4 Individual differences in risk for addiction

GENETICS AND ADDICTION

PERSONALITY AND ADDICTION

Long History

Pedigree charts, then alcohol seen as moral failing, then psychology further developed where alcohol use across families seen (family studies, adoption studies)

Twin studies

Graph - strong heritability of addiction across these twin studies - 40% - 70% of the variance is accounted for

Heritability not to do with the brain changes that psychoactive substances cause - bc there's heritability of problem gambling (30%-50%)

Multivariate twin analysis

Found there's a big heritable overlap in genetic vulnerability across substances (overlap is .82)

Another study found genetic factors correlations with substances are strong across the board - so there's a general risk for addiction which is inherited

Therefore, the individual who becomes addicted to e.g., 1 drug, is bc of their environment which influences their additive risk

MODELS OF PERSONALITY

Eyesenck's PEN model - the big 3

Reinforcement sensitivity theory (BIS, BAS, FFFS)

Cloninger - differences in neurobiological systems (harm avoidance, novelty seeking, and reward dependence)

Big 5 - OCEAN

Zuckerman - sensation seeking

Personality traits that relate to addiction

Traits where you act without restraint

Impulsivity - broad & narrow

Psychoticism

Antisocial sensation seeking

Traits that are sensitive to reward

Behavioural approach system (BAS)

Reward reactivity

Extraversion

Trait that is both impulsive (in broad sense) and reward sensitive

Sensation seeking

Traits that have negative emotionality

Traits related to Neuroticism

Traits related to Behavioural inhibition (BIS)

Trait anxiety

Depression

Reinforcement Sensitivity Theory

Behavioural Approach System (BAS)

Underpins the affect (hope), behaviour (approach) & cognitive responses (go for it) to reward

Fight Flight Freeze system (FFFS)

Underpins the affect (fear), behaviour (avoidance) & cognitive responses (escape) to punishment

Behavioural Inhibition System (BIS)

Underpins the affect (anxiety), behaviour (assess the risks) & cognitive responses (be careful) to conflict

BAS system - which is in the brain reward pathway - leads to traits like reward sensitivity & impulsivity, and these traits relate to substance use

Our movement to and away from punishment underpins personality (traits)

Other personality traits related to BAS

Impulsivity, constellation of traits, sensation seeking, extraversion

Carver & White (1994) - BAS scale which had 3 subscales: reward responsiveness, drive, fun seeking (i.e., impulsivity)

TRAIT IMPULSIVITY

Defined in broad terms = acting without deliberating, poorly planned, behaving prematurely, unduly risky, undesirable consequences


Impulsivity is now recognised as a multifaceted construct

Two-component model (Dawe & Loxton, 2004)

Reward sensitivity = sensitivity & motivation to acquire rewards - dopaminergic system

Rash impulsiveness = can't inhibit approach behaviours in light of negative consequences (deficit in PFC)

Reward sensitivity is imp at the beginning (initial substance use), but after a while rash impulsiveness is imp and as a result the individual begins to have problem substance use (substance misuse) & this further degrades OFC.

UPPS model

There were several contrasting measures for impulsivity, so they factor analysed the measures and found theres 4 components of impulsivity

Lack of premeditation = can't plan ahead, think about consequences i.e., rash impulsiveness

Lack of perseverance = not doing what you're supposed to be doing (not persevering)

Sensation seeking = seeing out thrilling experiences

Urgency = acting impulsively due to elevated emotions
Positive urgency = doing risky things when in a positive mood
Negative urgency = behaving in a risky way when in a negative mood

His own study = meta-analysis, looked at self-reported impulsivity (UPPS model & reward sensitivity), and alcohol use in adolescents (alcohol consumption & problem alcohol use).


Found that sensation seeking highly correlated w/ alcohol consumption
Positive & negative urgency traits highly correlated w. problem alcohol use (this urgency traits relate to how adolescents can't control actions & can't regulate emotions)

Measurements of impulsivity

Self-report questionnaire = e.g., the UPPS model, the BIS-BAS scales, they ask about every day behaviours, or ask about specific situations

Behavioural tasks = administered in lab e.g., sham taste test, abstract, precisely operationalised, general set of tendencies, state components

HOWEVER - there's lots of behavioural tasks measuring impulsivity


Study tried to see if all behavioural tasks can be grouped together - it can be, you measure attention, response inhibition, impulsive decision-making, set shifting = these 4 tasks broadly group together all the different behavioural tasks of impulsivity out there

Stop signal task - can measure response inhibition, but this is a narrow focus, bc different tasks measure different cognitive processes beyond response inhibition, and these all have an impact on impulsive behaviour & substance use behaviour - hard to disentangle which cognitive process is most imp

Also self-report tasks & behavioural tasks for impulsivity don't correlate with each other, but they do correlate with substance use

Study found that drug addicts & alcoholics were high on BAS reward, drive & fun seeking - hence being high on BAS/these impulsive & reward traits are associated with increased substance use

Study on healthy samples also found BAS traits had a relationship with illicit substances & level of alcohol (the higher you are on BAS traits, the more you use illicit and alcohol substances)

Same study he focused on problem cannabis & alcohol use


Found that positive & urgency positively correlated w/ problem alcohol use & w/ problem cannabis use

Another study looked at cannabis frequency & problem use


Found that sensation seeking highly correlated w. cannabis frequency
Also, positive urgency & lack of premeditation highly correlated w. cannabis problem use

Mood induction study - see if urgency trait moderates relationship between mood induction & use of alcohol
3 different mood inductions, sham taste test, how much they drank


Found that those higher in positive urgency/high mood consumed more alcohol - so not just about being in positive mood, but need to be in high positive mood, bc only in the high mood/urgency was there more alcohol consumed

There is a bidirectional relationship - high impulsivity levels can influence heavy substance use, but heavy substance use can affect impulsivity further (by degrading executive functions)

However, there's criticism for this, bc these UPPS traits may be superfluous, where if you control for other traits, then the effect wash out (this also happened in the Stautz paper)

So impulsivity is broken up into reward sensitivity and rash impulsiveness, and this impulsivity is influential throughout the entire process of addiction, as reward sensitivity is imp in the earlier stages, whereas rash impulsiveness is imp in the later stages