What Are Schizophrenia Spectrum Disorders


Schizophrenia is a chronic mental health disorder that causes patients to become unable to distinguish their thoughts and ideas from reality. This phenomenon is also known as psychosis. Patients with psychosis experience hallucinations (seeing and hearing things that aren’t there) and delusions (odd and incorrect thoughts).1

Schizophrenia spectrum disorders are disorders that cause psychosis. Spectrum disorders include schizophrenia itself, alongside schizoaffective disorder, brief psychotic disorder and multiple others.

Differentiating schizophrenia from other schizophrenia spectrum disorders can be helpful as each has different signs and symptoms. They also last for different lengths of time and have different prognoses. Schizophrenia is typically regarded as the most severe of the schizophrenia-spectrum subtypes, partially due to its high suicide rate.1

This article will discuss the key characteristics of psychotic disorders, the types of schizophrenia spectrum disorder, and the risk factors, investigation and management for these disorders.

What are the key characteristics of schizophrenia spectrum disorders?

The key symptoms of schizophrenia-spectrum disorders include:1

  • Visual hallucinations (seeing things that aren’t there)
  • Auditory hallucinations (hearing voices that aren’t there)
  • Incorrect and odd beliefs about reality, known as delusions

Other symptoms that are also seen in schizophrenia-spectrum disorders include:1

  • Inability to think clearly
  • Loss of interest in everyday activities
  • Loss of normal emotions
  • Low mood and depression
  • Anxiety
  • Strange speech
  • Strange movements or posture

Research shows that social withdrawal may be the first symptom to occur in a patient’s first psychotic episode.2 This is followed by hallucinations and/or delusions. Symptoms related to low mood, loss of interest and loss of normal emotions tend to occur later on.

Patients with schizophrenia spectrum disorder also tend to have a lack of understanding and awareness of their disorder.3 This can make treatment harder, especially if a patient does not have a good support system. Unfortunately, those who have good insight into their condition are more likely to suffer from mood symptoms.3

Another symptom that is often associated with schizophrenia is catatonia.4 Catatonia is a disorder of movement, speech and behaviour. It can cause patients to sit or stand in an excessively rigid posture or a strange position, to perform strange movements or to speak strangely. This includes patients repeating back the speech they have heard or saying things randomly that seem unrelated to the conversation.

Types of schizophrenia spectrum disorders


Schizophrenia is a chronic psychotic disorder causing so-called ‘positive’ and ‘negative’ symptoms. ‘Positive’ symptoms describe symptoms causing new phenomena, for example, hallucinations and delusions. ‘Negative’ symptoms describe symptoms that are a loss of one’s normal self, for example, a loss of energy, emotion or motivation.1

The prognosis of patients with schizophrenia is generally poor, with a positive outlook only predicted for about 20% of patients who are diagnosed.1  The majority of patients will instead have multiple relapses of their disease, in which they will have psychotic episodes that require treatment. 

Schizoaffective disorder

Schizoaffective disorder is a psychotic disorder in which patients have symptoms of schizophrenia as well as significant mood symptoms.5 Rather than just experiencing low mood, as in schizophrenia, patients may have ‘manic’ episodes in which their mood is unnaturally elevated, which can often cause irrational and unpredictable behaviour. This occurs alongside symptoms such as visual or auditory hallucinations and odd thoughts (delusions). For this reason, it has been described as a cross between bipolar disorder and schizophrenia.5

Schizoaffective disorder, like schizophrenia, is thought to have strong genetic links and runs in families.5

Brief psychotic disorder and schizophreniform psychosis

Brief psychotic disorder and schizophreniform psychosis are both diagnoses given to patients who experience a psychotic episode with symptoms that last under 6 months before resolving.1 These are diagnosed in retrospect.

The difference between these two terms is that brief psychotic disorder tends only to include ‘positive’ psychotic symptoms, whereas schizophreniform psychosis can include all the symptoms of schizophrenia. 

