than we initially had thought. This suggests both a simplistic
unflattering explanation for teen’s maddening behavior – and a more complex, affirmative
explanation as well.
The first full series of scans of the developing adolescent brain showed that our brains undergo a
massive reorganization between our 12th and 25th years. The brain doesn’t actually grow very much
during this period. But as we move through adolescence, the brain undergoes extensive remodeling,
resembling a network and wiring upgrade.
For starters the brain’s axons’ transmission speeds up to a hundred times. At the same time the most
heavily used synapses grow richer and stronger and the synapses that see little use begin to wither.
This synaptic pruning causes the brain’s cortex – the outer layer of gray matter where we do much of
our conscious and complicated thinking – to become thinner but more efficient. Taken together,
these changes make the entire brain a much faster and more sophisticated organ.
This process of maturation, once thought to be largely finished by elementary school, continues
throughout adolescence.
When this development proceeds normally, we get better at balancing impulse, desire, goals, self-
interests, rules, ethics and even altruism, generating behavior that is more complex and, sometimes
at least, more sensible. But at times, and especially at first, the brain does this work clumsily. It’s hard
to get all those new cogs to mesh.
Studies help explain why teen behave with such vexing inconsistency. Along with lacking experience
generally, they’re still learning to use their brain’s new networks.
For a while teen brains were seen as ‘work in progresses’. But some researchers began to view it
differently. The resulting account of the adolescent brain – call in the adaptive-adolescent story –
casts the teen less as a rough draft than as an exquisitely sensitive, highly adaptable creature wired
almost perfectly for the job of moving from the safety of home into the complicated world outside.
, This view sits better with biology’s most fundamental principle, that of natural selection. Selection is
hell on dysfunctional traits. If adolescence is essentially a collection of them, then how did those
traits survive selection? They couldn’t – not if they were the period’s most fundamental or
consequential features.
The answer is that those troublesome traits don’t really characterize adolescence.
To see past the distracting, dopey teenager and glimpse the adaptive adolescent within, we should
look not at specific, sometimes startling, behaviors but at the broader traits that underlie those acts.
Let’s start with the teen’s love of the thrill.
Seeking sensation isn’t necessarily impulsive. And although sensation seeking can lead to dangerous
behaviors, it can also generate positive ones: the urge to meet more people, for instance, can create
a wider circle of friends, which generally makes us healthier, happier, safer, and more successful.
A love of novelty leads directly to useful experience.
Also peaking during adolescence is risk-taking.
If teens think as well as adults do and recognize risk just as well, why do they take more chances?
Here, as elsewhere, the problem lies less in what teens lack compared with adults than in what they
have more of. Teens take more risks not because they don’t understand the dangers but because
they weigh risk versus reward differently: in situations where risk can get them something they want,
they value the reward more heavily than adults do.
Teen respond strongly to social rewards. Physiology and evolutionary theory alike offer explanations
for this tendency. Physiologically, adolescence brings a peak in the brain’s sensitivity to dopamine, a
neurotransmitter that appears to prime and fire reward circuits and aids in learning patterns and
making decisions. This helps explain the teen’s quickness of learning and extraordinary receptivity to
reward – and his keen, sometimes melodramatic reaction to success as well as defeat.
The teen brain is similarly attuned to oxytocin, another neural hormone, which (among other things)
makes social connections in particular more rewarding.
This helps explain another trait that marks adolescence: teens prefer the company of those their own
age more than ever before or after.
Yet teens gravitate toward peers for another, more powerful reason: to invest in the future rather
than the past.
This supremely human characteristic makes peer relations not a sideshow but the main show.
Excitement, novelty, risk, the company of peers. These traits may see to add up to nothing more than
doing foolish new stuff with friends. Look deeper, however, and you see that these traits that define
adolescence make us more adaptive, both as individuals and as a species.
Chapter 1: A general introduction to the concept of addiction and addictive effects, Sussman (2017)
Substance and behavioral addictions
Both substance and behavioral (process) addictions describe behavior that results in clinically
significant impairment. Substance addiction pertains to repetitive intake of a drug (such as alcohol) or
of food, whereas behavioral addiction pertains to engaging in types of behaviors repetitively which
are not directly taken into the body such as gambling or sex. Until recently, the scientific community
focused on, or considered seriously, as an “addiction” only misuse of drugs that led to physiological
withdrawal symptoms (the appearance of both physical and psychological symptoms which are
caused by physiological adaptations in the central nervous system and the brain due to chronic
exposure to a substance). In general, researchers considered those objects on which one could
become addicted as being drugs which cross the blood-brain barrier and, as exogenous ligands,
block, facilitate, or mimic endogenous ligand (naturally occurring neurotransmitter) functions.
