lecture 4 -- the biopsychosocial model - aka medical model of addiction

defining disease model of addiction

• classified it as disease because it is a chemical/biological issue that is primary, progressive chronic, and fatal if untreated. this is mainly focused on the other effects of consumptions, such as liver disease etc.

• obsession to use drugs or drink. has biological, environmental, genetic, neurological sources of origin

• some of this not based on the best science, some of it is

why is drug addiction and alcoholism called a disease?

• fits the traditional medical model of “disease,” which has only the criteria that an abnormal condition is present and causes discomfort, dysfunction, or distress

physical reward potential of addiction

• pleasure centre is not a single centre but is present across brain systems

• there is an increased sense of pleasure, and decreased discomfort

• motivated to seek more, so you use over and over

social learning component of addiction

• we learn how to use drugs and substances, how to get it, how it works, what it feels like, etc

• there is an individual expectation - what you believe will happen - which plays a role in your experience with the substance

• all in order to maximize the potential, both physically and psychologically

• there is also a cultural influence - the community and social groups to which you belong

Peele research about appropriate use

• in cultures where appropriate use of a substance is modelled and socially regulated, addiction is less likely

• of course, there are outliers to this

individual life goals

• remember that chemical abuse patterns are not fixed. your circumstances and life goals change - there are past, present, and future goals

• no one sets out to become addicted

basic tenet of the medical or disease model

• lots of individual behaviour comes from predisposition

• there is no universally accepted disease model that explains addiction. there are loosely related theories that addiction is a pyshco-biomedical process that can be called a disease state. this is not proven.

Jellinek

• shifts view from this being a moral disorder to medical disorder

• addiction recognized as formal disease in 56

• proposed alcoholism to be a progressive/predictable disorder

jellinek’s four stage model

• prealcoholic phase

• prodromal phase

• crucial phase

• chronic phase

• this is a progressive course leading to death

prealcoholic phase

alcohol used for relief from social tension

prodromal phase

first blackouts, preoccupation with use, development of guild

crucial phase

loss of control and a physical dependencech

chronic phase

• loss of tolerance

• obsessive drinking

• alcoholic tremors

• drinking with social inferiors

Jellinek’s other additions to the field

• a hallmark of an alcoholic is that they can’t predict how much they will drink after starting

• addiction isn’t about willpower, but a disease

• removes prejudice of the immoral addict

genetic inheritance theories

• people can be less sensitive to effects of alcohol (less neuronal firing)

• like/dislike of certain substances

• decision making (frontal cortex)

• this makes it harder to quit, and affects withdrawal syndrome

• studies suggest genes account fro 20% to 58% of addiction risk, but there is no single gene that causes addiction

  • this is about vulnerability, not inevitability or destiny

Cloninger’s type 1 and 2 alcoholics

• looks at 862 adoptees raised by non-alcoholic parents, but lots of them became alcoholics

• 2 groups - type 1 is the larger group

Cloninger - type 1 alcoholic

• 75% had biological parents that were alcoholics

• drank in moderation in early adulthood but developed dependence later on

• functioned as responsible adults

• if raised in higher socio-economic family, less likely to become alcoholic

  • this suggests environment has a role in addiction

Cloninger - type 2

• males, more violent than type 1

• fathers were violent alcoholics

• 20% chance of becoming alcoholics regardless of SES

• later studies confirmed these findings, and also finds women to be a part of this subgroup

neuro-biological processes and addiction

• addicts are biologically different from non-addicts, even before use

• addict’s brain acts differently before and after using

• addicts metabolize and bio-transform substances differently

common limbic brain structures implicated in addiction - striatum

• this is the motivational core

• ventral striatum - impulsive actions leading to goals — feelings of attraction, craving, etc. fuelled by dopamine from midbrain

• dorsal striatum

  • activated when goal directed behaviours shift from impulsive to compulsive

  • central to stimulus-response learning — hard to turn signals off

  • also fuelled by dopamine

  • when this is activated, we start looking at level 4 on the continuum

what are the common brain structures implicated in addiction?

• all part of motivational corre

• dorsal and ventral striatum

• midbrain

• amygdala

  • orbitofrontal cortex (OCF) and prefrontal cortex (PFC)

midbrain and addiction

has cells that send dopamine to parts of limbic system and cortex, including striatum, amygdala, prefrontal cortex

amydgala and addiction

• pair of clusters on each side of brain that acquire and maintain emotional associations, so they trigger the same emotion on subsequent occasions

  • focused attention on the source of the emotion

• euphoric recall - related to repeated use

OFC and PFC + addiction

• closely connected to amygdala and accumbens

• creates context-specific interpretations of highly motivated situations - generates expectancies, helps initiate appropriate response

medial prefrontal cortex

• crucial for self-awareness, identity, interpreting others’ thoughts and feelings

• this is why addiction can seem like a very self-centred process

  • gets harder to act like who you are because you have lost your identity and you’re not necessarily aware of the impacts of your actions

dorsal lateral prefrontal cortex

• higher up region

• matures gradually w cognitive development

• brings memories to mind while sorting and comparing

• uses insight, logic, judgement to learn new things

• makes decisions and adjusts previous decisions

• if you lack self-awareness, you’re not changing or adjusting those decisions

• also, if this is not working properly like in addiction, what are you learning?

how does medical model classify addiction today

• mild - presence of 2 criteria

• moderate - presence of 4-5 symptoms or criteria

• severe - presence of 6+ symptoms or critera

11 symptoms of today’s medical model

1. alcohol taken in larger amounts or over longer time than intended

2. persistent desire or unsuccessful efforts to cut down on use

3. lots of time spent on activities needed to obtain substance, use substance, or recover from effects

4. craving or strong desire/urge to use

5. recurrent use resulting in failure to fulfill obligations at work, school, home

6. continued use even though substance has caused or exacerbated recurrent social and interpersonal problems

7. important social, occupational, recreational activities given up or reduced because of use - due to loss of identity and self-awareness

8. recurrent use in situations where it’s physical dangerous

9. use is continued even though you know your problems are caused by substance

10. tolerance

    1. A: need for increased amounts to achieve desired effect, OR

    2. B: markedly diminished effect w continued use of same amount

11. withdrawal

    1. A: characteristic withdrawal syndrome

    2. taking more of substance to relieve or avoid withdrawal symptoms

11 symptoms compared to continuum

• 2ish symptoms, you’ve got a serious social issue, you’re at level 2

• 4-5 symptoms, level 3

• 6+, level 4

alcohol and CNS depressants are thought to control what affective state

loneliness, emptiness, isolation

opiates are thought to control what affective state

rage and aggression

CNS stimulants are thought to control what affective state

depression, sense of depletion, anergia (no energy), low self-esteem