This document discusses dual diagnosis, which refers to co-occurring mental health and substance use disorders. It provides definitions of dual diagnosis from medical taxonomy and from Williams, who describes four types: primary mental illness leading to substance use; primary substance use leading to psychiatric issues; dual primary diagnoses occurring simultaneously; and common etiological factors leading to both. The document analyzes four case studies according to Williams' definitions and provides recommendations for practitioners, including engagement, assessment, avoiding assumptions, optimism, harm reduction, information sharing, and multi-agency collaboration.

1. Dual Diagnosis

2. Definitions
In this resource, ‘dual diagnosis’ means a co-existing mental health and
substance use problem.
It is also a term used to describe people with a
mental health problem and a learning disability.
This definition does not apply to this resource.
For a co-existing mental health and substance misuse problem,
medical taxonomists have created the term ‘dual diagnosis’ but it is a
general term which can describe different presentations of co-morbid
mental distress and substance use.

3. Definitions of dual diagnosis
(Williams, 2002)
Williams describes different types of dual diagnosis although they can
oversimplify a condition and risk being labelling:
• Primary mental illness with substance misuse – consequences of the
illness lead to substance misuse.
• Primary substance misuse with psychiatric sequelae – misuse leads
to psychiatric symptoms/conditions i.e. alcohol & depression,
stimulants & psychosis.
• Dual primary diagnosis, two unrelated conditions exist at the same
time but subsequently may interact.
• Common aetiology conditions – bio/psycho/social factors lead to both
conditions i.e. family dysfunction and conduct disorder with drug use.

4. Discussion points
• Many of us may have experienced at least mild forms of emotional
need and the use of substances. Here, though we discuss where
these two factors become problematic for the person involved.
• Notice that ‘mental disorder’ refers to a diagnosable condition in the
definition such as schizophrenia or depression, and ‘substance use’
refers to alcohol or other drugs, not tobacco, caffeine or addictive
behaviours such as gambling.
• Some people can ‘fall between the cracks’ of services if they have a
mental or emotional problem which is not recognised as a mental
disorder, such as stress or bereavement.
• People can have problems with an addiction which is not recognised
as such, for example, smoking, or a behavioural habit such as self
harming or over eating.

5. What are we talking about?
Some case examples
The following four case examples illustrate Williams’ definition.
Look at these case examples and see which case applies to which
category in Williams’ definition above.

6. Case 1
A young man with schizophrenia and alcohol
dependency – he complains of a decrease in
mood and high anxiety without alcohol.
He finds the alcohol helps reduce the voices he
hears and helps him to sleep.
He binges on alcohol when feeling stressed
which results in relapse of his psychosis.

7. Case 1 possible answer
Primary mental illness with substance misuse – consequences of the
illness leading to substance use.

8. Case 2
An elderly widower lives on his own in an isolated
community.
He has poor mobility and stays indoors most of the
time.
He is physically dependent on alcohol and drinks
every day.
He is prescribed anti-depressants by his general
practitioner.

9. Case 2 possible answer
This case could be either/both:
• Dual primary diagnosis, two unrelated conditions exist at the same
time but subsequently may interact .
• Common aetiology conditions – bio/psycho/social factors leading to
both conditions.

10. Case 3
A middle-aged male presents with a
history of habitual long-term heavy
cannabis use.
His lifestyle revolves around cannabis
use, socially and at home. He finds it
reduces his anxieties in the short term.
He has frequent acute psychotic
episodes and admissions to hospital

11. Case 3 possible answer
Primary substance misuse with psychiatric sequelae – misuse leads to
psychiatric symptoms/conditions i.e. alcohol & depression, stimulants &
psychosis.

12. Case 4
An alcohol dependent middle aged woman has PTSD
(post traumatic stress disorder), depression and
agoraphobia.
She was attacked and raped in street and severely
injured 15 years ago.
She drinks to overcome her fear of going out and to
reduce her anxiety and flashbacks of the event. She
can not go out without alcohol.
She has experienced paranoid thoughts about
neighbours and people in the street.

13. Case 4 possible answer
Primary mental illness with substance misuse – consequences of the
illness lead to substance misuse.

14. What the general health and
social care practitioner can do
• It can be daunting to have a patient or client
with highly complex needs.
• It is difficult to know how to prioritise and you
can be left feeling overwhelmed by the
problems the person has. This is normal.
• However there are some key actions that
everyone can take who comes into contact with
someone who has dual diagnosis in terms of
their substance use.

15. Recommendations for all
(Crome et al. 2009)
• Engage the person in considering their substance use/misuse. This
may need an understanding and non-judgemental approach, and
focusing on the small steps first. See the resource on How to talk to
about substance use.
• Screening and assessment. This should include the person’s social
history as well as their substance use history. It is usually the
person’s psychosocial needs which present barriers to change. See
the resource on Basic assessment tools and strategies.
• Avoid stereotypical assumptions about people who misuse
substances. This will present a barrier to engaging and working with
the person.

16. Recommendations (cont.)
• Promote optimism. As you can see in the resource on Recovery and
Asset-based Approaches, a key element to helping someone change
their behaviour around substances is to encourage hope and focus on
their strengths. If you as a practitioner believe the person can be
successful in changing, your patient or client can have hope and use
the strengths they have.
• Use harm reduction in the first instances. Do not expect someone to
make big changes. It is better to reduce the harm which comes from
their use than alienate them by expecting large gains. So, using more
safely, using less, using knowledgeably: all these are useful
intervention outcomes.

17. Recommendations (cont.)
• Give useful information. You need to be
knowledgeable about harms, where to go for
help, support resources. This way, you can
pass this on to your patient or client.
• Also, work with others. Dual diagnosis requires
a multi-agency approach. Share care with those
who are best placed to assist or lead in case
management.

18. References
Crome, I., Chambers, P., Frischer, M., Bloor, R. & Robers, D. (2009). The relationship
between dual diagnosis: substance misuse and dealing with mental health issues. SCIE
Research Briefing 30. SCIE.
Williams, H (2002) Dual Diagnosis – an Overview: Fact or Fiction?, in, Rassool, (Ed),
Dual Diagnosis, Substance Misuse and Psychiatric Disorders, Blackwell Science,
Oxford.