Symptoms and Features of Schizophrenia


DSM5 requires at least two of the following symptoms, one must be delusions, hallucinations or disorganised speech/thought but the person may also have grossly disorganised or catatonic behaviour and negative symptoms, (see Stretch and Challenge).  A diagnosis of schizophrenia will not be made until the person has experienced at least one month of active symptoms and disturbance to everyday functioning for at least 6 months.


Delusions are ‘fixed beliefs that are not amenable to change in the light on conflicting evidence’ (DSM5 2013). They may relate to everyday life, (e.g. believing your movements are being monitored by the police) or ‘bizarre’ meaning they are implausible to people of from the same cultural background. Delusional beliefs take many forms, e.g. persecutory (someone is trying to harm them), referential (social and environment cues have special, personal meanings) and grandiose (the individual is exceptional or superior in some way).

Thought insertion

A common delusion that affects as many as 20% of people with schizophrenia. These people believe their thoughts do not belong to them and have been implanted by an external source. They experience a ‘blurring’ of the boundary between the self and others and feel that this border has become permeable; this can lead to the belief that thoughts, feelings and experiences can pass from one person to another.


Hallucinations are involuntary, vivid and clear perceptual experiences that occur in the absence of any external stimuli. While hallucinations can be visual, olfactory (smell) and even somato-sensory (bodily feelings), auditory hallucinations are most common in people with schizophrenia. This is often experienced as hearing voices which are distinct from one’s own inner voice/thoughts.

Disordered thinking (formal thought disorder)

Disorganised thinking is inferred from a person’s speech, which may be characterised by derailment, loose association or tangentially. They may switch from one topic to another and jumble seemingly unrelated ideas, making it difficult to follow their ‘train of thought’. Word salad refers to apparently random and incoherent stringing together of words while the term neologism refers to blended words together to create new words. Mixing up one’s words can be quite common and therefore this is only classed as symptomatic if it leads to dysfunctional communication.


The lifetime prevalence of schizophrenia is 0.3-0.7 %. This varies with ethnicity, nation and geographic origin in immigrants. Onset is slightly earlier in males (early to mid-20s) than females (late-20s). Males tend to have a poorer prognosis than females. Females are over-represented in late-onset cases (40+). Prognosis is variable and hard to predict; a minority recover completely, most suffer with chronic, episodic impairment and some show progressive deterioration, with increasingly brief periods of remission and severe cognitive deficits. Positive symptoms reduce over time but debilitating negative symptoms often remain.

Individual differences

Cultural differences in hearing voices

Tanya Luhrmann et al. (2015) interviewed 60 American, Indian and Ghanaian people with schizophrenia; 70% of the American people said their voices told them to hurt people whereas 50% of Ghanaians said the voices were mainly positive. Some said they had bad voices as well as good, but said the good voices were more powerful. Only 20% of the Ghanaian people said their voices told them to kill or fight. The Indian people tended to hear family members offering guidance and/or scolding them whereas only 10% of the American people said the voices belonged to family members.

Stretch and challenge

starsSchizophrenia is a heterogeneous syndrome with many symptoms.  In addition to those described above, some people with schizophrenia exhibit catatonic behaviour including negativism, (resistance to instructions), waxy immobility (assuming rigid, inappropriate and bizarre postures), stupor and/or mutism (a complete lack of physical or verbal responses). Others show excessive movement and/or repeat movements (echopraxia) or phrases (echolalia).  Negative symptoms including diminished emotional expression (flat affect) is common, as is avolition (lack of goal-directed behaviour) and alogia (paucity of speech).

How do you think this wide range of symptoms affects reliability and validity of diagnosis of schizophrenia?

Elise’s story

One winter’s night, university student Elise was found wandering around the campus in her nightie. Freezing cold, she whispered feverishly to herself, stopping periodically to look behind her before hurrying on. She appeared terrified and distraught. Fortunately, Elise was spotted by some other students who stopped to ask if she was okay. She stared at them, round-eyed, “two on the off-spin, two on the off-spin” she repeated, with tears rolling down her face. The students thought she might have taken drugs and rang the University Welfare Office emergency number.

Half an hour later, Elise was safe and warm in the Welfare Centre. The staff called her flat-mates to try and find out more information. They explained that Elise’s behaviour had become increasingly peculiar over the last few weeks. For example, she had started wearing two pairs of trousers, one over the top of the other. When asked why she had told them ‘people can see through me’. She had also been collecting rainwater in containers in the garden and using the water to make her tea. She had said it the water in the tap was ‘turning to acid’. Then she stopped using the electric kettle, boiling water in a pan instead. She explained that when she touched the kettle it transmitted coded messages into her brain that gave her headaches.

At first, her friends thought that she just a weird sense of humour and hoped for the best. They had also heard her opening and closing the front door over and over again in the middle of the night. They had no idea how to tackle her strange behaviour. Then one night, they had heard the front door slam. Elise’s coat still hung in the hall, but she was nowhere to be found.

Could Elise have schizophrenia? What other information would you want to find out?

Issues with the diagnosis of schizophrenia

Schizophrenia can be reliably diagnosed

One strength of the diagnosis of schizophrenia is that it can be made with a high degree of consistency and this is true of diagnoses made with both the DSM5 and ICD10.

The field trials of the DSM 5 report a kappa of 0.46 which is interpreted as ‘good’ (Regier et al. 2013) while Sartorius et al. (1995) quote a very high kappa of 0.86, with only 3.8% of clinicians  saying that they lacked confidence in their diagnoses of schizophrenia using ICD10.

This is important because it suggests that the descriptors for schizophrenia are sufficiently detailed to allow clinicians to distinguish this condition from others with shared symptoms and features.

Competing argument This said, diagnosing schizophrenia is not easy, as it shares symptoms with various other disorders. For example, hallucinations can be experienced by people with depression, mania and post-traumatic stress disorder and can be caused by drug withdrawal, metabolic disorders, stress and sleep deprivation while catatonic behaviour can be symptomatic of depression or bi-polar disorder.

Cultural differences can make diagnosis difficult

One problem with identifying disordered thinking is that this can be difficult if the patient is from a different cultural background to the psychiatrist

For example, Rastafarians often use neologisms (new words) which are a play on English words such as “overstand” for “understand”, “downpress” for “oppress”,“ I-ditate” for “meditate” and a psychiatrist who was unware of these conventions may see this as a sign of disorganised thinking.

This demonstrates that an accurate diagnosis of schizophrenia requires an awareness and sensitivity to cultural and linguistic differences.

Practice Questions

  1. Describe two symptoms of schizophrenia (4)
  2. Explain one issue with the diagnosis of schizophrenia (3)
  3. Beryl sometimes gets up several times in the night. Her neighbour Violet can see her peering out of the front door before shouting angrily into the night. Violet thinks Beryl might have schizophrenia. Discuss Violet’s concerns with reference to the symptoms and features of schizophrenia (8).
  4. To want extent is the diagnosis of schizophrenia valid and reliable? (20)