Download Medical Model of Addiction

Medical Model of Addiction
Dr. Morag Fisher
Conflict of Interest
• None to disclose
Objectives
• Definition of Addiction
• Diagnostic Criteria
• Contributing factors
Neurobiology of addiction, tolerance &
withdrawal
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.
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.
DSM IV substance abuse
A.
A maladaptive pattern of use leading to clinically
significant distress – at least 1 criterion met within a
12 month period
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B.
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
Has never met the criteria for Substance Dependence
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.
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.
Anyone who uses a
benzodiazepine or an opiate
for several weeks can develop
physical dependence.
This is not sufficient criteria to
diagnose addiction.
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
‘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.
Contributing Factors :
Opioid Risk Tool
1. Family Hx of Substance Abuse
a. Alcohol
b. Illegal Drugs
c. Rx Drugs
2. Personal Hx of Substance Abuse
1. Alcohol
2. Illegal Drugs
3. Rx Drugs
3. History of Preadolescent Sexual Abuse
4. Psychological Disease
1. ADHD, OCD, Bipolar, Schizophrenia
2. Depression
Webster LR 2005
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
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
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
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
Opiate Withdrawal
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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
Withdrawal
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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
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