Search for notes by fellow students, in your own course and all over the country.
Browse our notes for titles which look like what you need, you can preview any of the notes via a sample of the contents. After you're happy these are the notes you're after simply pop them into your shopping cart.
Title: Addiction
Description: These notes are aimed at those studying a neuroscience degree, but also could come in useful for those studying psychology. They aim to give a somewhat brief yet detailed outline of theories that may underpin addictive behaviour including biological theories featuring the reward pathway (mesolimbic pathway) and psychological models (moral model, dual diagnosis model and addiction as a disease model) These lecture notes were adapted by a final year neuroscience student, from a lecture given during the Behavioural Sciences module at King's College London
Description: These notes are aimed at those studying a neuroscience degree, but also could come in useful for those studying psychology. They aim to give a somewhat brief yet detailed outline of theories that may underpin addictive behaviour including biological theories featuring the reward pathway (mesolimbic pathway) and psychological models (moral model, dual diagnosis model and addiction as a disease model) These lecture notes were adapted by a final year neuroscience student, from a lecture given during the Behavioural Sciences module at King's College London
Document Preview
Extracts from the notes are below, to see the PDF you'll receive please use the links above
Addiction
Addiction definition: The condition of taking drug excessively and being unable to cease doing so with adverse
effects
What is addiction?
1)
2)
3)
4)
Compulsion to seek and consume a drug
Loss of control in limiting its consumption
Negative physiological and psychological state when drug access is prevented (dependence)
The individual needs to progressively consume increasing amounts of the drug in order to get the same
feeling as before (tolerance)
Drug addiction refers to a situation where drug procurement and administration appear to govern the organism’s
behaviour, and where the drug seems to dominate the organism’s motivational hierarchy
...
It carries no connotations regarding the drug’s potential adverse effects, the
social acceptability of drug usage, or the physiological consequences of chronic drug administration (Jaffe 1975)
...
Although drug addiction frequently has adverse medical consequences, it
is usually associated with strong social disapproval, and it is sometimes accompanied by the development of physical
dependence, these factors do not define addiction nor are they invariably associated with it
...
Addiction can also defined as a primary, chronic disease of brain reward, motivation, memory and related circuitry
...
This
is reflected in an individual pathologically pursuing reward and/ or relief by substance use and other behaviours
-‐
It is characterised by inability to consistently abstain, impairment in behavioural control, and craving,
diminished recognition of significant problems with one’s behaviours and interpersonal relationships, and a
dysfunctional emotional response
...
Without treatment or engagement in recovery activities, addiction is progressive ad can result in
disability or premature death
...
g
...
• Impulse-‐control disorders are defined by the failure to resist an impulsive act or behaviour that may be harmful to
self or others
...
• However this re-‐classification is already controversial
...
This pathway is also known as the mesolimbic pathway
...
The pathway connects the ventral tegmental area, which is located in the midbrain, to the nucleus
accumbens
...
It
is the most significant neural pathway in the brain in which changes occur in all known forms of addiction
Different drugs, same ultimate effect:
-‐
-‐
-‐
-‐
Cocaine and related stimulants block the dopamine reuptake transporter located on the presynaptic
membrane, thus increasing synaptic dopamine
Nicotine induces cells in the ventral tegmental area to release dopamine into the nucleus accumbens
Opiates mimic some of dopamine’s actions in the cells o the nucleus accumbens
Alcohol and opiates enhance dopamine release by quieting neurons that inhibit dopamine-‐ secretion
A new link between mental health, addiction and depression has been discovered with may be related to parenting
functions
-‐
-‐
-‐
-‐
-‐
-‐
-‐
-‐
-‐
-‐
-‐
-‐
-‐
-‐
Motivational pathways regulating a healthy response to an infant can be altered by drug abuse
Systems coping with a loss of social attachment may become abnormally active in depression
Pathways coping with demands and need of protection of an infant may start to malfunction and give rise to
anxiety
Relationship between pup care and reward systems in the brain
Hypothesis that mesocorticolimbic pathways mediate mother-‐offspring interactions in rats
Dopamine is released and c-‐fos is activated in nucleus accumbens following pup exposure in mothers
VTA or nucleus accumbens lesions disrupt maternal behaviour
Considering cocaine intake, one of the most potently rewarding psychostimulant, as a model for reward it
has been found out that at Day 8 postpartum females prefer pups to cocaine but at Day 16 cocaine appears
more attractive than pups
In mothers cocaine intake (4
...
S
...
Oxytocin is considered to be directly affected by cocaine exposure
...
Cocaine activates mesocorticolimbic and nigrostriatal DAergic pathways
...
In non-‐addicted mothers
infant cues are highly reinforcing and activating mothers’ reward circuit
...
