Substance use disorders Flashcards
Terminology: intoxication, harmful use, dependency, withdrawal
Intoxication: transient state of emotional and behavioural change following drug use. Dose-dependent and time limited
Harmful use: pattern of use likely to cause physical or psychological damage
Dependency: a cluster of physiological, behavioural and cognitive symptoms in which the use of a substance takes on a much higher priority than other behaviours that once had greater value
Withdrawal: transient state occurring whilst readjusting to lower levels of the drug in the body
Theories of dependence
Learning theories
- Classical conditioning: cravings become cues which trigger drug-seeking behaviour
- Operant conditioning: behaviours repeated if they relieve unpleasant experiences (negative reinforcement); drug providing pleasure will be used again (positive reinforcement)
Neurobiological
- All drugs of abuse affect the DOPAMINERGIC MESOLIMBIC reward pathway
- Pathway beings in the ventral tegmental area and projects to the prefrontal cortex and limbic system; prefrontal cortex - role in motivation and plannaing; dopamine release in the nucleus accumbens causes a sensation of pleasure
Features of depedence
Tolerance: larger doses required to gain the same effect as previously
Compulsion: strong desire to use the substance; craving
Withdrawal: physioloigical withdrawal state when the substance is stopped/decreased, demonstrated by characteristic withdrawal S and substance use to prevent or relieve withdrawal Sx.
Problems controlling use: difficulties controlling starting, stopping or amounts used
Continued use despite harm: despite clear problems caused by the substance, the person can’t stop using
Salience (primary): obtaining and using the substance becomes so important that other interests are neglected
Reinstatement after abstinence: tendency to return to the previous pattern and level of use after a period of abstinence
Narrowing of the repertoire: loss of variation in use of the substance.
Differentials for substance misuse
Organic: consider physical causes for certain symptoms (e.g. ataxia, confusion); beware risk of head injury and subdural haematoma from falls
Psychiatric illness: may be primary or comorbid problem
- Depression/mania
- Functional psychosis
- Anxiety disorder
- Personality disorder
- Which is primary prob- psych Sx fit with Sx of substance?; psych Sx while abstinent?; FHx psych illness?
Alcohol - harmful substance use - classification
Pattern of alcohol use that had caused damage to a person’s physical or mental health or has resulted in behaviour leading to harm to health of others
Pattern of alcohol use is evident over a period of at least 12 months if substance use is episodic or at least 1 month if use is continuous
Harm to health of the individual occurs to one or more of the following: behaviour related to intoxication; direct/secondary toxic effects on body organs/systems; a harmful route of administration
Alcohol- dependence syndrome - classification
Disorder of regulation of alcohol use arising from repeated or continuous use of alcohol.
Characteristic feature: strong internal drive to use alcohol which manifested by impaired ability to control use increasing priority given to use over other activities and persistence of use despite harm tor negative consequences
2 of the following:
- Impaired control over substance use - in terms of onset, level, circumstance of termination of use, often accompanies by a subjective sensation of urge/craving
- Substance use becomes an increasing priority in life - takes precedence over other interests, responsibilities, health, personal care
- Physiological features - (indicative of neuroadaptation to the substance as manifested by: tolerance; withdrawal Sx following in cessation or reduction in use; repeated use to prevent or alleviate withdrawal Sx
Aetiology of alcohol abuse
Genetic factors - populations with less effective enzymes - lower dependence
Occupation
Social background
Psychiatric illness
Mechanism of alcohol in brain
Primary target: GABA-A receptor/glutamate receptor
GABA-A receptor
- Acutely: alcohol boosts function -> anxiolysis, sedative
- Chronically: alcohol reduces function as you develop tolerance - countered by alcohol boosting function
Glutamate-NMDA receptor
- Acutely: reduces function
- Chronically: boosts function - associated with impaired memory
