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Medical Model of Addiction

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Presentation on theme: "Medical Model of Addiction"— Presentation transcript:

1 Medical Model of Addiction
Dr. Morag Fisher

2 Conflict of Interest None to disclose

3 Objectives Definition of Addiction Diagnostic Criteria
Contributing factors Neurobiology of addiction, tolerance & withdrawal

4 Addiction – CSAM definition
A primary, chronic disease characterized by impaired control over the use of a psychoactive substance or behaviour. Clinically the manifestations occur along biological, psychological, social & spiritual dimensions. Like other chronic diseases, it can be progressive, relapsing & fatal.

5 Addiction- CSAM definition 2
Common features are change in mood, relief from negative emotions, provision of pleasure, preoccupation with the use of substances or ritualistic behaviour; & continued use of substances &/or engagement in behaviour despite adverse physical, psychological &/or social consequences.

6 DSM IV substance abuse A maladaptive pattern of use leading to clinically significant distress – at least 1 criterion met within a 12 month period Recurrent substance use resulting in a failure to fulfill major role obligations at work, school, or home Recurrent substance use in situations in which it is physically hazardous Recurrent substance-related legal problems Continued substance use despite having persistent or recurrent social or interpersonal problems caused by the effects of substance use Deliberate use of the substance to achieve intoxication Has never met the criteria for Substance Dependence B.

7 Substance Dependence-DSM IV
A maladaptive pattern of substance use leading to clinically significant impairment or distress, as manifested by 3 or more of the following over a 12 month period: -Tolerance –diminished effect with use of the same amount, or increased amount used to achieve intoxication. -Withdrawal – characteristic withdrawal syndrome for the substance, or the same or closely related substance is taken to relieve or avoid withdrawal symptoms. Which is what we defined as addiction

8 Substance Dependence-DSM IV
The substance was taken in larger amounts or for a longer period than was intended There is a persistent desire or unsuccessful attempts to cut down A great deal of time is spent in activities to procure the substance Important activities are given up or reduced because of the substance The substance use is continued despite knowledge of having a physical or psychological problem caused by or exacerbated by the substance use.

9 Anyone who uses a benzodiazepine or an opiate for several weeks can develop physical dependence. This is not sufficient criteria to diagnose addiction.

10 The Hallmark of Addiction
The 4 ‘C’s -Loss of Control of use of the substance -Compulsive use or Craving -Continued use despite adverse Consequences

11 ‘Pseudo – addiction’ This is a term which is used to describe patient behaviors which may occur when pain is undertreated. They may appear to be drug focused & drug seeking , but the behaviors resolve when pain is effectively treated.

12 Contributing Factors : Opioid Risk Tool
Family Hx of Substance Abuse Alcohol Illegal Drugs Rx Drugs Personal Hx of Substance Abuse History of Preadolescent Sexual Abuse Psychological Disease ADHD, OCD, Bipolar, Schizophrenia Depression Webster LR 2005

13 How do Opiates Work Pharmacology
Opiate receptors in the brain: several types - mu, delta, kappa - most important in addiction is the mu receptor Analgesia & euphoria Side effects: respiratory depression, sedation,nausea & constipation, low BP, pupils constrict Increased activity in the ventral tegmental area of the brain resulting in increased dopamine release in the nucleus accumbens = highly addictive Endorphines - our natural opiates

14 Opiod agonist mediates the inhibition of release of GABA - results in disinhibition of of the dopamine neurons - Increased dopamine release at NA

15 Human Molecular Genetics
5 single nucleotide polymorphisms have been identified in the coding region of the human mu opioid gene 3 of these lead to amino acid changes in the receptor Some receptor variants have been associated with increased potency of activation of the receptor Some have some association with increased vulnerability to dependence You are actually inheriting a pattern of responding to the drug differently from the non-addict More research needed

16 Tolerance The brain adapts to the constant presence of the opiate
It takes more drug to get the euphoria Tolerance to respiratory depression doesn’t develop so quickly Therefore there’s always risk of death from overdose Acute morphine ingestion effect is mediated by inhibition of adenyl cyclase - inhibition of CAMP dependent cascade . Long term this is compensated for by an increase in adenyl cyclase Physiologic changes within the cell’s metabolism as the cells adapt to the constant exposure to opiates - they become less responsive to the stimulus at the receptor - so more drug is needed to get the same effect. Tolerance to different effects develops at different pace

17 Withdrawal Neurophysiological rebound in the organ systems on which opioids have their primary actions CNS suppression --CNS over activity Increased CNS noradrenergic hyperactivity primarily at the nucleus ceruleus Large body of research evidence supports this. Methadone Maintenance is associated with reduced use of illicit opiates, reduced IV use , improved health, reduced crime & improved social function re work & family function

18 Opiate Withdrawal Dilated pupils Nausea, vomiting, cramps & diarrhea
Bone pain, headache Chills, sweats, piloerection - “going cold turkey” Anxiety, emotional lability, craving Irritable & insomnia NOT life-threatening (except risk of suicide) NO seizures

19 Withdrawal Worst at day 3-4 Longer withdrawal for methadone
Improving by day 10 Sweats can persist 3-4 weeks Emotional lability will persist for weeks Insomnia can last 6 months or more AT day 10 still c/o sweats , aching , poor sleep, irritable . GI sympt have usua;;y settled.

20 Addiction Treatment Works
Many medical practitioners have a negative attitude towards dealing with addiction Patients DO respond to brief interventions in the doctor’s office, to rehabilitation programs, & to methadone maintenance programs Despite the research evidence our patients still have to deal with the stigma which is attached to the diagnosis of addiction & methadone treatment . Large body of research evidence supports this. Methadone Maintenance is associated with reduced use of illicit opiates, reduced IV use , improved health, reduced crime & improved social function re work & family function Within the community at large & within the medical community Our goal is to educate & improve the understanding of addiction & its treatment

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