11/14/24, 10\:43 AM Substance Misuse Disorder

Substance Misuse Disorder

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Substance misuse disorder\: consumption of substances causing social, psychological, physical, or legal problems; most
common substance is cannabis, followed by cocaine and ecstasy.
Alcohol misuse\:
Subtypes of substance misuse disorder\: low-risk use, hazardous substance use, harmful substance use, and substance
dependence (requires at least two\: impaired control, increasing priority, tolerance, withdrawal).
Pathophysiology of addiction\: a
GABA, and dopamine; dopamine release reinforces substance use; chronic exposure causes neuroadaptation and
withdrawal symptoms.
Alcohol misuse\: hazardous drinking (>14 units/week), harmful drinking (causes physiological complications), alcohol
dependence (craving, tolerance despite negative e
Clinical features of alcohol misuse\: short-term harm (poisoning, accidents), liver cirrhosis, withdrawal symptoms (tremors,
hallucinosis, delirium tremens).
Investigations for alcohol misuse\: FBC (raised MCV, platelets), LFTs (increased GGT, AST\:ALT > 2\:1), haematinics
(B12/folate), TFTs.
Management of alcohol misuse\: alcohol detox (chlordiazepoxide, oxazepam), naltrexone, acamprosate, disul
psychological interventions, prophylactic thiamine.
Opioid misuse\: includes morphine, heroin, codeine; causes euphoria, sedation, respiratory depression; withdrawal causes
sympathetic overactivity (rhinorrhoea, diarrhoea).
Investigations for opioid misuse\: HIV, hepatitis B/C, tuberculosis testing, U&E, LFTs, drug levels.
Management of opioid misuse\: opioid detox (methadone or buprenorphine reduction), counselling, rehabilitation.
Benzodiazepine misuse\: includes diazepam, oxazepam, lorazepam; causes altered mental status, respiratory distress;
withdrawal causes tremor, agitation, seizures.
Management of benzodiazepine misuse\: assisted withdrawal, supportive treatments.
CNS stimulants\: amphetamine, cocaine; causes tachycardia, hypertension, mydriasis; withdrawal causes dysphoria,
lethargy.
Management of CNS stimulant misuse\: supportive, managing withdrawal symptoms.
Hallucinogens\: LSD, marijuana, ecstasy, PCP; causes euphoria, hallucinations, psychosis; speci
substance.
Management of hallucinogen misuse\: supportive treatment, medically supervised detox, cognitive behavioural therapy,
managing withdrawal symptoms.
Article 🔍
A comprehensive topic overview

Introduction

Substance misuse disorder is the consumption of substances that leads to the involvement of social, psychological,
physical, or legal problems.
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Among people aged 16-59, the most common use substance is cannabis, followed by cocaine and ecstasy. 2
On the other
hand, alcohol misuse is the
18.6% higher than in previous years.
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This article will cover alcohol, CNS depressants, CNS stimulants, hallucinogens, and investigations for substance misuse
disorder.

Aetiology

Figure 1 shows the subtypes of substance misuse disorder, which include low-risk use, hazardous substance use, harmful
substance use, and substance dependence.
Figure 1. The subtypes of substance
misuse disorder.
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Substance dependence requires at least two of the following\:
1. Impaired control over substance use
2. Increasing priority over other aspects of life or responsibility
3. Psychological features suggestive of tolerance and withdrawal

Pathophysiology of addiction

Substance misuse a
also a
When an individual consumes a substance, this a
dorsal striatum in the basal ganglia. 4
The release of dopamine gives o
system and positively reinforce the behaviour of substance consumption. This process is known as operant conditioning
and is the basis of addiction and cravings.
Some substances, such as alcohol and opioids, interact with the inhibitory neurotransmitter GABA, which disrupts the
equilibrium between GABA and glutamate. It is believed that the number of natural stimulants (glutamate) and natural
sedatives (GABA) are roughly the same. When an individual consumes substances, this disrupts the equilibrium as there
are more sedative hormones (GABA).
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When exposed chronically, this results in neuroadaptation. The brain will upregulate the natural stimulants to achieve
equilibrium. Withdrawal symptoms occur when there is a sudden drop in GABA, resulting in disrupted homeostasis and
too much glutamate. The excess natural stimulants lead to withdrawal symptoms such as anxiety, sweating, and shaking.

