Substance Used Disorder

Question 1

Addiction

Answer 1

• A chronic and relapsing behavioural disorder that involved compulsive drug seekings and drug use characterized by:
  
  • Craving - strong urge to take drug
  • Remissions - drug-free period
  • Relapse - drug use recurs, despites negative consequences

Question 2

Dependence

Answer 2

• Dependence - symptoms of withdrawal and tolerance
• Withdrawal - not having the drug causes negative/unpleasant effects. Occurs when blood or tissue concentrations of a substance decline in individuals who had maintained prologned heavy use. Withdrawal symptoms greatly across substance classes.
• Tolerance - when you need more of the drug to get the same effect. Long term stimulation of the receptors results in downregulation of receptors so that the same amount of drugs will cause less stimulation.

Question 3

Reward Circuit

Answer 3

• Neurons in the ventral tegmental area (VTA) release dopamine onto the amygdala, nucleus accumbens, prefrontal cortex, and hippocampus.
  
  • VTA- site of dopamingeric neurons -tells organism whether an environmental stimulus is rewarding or aversive
  • NAc - prinicple target of VTA dopamine neurons. Mediates rewarding effects of natural rewards and drugs of abuse.
  • Amygdala - helps establish associations between environmental causes and whether the experience was rewarding or aversive.
  • Hippocampus - along with amygdala established memories of drug exeriences that are important mediators of relapse
  • Hypothalamus - coordinates individual’s interests in rewards with body’s phsyiological state
  • Prefrontal cortex - provides executive control over choices made in the environment
• Drugs of abuse increase activity of the mesolimbic dopamine pathway.
• Long-term exposure to drugs can alter the reward the pathway.
  
  • Naturally rewarding stimuli are no longer enjoyable
  • Neuroadaptation - repeated exposure to a drug results in long-term changes in brain that lead to a motivational transition
    
    • Loss of spine density
    • Loss of D₂ receptor density
    • Hypersensitvity of frontal cortex to drugs or drug cues
    • Changes in nuclear function and altered rates of transcription - altered expression of these genes leads to changes in neurons, resulting in changes to the neural circuits and ultimately changes in behaviour.

Question 4

Substance Use Disorder

Answer 4

• A cluster of cognitive, behavioural, and physiological symtpoms indicating that individual continues using the substance despite significant substance -related problems. Changes in brain circuitry results in behavioural effects that can manifest as repeated relapse and intense drug cravings
  
  • Withdrawal and tolerance are not necessary for diagnosis, however, they are associated with higher severity
• Occurs in broad range of severities from mild to severe
  
  • Severity is based on a number of symptoms criteiria that are endorsed
    
    • Mild: 2-3 symptoms
    • Moderate: 4-5 symptoms
    • Severe: 6⁺ symptoms

Question 5

Substance Induced Disorder

Answer 5

• Incluces intoxication, withdrawal, and other substance/medications induced mental disorder
• *Only given diagnosis of intoxication if physiological effects are problematic

Question 6

Alcohol Use Disorder

Answer 6

• A problematic pattern of alcohol use leading to clinically significant impairment or distress, as manifested by 2+ occuring with 12-month period

1. Alcohol is oftent aken in larger amounts or over a longer period than was intended
2. There is a persistent desire or unsuccessful efforts to cut down
3. Excessive time is spent in activities nescessary to obtain alcohol, use alcohol or recover from its efforts
4. Craving or strong desires to use alcohol
5. Recurrent alcohol use resulting in failure to fulfill major role obligations at work, school, or home
6. Continued use despite having persistent or recurrent social or interpsonal problems caused by or exacerabated by effects of alcohol
7. Important social, occupational, or recreational activities are given up or reduced because of alcohol use
8. Recurrent alcohol use in situations in which it is physically hazardous
9. Alcohol use is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by alcohol
10. Tolerance - either increase amount needed to achieve effects or decrease effect when using same amount
11. Withdrawal - either chracterisitc withdrawal syndrome for alcohol or alcohol is taken to relieve or avoid withdrawal

