Promoting mental health, demystifying mental illness, countering stigma and discrimination

Co-existing Disorders/Dual Diagnosis

What does Dual Diagnosis Mean?

There are many definitions of the term 'dual diagnosis.'
For the purpose of this fact sheet it will be used to describe people with both, a severe mental illness, such as Schizophrenia, Depression or Bipolar Affective Disorder; as well as a severe alcohol and/or drug problem. Many people with a severe mental illness are drawn to substance misuse and may develop dependency problems.
Alternatively, the person may have initially misused substances, which then triggered an underlying mental health problem.

Although no one knows for sure what causes illnesses such as depression, schizophrenia or bipolar affective disorder, most people agree that when these illnesses occur, chemical changes take place in the brain. Drugs and alcohol also cause a chemical change within the brain and, depending on what is being used, either stimulate the brain or slow it down.

Is it difficult to make a dual diagnosis?

Yes, because the symptoms of a person misusing drugs/alcohol are often very similar to the symptoms of mental illness, and vice versa. Alternatively, both problems may exist at the same time.

To make an accurate diagnosis, it is important that as much as possible should be made known about the person. Vital background information can be gathered by talking to the person and, if possible, by talking to their family/whanau and friends.

Where there appears to be a dual diagnosis it is important to try to identify the primary problem so that the most appropriate treatment can be given.

Why might people, with a mental illness, misuse drugs and alcohol?
There may be a number of reasons for this. They may, for example:
  • Feel anxious or wish to 'block out' the symptoms of medication
  • There may be peer pressure or the desire to fit in with a group
  • They may feel that it gives them confidence and boosts their self esteem
  • They may use it because they are bored, lonely or depressed, or because they have difficulties sleeping

For some, a significant minority, substance abuse becomes an addictive pattern of obsessional behaviour.

Which substances are misused?
Although people with mental illness may use or misuse a range of substances such as ecstasy, LSD and amphetamines, misuse of alcohol and/or cannabis is most common.

In understanding the effects of substance use, it is important to state that the effects of any substance will vary from individual to individual according to the quality and quantity of; the substance, age, gender, weight, mood, culture expectations and state of physical and mental health.

Stimulants (uppers) such as speed/cocaine/crack, amphetamines and ecstasy.

Stimulants speed the body up, constrict blood vessels, speed the heart and raise blood pressure and so are particularly risky for people with heart and blood pressure problems. They can also cause or mimic mania, anxiety and/or depression or paranoid psychosis.

Depressants (downers) such as Opiates and Opioids such as Heroin, varieties of Painkillers, Tranquilizers, Benzodiazepines and Alcohol.

Overall, depressants, particularly where there is excessive use, can cause or mimic the depressed mood causing loss of motivation and lack of interest in people and surroundings. Self neglect and even self-harm including suicide may result. It is also easy to overdose on downers, particularly where there is alcohol use.

Hallucinogens such as Cannabis, Ecstasy, LSD and Magic Mushrooms.

Hallucinogens cause intensified and mixed up sensations, illusions, delusions, hallucinations, stimulation and impaired judgement and reasoning. Hallucinogens are generally unpredictable and can trigger a latent mental illness. They can also cause or mimic delusional hallucinations and paranoia associated with a major psychosis.

Volatile substances (different varieties of substances) such as Glue, Aerosols and Lighter Gas fuel.

They act on the central nervous system sometimes as a stimulant but generally as a depressant and can cause loss of inhibitions. 'Sniffers' of all kinds of volatile substances often experience hallucinations.

If someone has a dual diagnosis does that mean there will be additional problems?

Yes. Substance use/misuse by people with a mental illness can:
  • Make symptoms worse.
  • Lead to a relapse and more frequent re-hospitalisation.
  • Cause social and behavioural problems.
  • Make people more vulnerable to suicide.
  • Introduce associated health risks (e.g. HIV, poor eating habits, liver damage).
  • Lead to violence or unsociable behaviour.
  • Lead to difficulties with receiving treatment.
Does drug/alcohol misuse cause mental illness?
Although drug/alcohol misuse is not thought to be a primary cause of mental illness, there is strong evidence to suggest that it can trigger the onset of mental illness in some people with a predisposition to it.

As illegal substances have become increasingly available and fashionable, more people, particularly young people are experimenting with a wider variety of them at a younger age. This includes the excessive use of alcohol.

When mental illness is triggered by alcohol or drug use, is the onset sudden?

The onset can vary. When mental illness has been triggered by alcohol use, its use has often been over a long period of time, often over many years. With illegal substances, the person may have only been taking them for a short period, sometimes on just one occasion, before the mental illness or a drug induced psychosis is triggered.

What sort of help do people with a dual diagnosis need?

People with a dual diagnosis have complex, and many long term needs for care and treatment, including easy access to psychiatric services, psychological and social support and alcohol/drug agencies.

Any programme should be viewed as a long-term commitment on both sides. Strategies that may help the people with a dual diagnosis include:
  • Providing a structured but flexible programme of multi-agency care coordinated by an experienced case manager of key worker.
  • Regular monitoring and assertive outreach services to prevent people 'slipping through the net'.
  • Education to raise awareness about the effects of alcohol/drug use on physical and mental health.
  • Help with developing coping/life skills to help them recognise the symptoms, cope with the anxiety of withdrawal and prevent relapses.
  • Cognitive behaviour therapy and other psychological interventions.
  • Help with developing better support systems within the community.
  • Family support - having to deal with a family member who has both a mental illness and drug/alcohol problems can be a devastating experience for many families and they also need help and support.
Research is continuing to evaluate the effectiveness of providing the above types of help.

Ring for help:

If things are starting to feel out of your control, seek professional help.
  • Talk to the School Guidance Counsellor
  • Talk to a Doctor
  • Ask a family member or friend to find you help
  • Phone the Alcohol Helpline on: 0800 787 797

Resources in Taranaki:

Ngati Ruanui (Kaupapa Maori Service)
P O Box 72, Hawera
Tel: 06 278 3169

Taranaki Health A & D Service (Mainstream)

Taranaki Base Hospital, New Plymouth
Tel: 06 753 7836

Te Rau Pani - Maori Mental Health Services
Maru Wehi Hauora Complex
36 Maratahu Street, New Plymouth. 4343.
Tel: 06 759 7306
Fax: 06 759 7307

The following websites provide information on drug and alcohol issues:

Alberta Alcohol and Drug Commission
Addictions information ABC Fact Sheet on Alcohol

Mental Help Net Alcohol & Substance Abuse Link
An international (Dublin) website with data on most mental illnesses

Mental Health Foundation - NZ
A most useful NZ website with resource data on most mental illnesses

A useful site developed by Child & Adolescent Services, Taranaki Health, working with youth and covering many mental health issues
Like Minds Taranaki gratefully acknowledges the financial support of this website by

The Ministry of Health

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