Psychiatry: Substance and Alcohol Misuse

Substance Misuse

Epidemiology

  • One in 10 UK adults and 17% of those aged 11–15 have used illicit drugs. There is a strong association with younger age (11–24 years) and male gender.
  • Between 3 and 4% of teenagers and adults have used class A drugs in the last year.
  • Cannabis is the most common illicit drug used, followed by cocaine, ecstasy, amphetamines and amyl nitrate.

Classification

ICD-10 classifies substance use disorders according to (1) substance and (2) type of disorder. The latter include the following:
Acute intoxication: transient disturbances of consciousness, cognition, perception, affect or behaviour following the administration of a psychoactive substance (PS).
Harmful use: damage to the individual’s health and adverse effects on family and society.
Dependence: Figure 17.2 shows the signs of dependence.
There is usually an associated neglect of important social, occupational or recreational activities.
Withdrawal state: physical and psychological symptoms occurring on absolute or relative withdrawal of a substance after repeated, usually prolonged and/or high-dose use.
Psychotic disorder: psychosis during or immediately after use, with vivid hallucinations, abnormal affect, psychomotor disturbances and delusions of persecution and reference.
Amnesic disorder: memory and other cognitive impairments caused by substance use (e.g. alcohol).

Residual and late onset psychotic disorders: effects on behaviour, affect, personality or cognition that last beyond the period during which a direct PS effect might be expected (e.g. flashbacks).

Aetiological factors

  • Availability and peer pressure.
  • Desire for pleasurable effects. All drugs of abuse activate the dopamine system in the mesolimbic reward pathway.
  • Prescribed drugs may be misused.
  • Psychiatric illness:
    • Impulsivity or anxiety may increase drug use.
    • Patients with borderline and antisocial personality disorders are much more likely to take illicit drugs.
    • Conversely, substance misuse can exacerbate low mood and anxiety, or precipitate psychosis.
    • Management of patients with psychiatric and coexisting substance use disorders (dual diagnosis) should optimally involve a multidisciplinary team trained to manage both disorders.

Management

  • Can be in residential rehabilitation, hospital or community.
  • Contingency management programmes are evidence based.
    Drug users receiving methadone or who misuse stimulants are offered rewards (e.g. vouchers for goods or services) for negative drug tests or harm reduction (e.g. hepatitis and HIV tests).
  • Effective psychosocial interventions include cognitive behavioural therapy, motivational interviewing and
    self-help groups.
  • Medication can be useful (see specific substances below).
  • Infection (HIV and hepatitis C) is the greatest risk associated with injecting drug use; harm-reduction strategies aim to minimise infection (e.g. needle exchange) and improve safety.

Specific substances

Opiates

  • Figure 17.1 lists the opiates of abuse and their effects.
  • Ten per cent of opiate misusers become dependent, but only 10% of these ever seek help; 2–3% die annually. Of the remainder, 25% are abstinent at five years and 40% at 10 years.
  • Tolerance and withdrawal develop quickly. Early withdrawal symptoms (24–48 hours) include craving, flu-like symptoms, sweating and yawning. Mydriasis (dilation of the pupil), abdominal cramps, diarrhoea, agitation, restlessness, piloerection (‘gooseflesh’) and tachycardia occur later (7–10 days).
  • Opiate detoxification treatment usually lasts 4–12 weeks:
    • Methadone (opioid agonist) or buprenorphine (opioid partial agonist) are first line; they are less euphoriant and have a relatively long half-life than opioids of abuse.
    • Lofexidine is sometimes used for short detoxification treatments or where abuse is mild or uncertain.
    • Consider a contingency management programme, with psychosocial support for at least six months.
  • In maintenance therapy, methadone or buprenorphine is prescribed at a dose higher than required to prevent withdrawal symptoms. This can reduce craving, prevent withdrawal, eliminate the hazards of injecting and stop illicit drug use. The aim is progression from maintenance to detoxification and abstinence.
  • Naltrexone (opioid antagonist) blocks the euphoric effects and is occasionally used to help prevent relapse.
  • Signs of overdose (often accidental) include miosis and respiratory depression and may require naloxone.

Hallucinogens

  • See Figure 17.1. Magic mushrooms have similar but less prolonged effects to LSD.