Question 7

Medical Consquences of Alcohol Over use

Answer 7

• GI effects - gastritis, stomach or duodenal ulcers, liver cirrhosis, pancreatitis
• Increase rate of cancer of the esophagus, stomach, and other parts of the GI tract
• Hypertension
• Cardiomyopathy
• Wernicke-Korsakoff syndrome - ability to encode new memories is impaired
• Increase suicide risk during severe inotxication
• Liver damage - hepatomegaly, esophageal varics, hemorrhoids
• Tremor, unsteady, gait, insomia, ED
• Feminizing effects in males due to reduced testosterone levels

Question 8

Diagnostic Markers of Alcohol Use

Answer 8

• Blood alcohol concentration - mostt nontolerant individuals display severe intoxication at 200mg/dl
• GGT - modest elevates (>35 units) indicate persistent heavy drinking (8+ daily)
• CDT>29 units indicate persistent heavy drinking (8+ daily)
• MCV - elevated to high normal in heavy drinking (due to toxic effects of alcohol on ethropoiesis)
• LFTs - can reveal liver injury due to heavy drinking

Question 9

Alcohol Intoxication

Answer 9

• Recent ingestion of alcohol
• Clinically significant problematic behavioural or psychological changes that develop during or shortlu after ingestion.
• One or more of the following signs of symptoms develop during or shortly after alcohol use:
  
  • Slurred speech
  • Incoordinated
  • Unsteady gait
  • Nystagmus
  • Impairment in attention or memory
  • Stupor or coma
• The signs of symptoms are not attributable to another medical condition (i.e., delirium) and are not better explained by another mental disorder, including intoxication with another substance (i.e., benzos)

Question 10

Alcohol Withdrawal

Answer 10

• Cessation of (or reudction in) alcohol use that has been heavy and prolonged
• 2⁺ of the following, developing within several hours to a few days after the cessation of (or reduction) in alcohol use described in criteria A
  
  • Autonomic hyperactivity (e.g., sweating or pulse rate >100bpm)
  • Increased hand tremor
  • Insomnia
  • Nausea or vomiting
  • Transient visual, tactile, or audtirou hallucinations or illusions
  • Psychomotor agitation
  • Anxiety
  • Generalized tonic-clonic seziures
• Signs or symptoms cause clinically significant distress or impairment in functioning
• Not due to another medical condition or better explained by another mental disorder

Question 11

Complications of Alcohol Withdrawal

Answer 11

• Minor symptoms - due to CNS hyperactivity - insomnia, tremor, mild anxiety, GI upset, HA, diaphoresis, palpitations
• Withdrawal seizures - generalized tonic-clonic convulsions that ussually occur within 12-48rs after last alcoholic drink, but may occur after only a few hours of absence. Tends to be signular or occur as breif flurry of seziures over short period - recurrent or prolonged seziures suggest altered diagnosis. Untreated withdrawal seizures prgress ot delirium tremens in 1/3 of patients
• Alcoholic hallucinosis - hallucinations that develop within 12-24 hours of abstinence and typically resolve within 24-48 hours. Usually visual and patients are often aware that they are hallucinating, causing distress.
• Delirium Tremens (DT) - 5% of patients undergoing alcohol withdrawal will develop.
  
  • Defined by hallucinations, disorientation, tachycardia, hypertension, hyperthermia, agitation, and diaphoresis insettings of acute reduction or abstience from alcohol.
  • Tends to start within 48-96 hours and lasts 1-5 days
  • See significantly elevated cardiac indices, O2 delivery, and O2 consumption. ARterial pH increases due to hyperventilation, which may be a rebound effect related to the respiratory depressant properities of alcohol.

Question 12

Management Alcohol Withdrawal

Answer 12

• Symptom control and supportive care - alteviating symptoms and identifying and correcting metabolic derangements
  
  • Supportive care includes IV fluids, nutritional supplementation, and freqeuent clinical reassessment
  • Administration of thiamine and glucose to prevent or treat wenickes encephalopathy
• Treatment psychomotor agitation
  
  • Benzos - also used to prevent progression from minor withdrawal to major.
  • Diazepam, lorazepam, and chlordiazepoxide are most frequently used. Generally, long acting benzos with acitive metabolites are preferred. But lorazepram has a shorter half-life and is a good choice for those with severe liver damage.