Delusional disorder

Delusional disorder is a term given to patients who experience incorrect thoughts (delusions) but do not experience the other symptoms of schizophrenia, for example, hallucinations.1 Symptoms must have occurred for a month before diagnosis. Examples of delusions seen in delusional disorder include a ‘grandiose’ delusion, in which a person believes they have special powers or abilities that put them above others, or a ‘persecutory’ delusion, in which the patient believes those around them are trying to harm them.

Body dysmorphic disorder, in which a person has incorrect beliefs about the way their body looks, can sometimes be classified as a subtype of delusional disorder.1 However, it is also commonly classified as a subtype of obsessive-compulsive disorder (OCD) instead and tends to be a lot milder than the other psychotic disorders listed above.6 

Risk factors 

Researchers are still trying to figure out all of the risk factors for schizophrenia and what can increase the likelihood of a person developing it. Some known risk factors for developing schizophrenia spectrum disorders include:

  • Genetics and family history
  • Complications in pregnancy
  • Childhood trauma
  • Chronic stress

Family history is the most well-established risk factor for developing a psychotic disorder. It is estimated that between 60-80% of cases of schizophrenia are inherited.1 The combination of these genetic risk factors on top of experiences in childhood is thought to make an individual more likely to develop schizophrenia or related psychotic disorders.

On top of this, some researchers support the hypothesis that complications during pregnancy increase the risk of schizophrenia. This idea came after a high percentage of those diagnosed with schizophrenia had their mothers report complications either during pregnancy or labour.1 It is thought that some pregnancy complications may cause physical changes in the brain, and these could increase the risk of schizophrenia-spectrum disorders later in life. 


One popular hypothesis for the cause of symptoms in schizophrenia is the overactivity of the hormone dopamine.1 Most antipsychotic medications are dopamine blockers, and their success seems to support this conclusion. Additionally, drugs that increase the amount of dopamine in the brain, such as cocaine or levodopa (used in treating Parkinson’s disease), are associated with psychotic symptoms at high amounts.

Multiple physical changes in the brain have also been associated with the development of schizophrenia-spectrum disorders. Despite this, explanations for why and how they occur are unclear. The most common change seen on brain imaging is enlargement of the ventricles of the brain, which are fluid-filled spaces holding a substance called CSF, or cerebrospinal fluid.7 CSF flows around the brain and down the spinal cord, cushioning them and bringing nutrients in and waste products out. 


There is no simple test that can be done to diagnose schizophrenia spectrum disorders. Instead, diagnosis is based on symptoms, and psychiatrists use specific criteria for this. The main criteria used are the DSM-5 and the ICD-11. Sometimes, symptoms have to be present for a certain amount of time to meet these criteria, meaning a proper diagnosis can be delayed. Also, as schizophrenia spectrum disorders are quite similar, diagnoses may change over time if new symptoms arise.1 

Other diagnoses will be ruled out using a variety of questions and tests. This may include blood tests as well as drug tests, as drug-induced psychosis is a common cause for psychotic symptoms presenting in the same way as schizophrenia. If a patient has recently hit their head, they may be asked to go for a brain scan.

Treatment Approaches

There are several ways to manage schizophrenia spectrum disorders, and typically, this depends on the patient and their symptoms.

To manage psychotic symptoms, drugs called antipsychotics are prescribed. There are two categories of antipsychotics, known as ‘typical’ and ‘atypical’ antipsychotics.1 Typical antipsychotics work by blocking receptors in the brain for the hormone dopamine, which is thought to cause schizophrenia symptoms if in excess. Atypical antipsychotics are a newer type of medication that works by blocking dopamine receptors as well as receptors of another hormone called serotonin. Patients are initially started on an atypical antipsychotic, such as olanzapine, aripiprazole or risperidone.8 Antipsychotics can come in tablet form or as injections.