Withdrawal leads to:
- Increased glutamate-NMDA activity
- Decreased GABA activity
- Can lead to cell death and seizures
Clinical features of alcohol intoxication
Relaxation and euphoria
At higher level may make people irritable, aggressive, weepy, morose and disinhibited
Impulsivity and poor judgement can make people take risks and behave irresponsibly
Clinical features of alcohol withdrawal
Sx start at 6-12 hrs: tremor, sweating, tachycardia, anxiety, headache, nausea, retching, vomiting, insomnia
Peak incidence of seizures at 36 hrs
Delirium Tremens (med emergency): peak incidence at 48-72 hours
Onset, duration, Sx of Delirium Tremens
Peak incidence at 48-72 hrs post alcohol withdrawal
Duration: 3-4 days
Confusion
Hallucinations (especially visual e.g. formication)
Affective changes (extreme fear and hilarity may alternate)
Gross tremor (especially hands)
Autonomic disturbance (sweating, tachycarida, HTN, fever)
Delusions
5% mortality
Complications of alcohol misuse - general
Physical
Psychological
Wernicke-Korsakoff Syndrome
Social - unemployment, poor attendance/performance at work, domestic violence, separation and divorce; always ask about drink driving
Physical complications of alcohol miuse
Liver: alcoholic hepatitis, cirrhosis
GI: pancreatitis, oesophageal varices, peptic ulcer disease
Neuro: peripheral neuropathy, seizures, dementia
Cancers: bowel, breast, oesophageal and liver
CVS” HTNM cardiomyopathy
Head injuries/accidents
Foetal alcohol syndrome
Psychological complications of alcohol misuse
Depression, anxiety, self harm, suicide
Amnesia
Cognitive impairment (alcoholic dementia, Korsakoff syndrome)
Alcoholic hallucinosis (experience of auditory hallucinations in clear consciousness while drinking - often persecutory/derogatory)
Morbid jealously (overvalued idea or delusion that partner is unfaithful
Wernicke-Korsakoff Syndrome
Wernicke’s Encephalopathy
- Caused by acute thiamine deficiency via chronic alcohol consumption: inadequate nutritional intake, decreased absorption, impaired use by cells
- Thiamine deficiency results in abnormal cellular function in the cerebral cortex, hypothalamus and cerebellum
- TRIAD: confusion + ataxia (wide based gait) + ophthalmoplegia (nystagmus, lateral rectus or conjugate gaze palsies
- MEDICAL EMERGENCY
Korsakoff Psychosis
- When Wernicke’s encephalopathy deteriorates further
- Confusion + anterograde/retrograde amnesia + confabulation
- Irreversible anterograde amnesia - pt register new events, but cannot recall them within a few minutes; confabulate to fill gaps in their memory
Screening tools for potential alcohol misuse
CAGE questionnaire - ever felt need to cut down drinking? people annoyed you by criticising your drinking? ever felt guilty about drinking? need to drink first thing in the morning? score 2/+ suggests excessive drinking
AUDIT - more comprehensive to identify misuse - >15 requires comprehensive assessment
SADQ or LDQ for severity of dependece
CIWA-Ar for severity of withdrawal
APQ for nature and extent of problems arising from alcohol misuse
Investigations for alcohol misuse
Hx/screening tools
FBC - macrocytosis anaemia due to B12 deficiency in alcoholism
LFTs - GGT rises with heavy alcohol use; raised ALT + AST suggests hepatocellular damage
B12/folate
U&Es
Clotting screen
Glucose
Other tests based on presentation
- ECG
- Urine drug screen (amphetamines, heroin, cocaine, methadone, cannabis)
- Hepatitis if IVDU
Management of alcohol dependence
Assessment and preparation: motivation to change; identify type of support needed (reduce consumption/detox/college)
Detoxification
- Allows metabolism and excretion of the substance whilst minimising discomfort
- May be planned or unplanned
- Long acting benzos (e.g. chlordiazepoxide) - replace alcohol and prevent withdrawal Sx; gradually withdrawn and stopped
- Thiamine (vit B1) - prophylaxis against Wernicke’s encephalopathy; best given IV or IM
- Community/home detox for uncomplicated dependency using a fixed-dosage reducing regime of benzos over 5-7 days
- Inpatient detox if Hx of withdrawal fits, comorbid medical or psych illness or if pt lacks support at home
Relapse prevention
Psychological
- CBT
- Problem-solving therapies
- Group therapy (AA)
Medical
- Acamprosate (anti-craving drug)
- Disulfiram (antabuse) - mimics flush reaction to alcohol thereby making alcohol consumption unpleasant