Diagnosis of Schizophrenia

Diagnosis of Schizophrenia


Schizophrenia is a complex set of symptoms that affects roughly 1% of the population. It affects men more than it does women and is likely to be diagnosed by the time they are in their early 20s and early 30s respectively. There are two main systems used to classify and diagnose schizophrenia. These are the DSM and ICD.

The DSM states that at least one positive symptom is needed for a diagnosis of schizophrenia whereas, the ICD states that 2 negative symptoms are sufficient for a diagnosis. The ICD also identifies subtypes such as paranoid schizophrenia, but this has been dropped in the DCM.

Positive Symptoms

A positive symptom is one that adds something to the experiences of the sufferer. There are three main positive symptoms:

Hallucinations – These are unusual sensory experiences and could have no relation to the current events or environment the person is in. These can be experienced through any sense for example seeing imaginary things or hearing voices to smelling something or feelings such as being scratched.

Delusions – These are irrational beliefs, often seen as paranoia. They can also have delusions when they believe they are important figures through time for example someone believing they are a military leader such as Napoleon Bonaparte. They may also believe that they are under someone else control and may commit random acts on their behalf. Although rare, this can lead to aggression as they believe they are acting on the orders of someone else or feel like they are being followed with the paranoia.

Speech Disorganisation – This involves the individual producing incoherent speech and jumping mid conversation.

Negative Symptoms

A negative system is one that removes some basic behaviours or basic skills from the sufferer.

Avolition – This is characterised by lack of motivation and activity levels. Andreason (1982) Identified 3 key areas such as hygiene and grooming, effort in education/work and lack of energy.

Speech Poverty – This is the reduction of amount and quality of speech and can present itself as a delay in response.


Validity and reliability

As there are two different models to classify and diagnose schizophrenia there is a possibility of receiving a diagnosis of schizophrenia under one model and not the other.

Cheniaux et al. (2009) had two psychologists diagnose 100 patients using both DSM and the ICD criteria. One doctor diagnosed 26 with the DSM and 44 with ICD and the other 13 vs 24. Therefore, we have to question the validity of each method of classification as they have poor inter-rater reliability.


Co-morbidity is when patients are diagnosed with more than one condition. This can cause us to question the validity of the diagnosis criteria. We must ask ourselves are they sperate conditions or should they lead to a single diagnosis.

Buckley et al. (2009) looked at patients with a diagnosis of schizophrenia and other conditions for the co-morbidity rate. He found that out of those with a diagnosis of schizophrenia, 50% also had Depression, 29% suffered with PTSD and 23% had a diagnosis OCD. For those in the medical field, this questions if the need to consider if they are treating each diagnosis separately or as a single condition.

Symptom Overlap

Diagnosis mental health issues can very difficult due to disorders often having similar symptoms. Bipolar disease shares with schizophrenia symptoms such as delusions and avolition, these questions the validity of a diagnosis as there is an inconsistent criterion. A Patient may get a diagnosis of schizophrenia under the ICD and one patient receive a diagnosis bipolar disorder with DCM even if they show the same symptoms. These diagnoses will affect the treatment a patient gets so could be significant in the impact of their quality of life.

Gender Bias

There may be some gender bias when we consider the diagnosis of schizophrenia as men are consistently diagnosed with schizophrenia more than women. However, this could be due to a genetic factor that is yet to be investigated. Cotton et al. (2009) stated that women in society often functioned better than men, so they showed to have better relationships and more likely to work. This could lead to an under diagnosis in women because their symptoms are masked by their positive interpersonal skills.

Cultural Bias

African American and Afro-Caribbean populations are more likely to receive a diagnosis of schizophrenia but the rates in Africa and West Indies are no higher than elsewhere. This is likely due to cultural bias. In some cultural, hearing voices and talking to the dead is considered “normal” but in western society this could lead to a diagnosis of schizophrenia. Therefore, it is difficult to generalise the rate of schizophrenia across cultures that made lead to an understanding of the development and/or treatment of the condition. There may also be influence of racial discrimination when diagnosis schizophrenia. This is supported by Escobar (2012) as he stated that white psychiatrists would over-interpret symptoms and distrust honesty of black patients.