Substance Misuse Disorder

Question 1

Spectrum of substance misuse

Answer 1

• Recreational use > acute intoxication > harmful use > dependence syndrome

Question 2

Acute intoxication

Answer 2

• Transient condition following use of alcohol or drugs, closely related to dose and following which recovery is usually complete
• Stimulation, excitement or impaired judgement
• Disinhibition
• Reduced (or heightened) conciousness
• Euphoria/Dysphoria
• Impaired motor co-ordination
• Sensory disturbances ( esp Psychadellics)
• Hyperthermia
• Respiratory Depression

Question 3

Harmful substance use

Answer 3

• A pattern of substance use that causes damage to physical health, mental health or social circumstances.
• Diagnosis requires damage to the physical or mental health of the user.
• Social disapproval or adverse social consequences do NOT qualify for diagnosis. (misuse rather than harmful use) Such as:
  
  • Ingestion of excessive amounts
  • “Idiosyncratic” Reactions e.g. Diazepam
  • Method of Administration e.g. IV use
  • Chronic Use e.g.. smoking, alcohol, drugs

Question 4

Dependence syndrome

Answer 4

• A strong desire or sense of compulsion to take the substance
• Difficulties in controlling substance-taking behaviour in terms of its onset, termination, or levels of use
• A physiological withdrawal state when substance use has ceased or been reduced
• Evidence of tolerance, such that increased doses of the psychoactive substances are required in order to achieve effects originally produced by lower doses
• Progressive neglect of alternative pleasures or interests because of psychoactive substance use
• Persisting with substance use despite clear evidence of overtly harmful consequences

Question 5

Withdrawal state

Answer 5

• A group of symptoms of variable clustering, severity & duration depending on substance
• Occur on withdrawal or reduction of use
• Occur after repeated use of a substance
• Indicates dependence

NB - Can be complicated by an acute confusional state

Question 6

Symptoms of withdrawal state

Answer 6

• Benzodiazepines
  
  • Anxiety
  • Agitation
  • Irritability
  • Diaphoresis
  • Confusion
  • Nausea
  • Palpitations
  • Insomnia
  • Seizures
  • Hallucinations
  • Psychosis
• Opioids
• Rhinitis
• Lacrimation
• Yawning
• Dilated pupils
• Diaphoresis
• Insomnia
• Diarrhoea
• Nausea & vomiting
• Piloerection
• Abdominal cramps
• Dysphoria
• Tachycardia
• Hypertension

Question 7

Delirium tremens

Answer 7

• Mortality is 5-10%
• Characterised by:
  
  • Hx of Alcohol
  • Confusion-Nocturnal worsening
  • Hallucinations- Lilliputian.
  • Illusions- Insects
  • Anxiety/Fear
  • Tremulousness
  • Hypertension
  • Tachycardia
  • Tachypnoea
  • Seizures

Question 8

Psychotic disorder

Answer 8

• Psychotic symptoms occur during or after recent (48hrs) psychoactive substance use
• Vivid hallucinations, misidentifications, paranoid delusions, ideas of reference
• Psychomotor disturbances
• Abnormal affect
• Usually improves within 1 month & resolves within 6 months

Question 9

Amnesic syndrome

Answer 9

• Memory impairment (recent memory)
• Absence or defect in immediate recall, of impairment of consciousness and of generalized cognitive impairment
• History or objective evidence of chronic use of alcohol or drugs

Question 10

Residual and late onset psychotic disorder

Answer 10

• Onset of the disorder should be directly related to the use of alcohol or psychoactive substances
• Persists beyond any period of time in which direct effect of the substance

Question 11

Mesolimbic dopamine reward pathway

Answer 11

• Starts in the Ventral Tegmental Area (VTA) which is site of dopaminergic neurons
• Mesolimbic domapine pathway connects it with the Nucleus Accumbens (NAc)
• The NAc has Dopamine sensitive cells & mediates the rewarding effects
• Dopamine is released when an addictive drug is used
• Amygdala & Hippocampus play role in memory & whether experience is desirable
• Prefrontal cortex co-ordinates the information & determines behaviour