Alcohol

According to UK guidance, the threshold for alcohol consumption is 14 units a week spread evenly over three days or
more. It is important to discuss the di
Hazardous drinking is when an individual consumes more than 14 units of alcohol a week, which may increase their risk of
harm. Harmful drinking is when the pattern of alcohol consumption directly causes physiological complications and
illnesses as discussed below. Finally, alcohol dependence is characterised by craving and tolerance of alcohol
consumption despite the negative complications experienced.
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Clinical features

Alcohol misuse can result in short-term harm including alcohol poisoning and accidents.
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It can also a
present with bleeding oesophageal varices, hepatic failure, and stigmata of liver diseases. Other chronic physiological
consequences are discussed in the section below.
Withdrawal symptoms can be experienced after a few hours of alcohol cessation. Within 6-12 hours, patients can
experience tremors, and autonomic arousal (e.g. tachycardia, fever, pupillary dilation, and increased sweating).
Between 12-48 hours of cessation, patients can experience alcohol hallucinosis (typically auditory or tactile). Between 72-
96 hours, patients can present with delirium tremens. They may experience altered mental status, agitation, and tactile
hallucination.

Investigations

Relevant laboratory investigations in the context of alcohol misuse include\:
Full blood count\: raised MCV, raised platelets, anaemia
Liver function tests\: increased GGT, AST\:ALT > 2\:1
Haematinics (B12/folate)\: alcohol can cause folate de
Thyroid function tests

Screening questionnaires

The AUDIT-C questionnaire is a common screening tool that looks at the risk of dependency of alcohol misuse.
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Other questionnaires include the SAD-Q questionnaire which looks at the severity of alcohol dependence and the CAGE
questionnaire. For more information, see the Geeky Medics guide to alcohol history taking.

Management

The main intervention for alcohol dependence is alcohol detox. However, this method can cause serious withdrawal
symptoms, leading to tremors, seizures, and delirium tremens. Therefore, alcohol detox should be carefully planned, and
specialist alcohol services should be involved.
Medications can be used during the detox phase to help with the symptoms of alcohol withdrawal. Chlordiazepoxide (20-
40 mg QDS) is often prescribed and monitored over the
hepatic impairments and the elderly.
Naltrexone is an opiate blocker that makes alcohol less enjoyable and less rewarding. It can be administered as an
injection once a month or oral tablets. Common side e
site, and increased liver enzymes. It is contraindicated in opiate use and patients with liver failure.
Acamprosate is a medication that increases GABA and decreases excitatory glutamate which reduces cravings. It has a
good side e
Disul
unpleasant symptoms such as
Patients should avoid alcohol for 24 hours before taking disul
taking the medication, they must avoid all contact with alcohol. Disul
disease, psychosis, and those felt to be at high risk of suicide.
Patients should be o
prescribe prophylactic oral thiamine, if they are malnourished or in acute withdrawal, or su
disease.

Complications

Alcohol misuse can cause multiple physiological complications including\:
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Neurological\: ischaemic stroke, encephalopathy, seizures, peripheral neuropathy
Cardiovascular\: increased rate of myocardial infarction and stroke, hypertension, dilated cardiomyopathy
Hepatology\: alcoholic liver disease, liver cirrhosis, liver pancreatitis
Oncology\: increased risk of head and neck cancer, oesophageal cancer, liver cancer, breast cancer, colorectal cancer
Psychiatric\: alcoholic hallucinosis, delirium tremens, Wernicke-Korsako
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Wernicke-Korsako
Alcohol prevents the absorption of thiamine by blocking thiamine pyrophosphate synthetase, resulting in thiamine
de
The main symptoms of Wernicke encephalopathy are ataxia, confusion and ophthalmoplegia.
Korsako
hallucinations
The treatment is the intravenous replacement of thiamine (e.g. Pabrinex).

Opioid misuse

Opioid misuse includes the use of morphine, heroin, and codeine. Opioids are central nervous system depressants that
slow brain activity and relax muscles.

Clinical features

Opioid misuse can cause multiple physiological and psychological e
Physiological\: euphoria and reduced pain, sedation, respiratory depression, miosis, constipation, skin warmth and

Psychological\: apathy, disinhibition, drowsiness, impaired judgment and attention, slurred speech
When withdrawing from opioids, increased sympathetic nervous system activity causes rhinorrhoea, lacrimation,
diarrhoea, pupillary dilation, piloerection, tachycardia, and hypertension.

