Ruling Out Other Potential Diagnoses

To be sure that your symptoms are due to schizophrenia, doctors need to rule out other possible causes. 1,2

The main things that need to be ruled out are:1-4

A physical health condition,e.g. tumour, sepsis
Effects of prescribed or recreational drugs,e.g. opioid painkillers, amphetamines
Other mental health conditions,e.g. bipolar disorder, severe depression

What happens first: talking

Before anything can be ruled in or ruled out, you’ll need to share a lot of information with your doctor. Try to remember that healthcare professionals are there to help you, and want you to feel happier and healthier.

Your doctor and you

If you don’t like talking about it, you could write down beforehand some of the things you’ve been experiencing and either read it out or let them read it for themselves. It’s always best to be as honest and open as you can, so your doctor can advise you properly.

Going though it all thoroughly

The medical history might be taken by your GP, who would then refer you to a specialist, or by the specialist themselves. If you do get referred from a GP to a specialist, you might have to go through all your medical history again – this can be a bit frustrating, but it’s so that the doctor who will be treating you can be sure they’ve got all the details correct and haven’t misunderstood anything.

Your doctor and your family

Your doctor may also want to talk to someone you live with such as a parent or partner – this is so that the doctor can get a full picture of your life and decide on the most appropriate next steps to take.

What happens next: testing

Once your doctor has all the relevant information from you and/or your family, the next thing is to rule out other possible causes for your symptoms.4

Ruling out physical health conditions

Some illnesses and health issues can cause psychiatric symptoms that might look like schizophrenia.1,2

To see if there is something like this causing the symptoms, doctors may carry out some tests. These tests might include:

A urine test2
A blood test2
A CT or MRI scan6

Ruling out effects of drugs

There are some prescribed (medicinal) drugs and some recreational (illegal) drugs that can have an effect on your mind and behaviour.2

To see if something like this is causing problems, your doctor might look back at your medical history or medical records to see if there are any medications on there that could be having this effect.2

Psychosis

They may also want to do a urine test. This will be to see if there are any drugs in your system that might be causing issues – either medicines or recreational drugs.7 Some drugs can cause psychosis, which is when someone loses touch with reality.3 Drugs that may cause psychosis include:

high-dose corticosteroids, used to treat a wide range of conditions including asthma, ulcerative colitis and multiple sclerosis2,8
levodopa and dopamine agonists, used to treat Parkinson’s2,9,10
certain anticonvulsants, used to treat seizures and nerve pain2,11
opioids taken as painkillers – these are prescribed to help manage pain but they can become addictive.12 Examples of opioids are codeine, tramadol, morphine and oxycodone 12,13
opioids taken as recreational drugs – these are bought from dealers or other illicit routes. Examples include heroin, or the misuse of illegally obtained tramadol14-16
other illegal drugs such as amphetamines or cocaine2
cannabis 17

Remember that healthcare professionals will not judge you for taking illicit drugs. They just want to help you be as healthy as possible.

Losing touch with reality – seeing, hearing, feeling and sensing things in a way that’s very different to people around you.

Ruling out other mental health conditions

Delusions, hallucinations, negative symptoms and cognitive difficulties can each happen with other mental health conditions such as bipolar disorder or depression.1,4,18,19

Diagnostic criteria

A list of signs and symptoms of a particular condition.

There has to be a certain number of symptoms, and they have to have been experienced for a certain amount of time.

This can make it difficult for doctors to be sure that your symptoms are definitely caused by schizophrenia. To work out exactly what’s causing these symptoms, doctors have to eliminate other possible options carefully.

For a doctor to make a formal diagnosis of schizophrenia, they have to be sure that the person they’re examining meets the diagnostic criteria.

The diagnostic criteria for schizophrenia in the UK are:20

For at least a month you have had one or more of the following symptoms:

Delusions
Hallucinations
Hearing voices
Incoherent speech (not making sense when you talk)
Negative symptoms, such as flat effect (when you don’t express any emotions)

The symptom(s) have had a major effect on your life, making it difficult to:

Work
Study
Do daily tasks (e.g. shopping, cooking, personal hygiene)

Other possible causes of the symptom(s) have been ruled out

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