Stimulants

  • Cocaine may be sniffed, chewed or injected intravenously.
    • Its effects (restlessness, increased energy, abolition of fatigue and hunger) resemble hypomania and last about 20 minutes.
      Visual/tactile hallucinations of insects (formication) and paranoid psychoses occur.
    • Post-cocaine dysphoria, with sleeplessness and intense depression, precedes withdrawal (depression, insomnia and craving).
    • ‘Crack’ (a purified, very addictive form of cocaine) is smoked.
      The crack ‘high’ is extremely short and, on withdrawal, persecutory delusions are common.
  • Amphetamines (‘speed’), taken orally or intravenously, cause euphoria, increased concentration and energy, mydriasis, tachycardia and hyperreflexia, followed by depression, fatigue and headache. Acute use may cause psychosis.
  • Methamphetamine is chemically related but more potent, longlasting and harmful; it can be ingested, snorted or smoked (as crystal meth).
  • Naphyrone and mephedrone are also closely related to amphetamines.
    They were originally manufactured as ‘legal highs’ but are now class B drugs.
  • Amyl nitrite and butyl nitrite and isobutyl nitrite (called ‘poppers’) are sniffed from small bottles. They deliver a short, sharp high. Side effects include severe headache and feeling faint. They are toxic and can be fatal if swallowed.

Other drugs

  • Cannabis: see Figure 17.1.
  • Benzodiazepines produce dependence, withdrawal (including seizures) and tolerance. Dependence is often iatrogenic, although benzodiazepines are also common street drugs.
  • Solvents
    • Typically sniffed, principally by boys (aged 8–19 years) (a red rash around the mouth and nose may be a sign of abuse).
    • Initial euphoria is followed by drowsiness.
    • Psychological dependence is common but physical dependence is rare.
    • Chronic abuse results in weight loss, nausea, vomiting, polyneuropathy and cognitive impairment.
    • Toxic effects (can be fatal): bronchospasm, arrythmias, aplastic anaemia, hepatorenal and cerebral damage.
  • Phencyclidine (PCP; ‘Angel Dust’) is usually smoked. Its effects include euphoria, peripheral analgesia and impaired consciousness or psychosis, which may require antipsychotics.
  • Khat:
    • used particularly by men from Somalia and Yemen;
    • contains cathinone, an amphetamine-like stimulant causing excitement and euphoria;
    • not a controlled substance in the UK.

Alcohol Misuse

Alcohol abuse is regular or binge consumption of alcohol sufficient to cause physical, neuropsychiatric or social damage.

Safe limits

  • A ‘unit’ of alcohol (10 mL, 8 g) is roughly a small glass of wine, a pub single of spirits or a half pint of beer.
  • The conventional safe drinking limits are 21 units per week for men and 14 for women, with at least two drink-free days each week.
  • The UK government gives guidelines for maximum daily use (<4 units a day for men, <3 units for women), reflecting concerns about binge-drinking.
  • Much smaller amounts may be hazardous to a foetus.

Classification

ICD-10 classifies alcohol use disorders using the same system as for other psychoactive substances.

  • Acute intoxication is characterised by slurred speech, impaired coordination and judgement, labile affect and, in severe cases, hypoglycaemia, stupor and coma. Differential diagnosis includes other causes of acute confusion, particularly head trauma.
  • Acute withdrawal reflects the degree of previous dependence and usually occurs within one to two days of abstinence.
    • It is characterised by malaise, nausea, autonomic hyperactivity, tremulousness, labile mood, insomnia and transient hallucinations or illusions (usually visual).
    • Seizures are a recognised complication.
    • Severe withdrawal, or ‘delirium tremens’ (‘shaking delirium’), occurs in 5% of withdrawals and has a mortality of up to 15%, partly as a result of other medical complications.
  • Alcohol dependence:
  • Psychotic disorders related to alcohol use include:
    • alcoholic hallucinosis (usually threatening, second-person voices in a clear sensorium)
    • jealousy (paranoid delusions about infidelity).
  • Amnesic disorder: for example, Korsakoff’s psychosis.
  • Residual and late onset disorders: include depression and dementia.

Epidemiology

  • Prevalence rates worldwide vary widely and are related to overall consumption levels, availability and price.
  • In the UK, heavy drinking (an average of 8 units/day for men and 6 units/day for women) is reported by 23% of men and 9% of women; younger people are more likely to exceed safe limits.
  • The prevalence of alcohol dependence is 6% in men and 2% in women. Rates are particularly high in medical inpatients and are increasing in women and adolescents.
  • Alcohol abuse and dependence often begin in the early to mid-20s, at a time when most people begin to moderate their drinking as their responsibilities increase.