Studies in alcohol craving alcoholics saw that there was a reduction in the availability of D2-‐like receptors in the
striatum which correlates with the craving behaviour
Models of Addiction
-‐
-‐
-‐
Moral model
Dual diagnosis model
Disease model
The Moral Model of Addiction
-‐
-‐
-‐
-‐
Addictive behaviour results from a lack of moral fibre ad or character strength
Addicts started to use drugs because of their weakness in the face of difficult life events
Based on the idea that if addicts really wanted to stop taking drugs they could at any time
Addicts should be encouraged to try harder
Dual Diagnosis Model
-‐
-‐
-‐
-‐
As much as 50% of the population with mental illness also has substance abuse problems
This has led to the idea that addiction is secondary to some psychological condition
For instance individuals with mental illness might use drugs to self-‐medicate
However often addiction is the only disorder that should not fit with the dual diagnosis model
Addiction as Disease Model (ADM)
-‐
-‐
-‐
-‐
The fundamental idea is that addiction is a primary rather than a secondary disease
Addicts are compelled by a physiological and psychological need to take the drug
Addicts experience horrible physical and psychological symptoms when trying to stop
Addiction is a physiological illness with a distinctive natural progression
Jellinek (1946-‐ 1952)
Stages of alcoholism
1)
2)
3)
4)
Pre-‐alcoholic phase
Prodromal phase
Crucial phase
Chronic phase
Criticisms of ADM
-‐
-‐
-‐
-‐
There is no independent means of verifying the existence of the disease
Assumes a cut-‐off between addiction and non-‐addicted
Minimises situational and interpersonal factors
Social context determines what is considered addiction and what is not
Ethical Implications of ADM
1) How should one treat addictions who commit crimes to fund their addiction?
2) If genetic constitution may lead to addiction, are addicts morally culpable for their actions?
3) Should addicts be “treated” or “punished”?
The Addictive Process Hypothesis
-‐
Psychoactive substance use disorders, bulimia nervosa, pathological gambling, and sexual addiction share an
underlying biopsychological process
Evidence FOR this hypothesis
-‐
-‐
-‐
-‐
-‐
-‐
A person diagnosed with an addictive disorder is at higher risk than the general population to develop other
addictive disorders
Biological relatives of a person with an addictive disorder are at higher risk than the general population to
develop other addictive disorders
Symptoms of different addictive disorders respond similarly to a number of psychiatric medications (e
...
antidepressants)
Drug abusers, alcoholics, bulimics, pathological gamblers share a number or psychological traits as revealed
by psychometric tests
Different addictive disorders share the same neurobiological substrate i
...
reward system
Individuals with an addictive disorder show other manifestations of psychopathology, such as symptoms of
another psychiatric disorder, prior to the onset of the addictive disorder
Factors that contribute to the development of addiction include; biological vulnerability and psychosocial factors
Evidence from Animal Studies
• Deroche-‐Gamonet et al
...
(2004) conclude that addiction results from the interaction of 2 factors:
(i)
(ii)
The degree of exposure to drugs (since addiction-‐like behaviour appears only after extended access to
cocaine)
The degree of vulnerability in the exposed individual (because, despite a similar drug intake in all subjects,
addiction-‐like behaviour appears in a minority of rats)
...
Human Studies of Heritability
• 25% of the sons of alcoholics become alcoholics
...
• MZ twins have higher concordance for alcoholism than DZ twins in most (but not all) studies
...
Genetic effect is mediated by:
-‐
-‐
-‐
Acute sensitivity to the reinforcing effect of alcohol
Fast development of tolerance
Increased withdraw sensitivity
How is the genetic effect mediated?
• The dopamine D2 receptor gene (DRD2 TaqIA) is associated with dopamine receptor density
• The A1 allele is associated with reduced number of dopamine binding sites and increased likelihood to develop
substance abuse
• The A2 allele is associated with increased number of dopamine binding sites and reduced likelihood to develop
substance abuse
• Craving in alcohol abusers carrying the A1 gene can be reduced by the dopamine agonist bromocriptine
...
g
...
g
Title: Addiction
Description: These notes are aimed at those studying a neuroscience degree, but also could come in useful for those studying psychology. They aim to give a somewhat brief yet detailed outline of theories that may underpin addictive behaviour including biological theories featuring the reward pathway (mesolimbic pathway) and psychological models (moral model, dual diagnosis model and addiction as a disease model) These lecture notes were adapted by a final year neuroscience student, from a lecture given during the Behavioural Sciences module at King's College London
Description: These notes are aimed at those studying a neuroscience degree, but also could come in useful for those studying psychology. They aim to give a somewhat brief yet detailed outline of theories that may underpin addictive behaviour including biological theories featuring the reward pathway (mesolimbic pathway) and psychological models (moral model, dual diagnosis model and addiction as a disease model) These lecture notes were adapted by a final year neuroscience student, from a lecture given during the Behavioural Sciences module at King's College London