Investigations

Relevant laboratory investigations in the context of opioid misuse include\:
HIV and hepatitis B/C\: due to the increased risk of blood-borne infection is greater through needle sharing
Tuberculosis testing
Urea & electrolytes
Liver function tests and clotting screen\: to check hepatic function
Drug levels\: to check for drug toxicity
There are several drug screening questionnaires which can be used\:
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Drug abuse screening test (DAST)\: assess drug use in the past 12 months
CAGE-AID (adapted to include drugs)
Addiction severity index (ASI)\: looks at the e
health
Clinical opiate withdrawal scale (COWS)\: rates common signs and symptoms of opiate withdrawal and monitors
symptoms

Management

The main intervention for opioid misuse is opioid detox using methadone reduction. An alternative to this is
buprenorphine reduction. It can be helpful to refer the patient for counselling and rehabilitation.

Complications

If taken in large doses, opioids can cause death. Of all drugs taken in overdose, opioids have been consistently shown to
be the most likely to cause death. For more information, see the Geeky Medics guides to opioid overdose and the acute
management of an opioid overdose.
Opioid misuse also increases the risk of blood-borne diseases such as HIV, hepatitis B, and C.
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Benzodiazepines

Benzodiazepine misuse includes the use of diazepam, oxazepam and lorazepam. Benzodiazepines are another example of
central nervous system depressants.

Clinical features

The clinical features of benzodiazepine misuse include\:
Physiological e
overdosed
Psychological e
Withdrawal from benzodiazepines may result in a wide range of clinical features including tremor, nausea & vomiting,
tachycardia, postural hypotension, headache, agitation, malaise, transient illusions or hallucinations, paranoid ideation and
seizures.

Investigations

The clinical institute withdrawal assessment scale - benzodiazepines (CIWA-B) can be used to determine the severity of
withdrawal from the substance.

Management

The main intervention for benzodiazepine misuse is assisted withdrawal and supportive treatments.

Central nervous system stimulants

Amphetamine use (e.g. Adderall and methylphenidate) and cocaine are central nervous system (CNS) stimulants.

Clinical features

CNS stimulants activate the sympathetic nervous system which causes symptoms such as tachycardia, hypertension, and
mydriasis.
Patients using cocaine may develop tactile hallucinations and chest pain.
Clinical features of CNS stimulant withdrawal include dysphoria, lethargy, psychomotor agitation, craving, increased
appetite, insomnia, and bizarre dreams.

Investigations

Screening tools used for CNS stimulants are the drug abuse screening test (DAST), CAGE-AID (adapted to include drugs)
and addiction severity index (ASI).

Management

There is no speci
withdrawal symptoms.

Hallucinogens

Hallucinogens include lysergic acid diethylamide (LSD -
'acid'), marijuana, ecstasy and phencyclidine or phenylcyclohexyl
piperidine (PCP). When consumed, they can cause euphoria, visual and auditory hallucinations and psychosis.

Clinical features

Hallucinogens mainly cause visual or auditory hallucinations and the feeling of euphoria.
Speci
LSD\: lethargy, psychomotor agitation, craving, insomnia, and unpleasant dreams
Marijuana\: increased appetite and conjunctival injection
Ecstasy\: bruxism, hyperthermia, hyponatremia, and hepatotoxicity
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PCP\: loss of painful stimuli, vertical nystagmus, psychosis with hallucination, violence, and agitation

Investigations

Screening tools used for hallucinogens are the drug abuse screening test (DAST), CAGE-AID (adapted to include drugs)
and addiction severity index (ASI).

Management

There are no speci
medically supervised detox by slowly tapering the dose, referral to a rehabilitation centre, cognitive behavioural therapy,
and treatment of withdrawal symptoms.

References

NICE. O v e r v i e w \: D r u g u s e d i s o r d e r s i n a d u l t s \: Q u a l i t y s t a n d a r d s N I C E . Available from\: OLINK]
[LINK]
E n g l a n d a n d W a l e s , U K . GOV.UK.
John, A.B.and E. (2021) A l c o h o l -s p e c i LINK]
A l c o h o l -s p e c i
Neurotorium. S u b s t a n c e u s e d i s o r d e r s a n d o t h e r a d d i c t i o n s - h i s t o r y , d e
b o o k s h e l f . Available from\: [LINK]
[LINK]
NICE. A l c o h o l p r o b l e m d r i n k i n g , N I C E . Available from\: [LINK]
Alcohol Rehab Guide. A l c o h o l d e t o x (2022). Available from\: [LINK]
U.S. Department of Health and Human Services. A l c o h o l' s e
A l c o h o l i s m . Available from\: [LINK]
SMART. S c r e e n i n g a n d a s s e s s m e n t t o o l s f o r d r u g a n d a l c o h o l u s e (2015). Available from\: [LINK]

Reviewer

Dr Rana Moharam
Consultant in Child and Adolescent Psychiatry

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Contents

Introduction
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Aetiology
Alcohol
O i id i
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