Question 12

Reward pathway activation

Answer 12

• Natural rewards
  
  • Food
  • Sex
  • Nurturing
  • Exercise
• Chemical rewards
  
  • Drugs
  • Alcohol
  • Coffee
  • Nicotine

Question 13

Aetiology of addiction

Answer 13

• Social learning model
  
  • Observation of others engaging in addictive behaviour/maladaptive coping leads to copying behaviour
• Disease model
  
  • Addiction is a disease with biological, neurological, genetic and environmental sources of origin
  • Altered brain structure and functioning + neuroadaptation
• Genetic vulnerability
  
  • Children of alcoholics 4x as likely to be alcoholics

Question 14

Cycle of change

Answer 14

Question 15

Psycholosocial interventions in addictions

Answer 15

• Motivational enhancement interviewing
• Brief interventions
• Relapse prevention
• Anxiety management and coping skills (CBT)
• 12 step programmes (AA, NA, CA)
• Peer support (addactions, St Mungo foundation, recovery cafe’s)
• Contingency management
• Therapeutic community/residential rehabilitation

Question 16

Motivational interviewing

Answer 16

• Works on facilitating & engaging intrinsic motivation to change
• Collaborative
• Goal-orientated
• Client- centred
• Guides patient to examine & resolve ambivalence

Question 17

Brief interventions

Answer 17

• F- Feedback of risks
• R- Responsibility Highlighted
• A - Advice to abstain or cut down
• M- Menu of alternative options and activities offered
• E- Empathic Interviewing
• S- Self efficacy enhanced

Question 18

Misuse of drugs act (1971)

Answer 18

• Covers possession & supply of controlled drugs
• Class A: includes heroin, cocaine, MDMA, LSD
• ClassB: cannabis, amphetamines, ketamine, codeine
• Class C: diazepam, GHB, tranquilisers, anabolic steroids

Question 19

Psychoactive substances act (2016)

Answer 19

• Offence to produce, supply or offer to supply any psychoactive substance if substance likely to be used for its psychoactive effects & regardless of its potential for harm
• Intended to act against shops and websites supplying NPS

Question 20

Substance use mortality

Answer 20

• Mortality in drug addicts is 7x higher than the general population
• Injecting drug users mortality is 12-22x> drug using peers
• Alcohol is strongest single predictor of suicide
• Most common cause of drug-related death is opoids followed by benzos
• Generally poly-drug use

Question 21

Opoids

Answer 21

• Analgesic, Euphoric & Anxiolytic effects
• μ(Mu), κ (Kappa) & δ (Delta) receptors
• Most abused substances are μ receptor agonists
• μ receptors mediate analgesia, respiratory depression, euphoria (in some), drowsiness & constipation
• Mediate dopamine release in VTA
• Seek help from services in 20s
• Detox Vs maintenance prescription
• Lofexidine ( α2 adrenergic agonist) or Buprenorphine for detox- high relapse rates
• Methadone & Buprenorphine for substitute prescriptions (effective for reducing heroine use)
• Rapid loss of tolerance
• High risk of OD if missed doses and re-instated at usual dose
• Need for re-titration after 3 days
• Management of overdose:
  
  • Symptoms – respiratory depression, pinpoint pupils, ↓ levels consciousness
  • Treatment – Naloxone – competitive opioid anatgonist, reverses depression of CNS & respiratory system caused by opioids; can be given nasally, IM, IV
  • Naloxone’s rapid blockade of opioid receptors often produces fast onset of withdrawal symptom

Question 22

Benzodiazepines

Answer 22

• Enhance GABA at the GABAA receptors
• Ligand gated ion channel
• When activated. Selectively conduct Cl ions, causing hyperpolarisation which reduces likelihood of action potential
• Sedative, hypnotic, anxiolytic & muscle relaxant effects
• Licit- Prescribed. Normal dose but unable to stop
• Illicit- often excessive doses (eg 20x 10mgs daily)
• Rate of dependence increases with duration of use
• Use for 4 weeks or less rarely leads to significant withdrawals or dependence
• Management of overdose:
  
  • Sedation, drowsiness, ataxia, slurred speech, coma, respiratory depression
  • Higher risk if combined with alcohol or other CNS depressants
  • Supportive treatment
  • Flumazenil IV

