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Individual Differences in Vulnerability to Dependence - Coggle Diagram
Individual Differences in
Vulnerability to Dependence
Pre-Existing
Dysregulation
tarter et al (2003 and 2004)
traits of individuals at risk of dependence prior to drug use
"high risk" group initiated drug use at an earlier age compared to "low risk"
age of initiation was predicted by the child's level of emotional and neurobehavioural dysregulation.
suggests that there is a broad spectrum of dysregulated emotional and cognitive traits that predict the early age of drug use onset.
christie et al (1988):
confirmed anxiety and depression as pre-existing risk factors for substance use disorder
depression or anxiety disorders double the risk for developing substance use disorders.
found that four major disorders commonly begin in late adolescence or young adulthood.
mean age of onset for anxiety disorders was found to be around 15.
mean age of onset for major depressive episodes was 24.
mean age of onset for drug abuse/dependence was 19
mean age of onset for alcohol abuse/dependence was 21.
combined estimate: if you develop an anxiety or depressive disorder prior to drug use, you have twice the risk of acquiring drug or alcohol use disorders compared to someone who doesn't have anxiety or depressive disorders.
holds true for men and women.
ersche et al (2010):
examined impulsive traits in drug users and their siblings
drug users had higher impulsivity compared to control groups and sibling groups
sibling group had higher impulsivity compared to controls.
suggests that drug user's impulsivity may have pre-existed their drug use because higher impulsivity is shared with their siblings
nature vs nurture.
barrettes impulsivity scale (BIS): a standardised questionnaire used in cognitive neuroscience research to quantify impulsive traits of participants.
Age of Onset
earlier age of onset is associated with a higher risk of becoming dependent, even when individuals are matched for the same total of years consuming drugs.
early age of onset makes one more sensitive to the dependence-promoting effects of drugs.
dysregulated traits may increase one's risk of dependence by promoting an earlier age of drug use onset.
wong et al (2013)
studied role of age of onset on dependence formation in rats
adolescents showed greater activity in VTA DA neurons
adolescents escalated cocaine self-admin to double the level of adults
supports early age of onset increasing sensitivity to the rewarding effects of drugs which promotes increased use.
although age of onset influences one's propensity for dependence, it does not determine it.
experience and value appear to play a role in promoting one's transition.
Drug Reward
the extent to which the individual experiences the drug effect as rewarding, and this influences the transition from experimentation to dependence.
fergusson et al (2003):
subjective reports of cannabis liking during initial exposure predicted future development of cannabis dependence.
34.1% of those who said they did get really high in early experience became dependent, whereas 12.4% of those who said they did not get really high during initial experience became dependent.
experience of drug reward in early exposure is important for the transition to dependence.
individual differences in experience of drug reward can also be seen at subsequent stages of the drug use career.
Dysregulation and Loss
of Control
dysregulation caused or exacerbated by drug use is associated with an inability to quit using drugs at the end phase of a drug use career.
there is evidence that dysregulation in established drug users is not associated with greater experience of drug reward.
dysregulation in established drug users confers an inability to exert top-down or cognitive control over drug use, presumably because of damage to the brain mechanisms involved in behavioural regulation.
dysregulation in established drug users leads to an inability to exert cognitive control over drug use.
Tiffany's Cognitive Theory
tiffany (1990):
complied studies which reported correlation between craving to use drugs and the amount consumed
"the correlations between self-reported urges and drug use behaviour are not exceptionally strong (p.150)."
drug use is partially governed by desire and partially automatic.
belin et al (2008) and hogarth 2011):
*dysregulation promotes governance of drug use by automatic behavioural routines rather than desire, presumably rendering drug use behaviour less susceptible to self-control (habits over goal-directed actions)
average correlation across all nine coefficients was 0.40, accounting for approximately 16% of variance.
even if only the significant correlations are examined, the average coefficient is 0.5, indicating only 25% shared variance between self-reported urges and actual drug use behaviour.
"drug use behaviour in the addict represents activity-controlled largely by automatic processes, whilst drug use behaviours represent skills that are relatively fast and efficient, stimulus-bound, initiated and completed without intention. difficult to impede, cognitively effortless, and capable of being inactive in the absence of awareness.
Dysregulation and
Quitting
moeller et al 2001):
examined relationship between impulsivity and quit success
HI were 40% more likely to stop attending treatment.
at the end of the study only 30% of HI remained compared to 70% of LI.
it is assumed that individuals who stop attending are likely to have relapsed, providing evidence that impulsivity (dysregulation) is associated with diminished capacity to quit.
aharonovich et al (2003):
examined cognitive function of cocaine-dependent individuals in a treatment program.
low scores on the cognitive assessment had 20% higher likelihood of terminating treatment compared to high scorers.
15 week period
had no comorbid diagnosis of mood disorders, anxiety disorders, psychosis, adhd, seizures, head injuries, or learning disabilities.
baseline: assessed for cognitive functioning using a computer-based microcog called assessment of cognitive functioning.
evaluates attention, mental control, memory, spatial processing, reasoning, information processing accuracy > cognitive functioning and cognitive proficiency.
those who scored low had a higher likelihood of terminating attendance at treatment overall (20%).
impulsivity not measured.
lasser et al (2000):
rates of self-reported current smoking and rates of quitting over individuals lifetime
22.5% with no mental illness currently smoked and 42.5% had quit.
respondents with a mental illness were more likely to currently smoke and showed less ability to quit.
psychosis showed a zero rate of quitting, although the other mental illnesses were fairly uniform in quit rates compared to the group with no mental illness.
three phases of individual differences in vulnerability to dependence:
pre-existing dysregulated traits is associated with early onset of drug use.
transition from experimentation to stable use is promoted jointly by earlier age of onset and by individual differences in the experience of drug reward value
at the end of the drug use career, experience of greater drug reward produces an inability to quit and dysregulated traits caused or exacerbated by drug use combine and are associated with an increased inability to quit drugs due to loss of cognitive control