If two standard antipsychotics are tried and don’t work to reduce symptoms, a stronger typical antipsychotic called clozapine may be prescribed. Clozapine is very effective but has significant side effects.8 Its most notable side effect is that it can stop your immune system from working properly, so patients taking clozapine have to have regular blood tests to ensure they have enough functioning immune cells. They must also seek advice from a healthcare professional immediately if they get symptoms of illness, such as a sore throat, as it could more easily develop into a serious infection and potentially lead to sepsis.8 

Talking therapies are also used to manage schizophrenia spectrum disorders. This is most commonly cognitive behavioural therapy (CBT) for psychosis.1 CBT for psychosis is recommended for all patients who are diagnosed with a schizophrenia spectrum disorder. It involves a block of sessions in which the patient can reframe their thoughts and ideas. The main aim of CBT for psychosis is to reduce distress and improve quality of life.9 Family therapy is also sometimes used for patients with schizophrenia who have a strong family support network.1

Living with a schizophrenia spectrum disorder

Being diagnosed with a schizophrenia spectrum disorder is difficult, not just due to the symptoms but also due to the stigma surrounding the disorder. Patients with schizophrenia and psychotic disorders have reported in various studies the different coping strategies that have helped them, ranging from taking the correct medication and partaking in CBT to spending time with friends and finding new hobbies.10. Establishing ways to cope is essential for the well-being of both patients and their families and friends.


In conclusion, there is a wide range of schizophrenia-spectrum disorders, and although they are treated similarly, they have different diagnostic criteria and prognoses. Schizophrenia is still a disorder with a lot of stigma surrounding it, and working to remove as much of this as possible is important in allowing patients to seek support without worry or embarrassment.


  1. Semple D, Smyth R. 5 Schizophrenia and related psychoses. In: Oxford handbook of psychiatry. 4th ed. Oxford Academic; p. 567.
  2. Patel KR, Cherian J, Gohil K, Atkinson D. Schizophrenia: overview and treatment options. Pharmacy and Therapeutics. 2014 Sep;39(9):638–45. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159061/ 
  3.  Smith TE, Hull JW, Israel LM, Willson DF. Insight, Symptoms, and Neurocognition in Schizophrenia and Schizoaffective Disorder. Schizophrenia Bulletin. 2000;26(1):193–200. Available from: https://pubmed.ncbi.nlm.nih.gov/10755681/ 
  4. Wilcox JA, Reid Duffy P. The syndrome of catatonia. Behavioral Sciences [Internet]. 2015 Dec [cited 2023 Aug 25];5(4):576–88. Available from: https://www.mdpi.com/2076-328X/5/4/576
  5. Miller JN, Black DW. Schizoaffective disorder: A review. Ann Clin Psychiatry [Internet]. 2019 Feb 1 [cited 2023 Aug 25];31(1):47–53. Available from: https://doi.org/10.3109/10401239109147967
  6. Bjornsson AS, Didie ER, Phillips KA. Body dysmorphic disorder. Dialogues in Clinical Neuroscience [Internet]. 2010 Jun 30 [cited 2023 Aug 25];12(2):221–32. Available from: https://www.tandfonline.com/doi/full/10.31887/DCNS.2010.12.2/abjornsson
  7. DeLisi L. The Concept of Progressive Brain Change in Schizophrenia: Implications for Understanding Schizophrenia. Schizophrenia Bulletin. 2008 Mar;34(2):312–21.
  8. Schizophrenia | bmj best practice [Internet]. [cited 2023 Aug 25]. Available from: https://bestpractice.bmj.com/topics/en-us/406/treatment-algorithm
  9. Anthony Morrison, Sarah Barratt. What Are the Components of CBT for Psychosis? A Delphi Study. Schizophrenia Bulletin. 2010 Jan;36(1):136–42. Available from: https://pubmed.ncbi.nlm.nih.gov/19880824/ 
  10. Carr V. Patients’ techniques for coping with schizophrenia: An exploratory study. British Journal of Medical Psychology [Internet]. 1988 Dec [cited 2023 Aug 25];61(4):339–52. Available from: https://onlinelibrary.wiley.com/doi/10.1111/j.2044-8341.1988.tb02796.x 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Nell Marquess

Bachelor of Medicine, Bachelor of Surgery - MBBS, Medicine, University of Exeter

Nell is a medical student studying at the University of Exeter with an interest in psychiatry, general practice and women’s health. She has a background in teaching and has previously worked as an editor for a student medical journal. She is now writing medical articles for Klarity alongside her studies.

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