Question 23

Amphetamines

Answer 23

• CNS stimulants
• Enhance release of Dopamine, Norepeniphrine & Serotonin from pre- synaptic neurons
• Block catecholamine reuptake
• Norepheneprine >sympathomimetic
• Dopamine > Central stimulant/reward
• Serotonin > Mood
• Rapid onset of effects
• Therapeutic use in ADHD
• Withdrawal can develop rapidly with methamphetamine

Question 24

MDMA (Ecstasy)

Answer 24

• A substituted amphetamine
• Serotonergic
• Partially stimulant & partially hallucinogenic
• Harm reduction advice regarding maintaining hydration & avoiding overheating.

Question 25

Cocaine

Answer 25

• CNS stimulant & local anaesthetic
• Short acting
• Direct action on Dopamine neurons blocking reuptake
• Also blocks reuptake of Serotonin & Norepinephrine
• Causes increased energy, increased confidence, euphoria & diminished need for sleep
• Can precipitate psychosis
• Associated with sudden cardiac death
• Crack cocaine- more potent
• Strong complusion to take & psychological dependence
• Dysphoric “Come down”

Question 26

Cannabis

Answer 26

• Herbal cannabis contains >400 compounds > 60 are cannabinoids
• 9Tetrahydrocannabinol (THC) most potent psychoactive
• Cannabis receptors are inhibitory G protein linked
• CB1 receptors (CNS & PNS)
• CB2 receptors (immune)
• THC increases release of DA from the Nucleus accumbens & prefrontal cortex
• Impaired cognitive & psychomotor performance
• Euphoria, heightened perceptual sensitivity, depersonalisation & derealisation
• Vasodialtion, suffused sclerae, postural hypotension, syncope
• Tolerance
• Psychological dependence
• Withdrawals: restlessness, insomnia, anxiety, aggression, anorexia, muscle tremor & autonomic effects
• Link with onset of Schizophrenia
• Long term use may lead to subtle forms of cognitive impairment affecting memory, concentration & the integration of complex information or to an amotivational syndrome

Question 27

Volatile gases

Answer 27

• 1 death/week in UK
  
  • Sudden cardiac death
  • Asphyxiation
  • Accidents when intoxicated
• Rapid intoxication- euphoria, nystagmus, hallucinations, psychomotor retardation, blurred vision, poor co-ordination
• Rashes around nose & mouth
• Occular or oropharangeal irritation
• Chronic users may develop diffuse cerebral, cerebellar and brainstem atrophy with white matter changes & leukoencephalopathy
• Hearing loss, cerebellar signs, peripheral neuropathy, lethargy, memory less etc
• Harm reduction advice
  
  • Not to take when alone
  • Reduce risk of asphyxiation

Question 28

Ketamine

Answer 28

• NMDA antagonist but also has effects at Dopamine & Opioid receptors
• Anaesthetic- used in Paediatrics & field medicine
• Treatment of neuopathic pain
• Acute experience is dose dependent
• Short t1/2
• ?may be beneficial in treatment resistent depression
• Tolerance develops rapidly
• Intense cravings related to pain & cramps
• 1/3 experience anxiety, sweats & shakes in withdrawal
• Acute risks include:
  
  • Cardiac
  • Accidental Death
  • Unprotected Sex
• Chronic use associated with cognitive deficits
• Can lead to ketamine bladder
  
  • 30% of regular Ketamine users
  • Errosion of urothelium
  • Inflammation leads to revascularisation
  • Urge incontinence
  • Decreased bladder compliance
  • Decreased bladder volume
  • Detrusor overactivity
  • Painful haematuria
  • Bilateral hydronephrosis and
  • Renal papillary necrosis
  • On stopping use
    
    • 1/3 recover
    • 1/3 no change
    • 1/3 deteriorate

Question 29

G Drugs GBL and GHB

Answer 29

• Gamma Butyrolactone (GBL)
• Pro-drug for Gamma hydroxybutyric acid (GHB)
• Recreational use
• Effects similar to alcohol
• Recreational Use in MSM
• Heavy use/dependence assoc with severe withdrawals