Detection and screening

  • A fifth of primary care attenders have an alcohol use disorder.
  • The detection of disorders can be difficult because they are not usually clinically obvious, but is crucial to:
    • enable appropriate treatment
    • avoid long-term complications
    • avoid withdrawal from unplanned abstinence (e.g. after surgery).
  • Professionals should have a high index of suspicion in medical inpatients and those with mental illness or two or more drink-driving offences.
  • Many cases can be detected by documenting a typical drinking week.
  • Screening questionnaires are also helpful:
  • Collateral history can be revealing.
  • Physical examination may reveal alcoholic stigmata, particularly signs of liver disease (jaundice, spider naevi, palmar erythema, gynaecomastia) and peripheral neuropathy.
  • Macrocytosis without anaemia and raised γ-glutamyl transferase (GGT), alanine and aspartate aminotransferase (ALT and AST) or carbohydrate deficient transferrin (CDT) indicate recent harmful use.

Aetiology

This is multifactorial. Factors include the following:

  • A strong genetic component (around 60%), which appears to be multigenic. Genetically determined alterations in alcohol metabolism may partially explain this, with those at low risk producing more (hangover-causing) acetaldehyde; 50% of Japanese people have an unpleasant ‘flush reaction’ on drinking alcohol due to a mutation in the acetaldehyde dehydrogenase 2 gene. There is often a positive family history of depression.
  • Occupation: high-risk groups include the armed forces, doctors, publicans, journalists.
  • Cultural influences: low rates are reported in Jews and Muslims, and high rates in Scottish and Irish people.
  • The cost of alcoholic drinks.
  • Behavioural models stress:
    • learning by imitation (modelling)
    • social reinforcement
    • the association between drinking and pleasure (classical conditioning)
    • avoiding withdrawal symptoms (operant conditioning).
  • Risk increases in the presence of chronic psychiatric or physical illness, particularly if complicated by chronic pain. There is an association with mood and anxiety disorders.

Complications

  • Neuropsychiatric complications:
    • Wernicke’s encephalopathy:
  • peripheral neuropathy
  • erectile or ejaculatory impotence
  • cerebellar degeneration
  • dementia.
  • Other physical complications: drinking damages almost every organ system in the body.
  • Social complications include unemployment, marital difficulties, criminality, prostitution, homicides, domestic violence, accidental deaths, road accidents and suicides.
  • Psychiatric complications:
    Repeated heavy drinking is associated with:
    • a 40% risk of temporary depressive episodes
    • suicidal ideas and attempts
    • severe anxiety
    • insomnia.
      These often improve within two to four weeks of abstinence.
  • Foetal alcohol syndrome (from drinking in pregnancy) is characterised by:
    • decreased muscle tone
    • poor coordination
    • developmental delay
    • heart defects
    • a range of facial abnormalities.

Management

  • Abstinence is the usual goal for treatment of dependence, although sometimes it is controlled drinking.
  • Achieving abstinence requires acute detoxification:
    • This should be in hospital if there is a risk of delirium tremens or withdrawal seizures, or the person is a child or vulnerable (e.g. cognitively impaired or lacking support).
    • Initially high but rapidly tailing sedation (almost always a benzodiazepine, such as chlordiazepoxide or diazepam) is usually needed to control withdrawal symptoms and prevent seizures.
    • Treatment of delirium tremens is usually with lorazepam or antipsychotics (e.g. haloperidol or olanzapine).
    • Treatment also includes rehydration, correction of electrolyte disturbance, and oral or parenteral thiamine.
  • Motivational interviewing is client-centred counselling that explores ambivalence to seeking treatment, drinking cessation or both. It may help problem drinkers in denial achieve insight and a desire to change.
  • Psychological therapies (individually or in groups) may promote maintenance of abstinence or controlled drinking (i.e. within safe limits). They are useful for:
    • sustaining motivation
    • learning relapse-prevention strategies
    • developing social routines not reliant on alcohol
    • treating coexistent depression and anxiety.
  • Self-help groups (e.g. Alcoholics Anonymous) are effective; they reduce pro-drinking activities and social ties.
  • Medication may help maintain abstinence after detoxification:
    • Disulfiram blocks alcohol metabolism, inducing acetaldehyde accumulation if alcohol is ingested, with resultant flushing, headache, anxiety and nausea.
    • Acamprosate acts on the γ-aminobutyric acid (GABA) system to reduce cravings and risk of relapse.
    • Naltrexone, an opioid-receptor antagonist, has similar therapeutic effects.
  • Prevention measures include:
    • increasing taxation on alcohol
    • restricting its advertising or sale
    • school alcohol education: this reduces long-term alcohol use, risky alcohol-related behaviour and binge-drinking.

Prognosis

  • Continued alcohol problems increase the rate of early death by a factor of three or four. The most common causes are heart disease, stroke, cancers, liver cirrhosis, accidents and suicide.
  • Only 15% of those with alcohol use disorder seek treatment; those who do have a better prognosis.