Diagnosis and Classification of Schizophrenia

Diagnosis of Schizophrenia

Both the ICD (International Classification of Diseases) and the DSM (Diagnostic and Statistical Manual of Mental Disorders) provide a way to classify psychiatric disorders. It refers to grouping symptoms based on how they usually present in disorders. This classification allows for a diagnosis.

Depending on which manual a clinician or psychiatrist uses, a diagnosis and classification of schizophrenia essentially refer to a person having a mental illness affecting their thoughts, feelings, and speech, causing a loss of contact with the self and a sense of reality.

Typically, schizophrenia affects:

• People between the ages of 15 and 45.
• More men than women.
• More people in cities.
• More people from lower economic backgrounds or groups.

What is the ICD (International Classification of Diseases)?

The ICD is a classification manual used in most countries of the world (especially in Europe) to diagnose psychiatric disorders.

These revisions focus on improving the reliability and validity of the classification tool.

According to the ICD, for a patient to be diagnosed with schizophrenia:

• At least two or more of the following symptoms, with at least one from the first three:

  • Delusional perceptions, hallucinations i.e., hearing voices, disorganised thinking, incoherent speech, affective flattening, catatonic behaviours, and avolition.

The DSM is sometimes still used as the basis for the ICD.

What is the DSM (Diagnostic and Statistical Manual of Mental Disorders)?

The DSM is a classification manual similar to the ICD, though it is used primarily by American medical professionals. The American Psychiatric Association (1980) developed it and is currently in its fifth edition, which has also been revised to improve reliability and validity.

Similar to the ICD, to receive a diagnosis of schizophrenia, a patient must meet the following requirements:

• Two or more of the following symptoms for at least one month consistently, such as:

  • Delusions, hallucinations, disorganised speech – at least one of these symptoms must be present, and the following symptoms are also considered: disorganised behaviour, catatonic behaviour, affective flattening, and other negative symptoms.

  • Symptoms need to have been around for six months, with active symptoms affecting a person within one month.

Fig. 1 - Speaking with a professional can help people diagnose their mental health issues, Canva.

Now that we have discussed the classification tools, we can clarify the symptoms of schizophrenia.

What are the Symptoms of Schizophrenia?

Symptoms can be divided into two categories:

1. Positive.

2. Negative.

Here are examples of positive and negative symptoms of schizophrenia.

What are the Positive Symptoms of Schizophrenia?

Positive symptoms can be described as symptoms that add an experience for an individual. What we mean by this is that the symptom is causing an additional experience that changes a patient's perception.

For example:

• Hallucinations: A sensory experience, usually auditory or visual, although not exclusively. Patients can:

  • See distortions, such as seeing lights and patterns that are not there.

  • See objects that look like faces.

  • Hear voices outside their head that are not their own, telling them to do things.

• Delusions: Irrational beliefs and thoughts that can manifest in multiple ways:

  • Delusions of grandeur.

    A patient believes they are someone important, for instance, the next coming of Jesus.

  • Paranoia usually manifests as delusions of persecution.

    A patient may believe the government is persecuting them.

  • External control.

    A patient believes they are being controlled by something outside of themselves.

• Disorganised speech: Disjointed sentences, changing the subject in the middle of a sentence without thinking about it.

• Psychomotor disturbances: Rocking back and forth for long periods, which may alternatively manifest as catatonia (holding still for hours or days).

What are the Negative Symptoms of Schizophrenia?

Negative symptoms are the opposite of positive because they take something away from the patient. In essence, it is a loss of functioning.

Here are some examples:

• Avolition is a state of apathy in which the patient has trouble working toward or maintaining goal-directed behaviour.

  • Andreason (1982) found that avolition manifests itself primarily in poor hygiene, lack of motivation/perseverance, and lack of energy.

• Alogia (speech poverty) refers to a decrease in the quality and quantity of speech. Patients speak slower, less, and delay their responses. (If it is too disorganised, it becomes a positive symptom in the DSM-V, as mentioned above).

• Affective flattening is a lack of facial expressions and reactions.

• Anhedonia is the inability to feel positive emotions fully.

Classifying disorders allows clinicians to discuss patients and their symptoms and creates a consensus for effective, standardised treatment.

Without the guidelines in these manuals, disorders would not be formally recognised. A patient in one part of the world might receive a completely different diagnosis, and therefore different treatment than a patient in another part of the world.

Therefore, it is essential to assess the reliability and validity of the classification systems and the consistency of the diagnoses. It is also essential to understand the implications of using such a system to 'pigeonhole' patients.

Fig. 2 - Positive and negative symptoms of schizophrenia differ.

Causes of Schizophrenia

There are various arguments out there that discuss the causes of schizophrenia, and they tend to fall into two categories:

1. Biological explanations of schizophrenia
2. Psychological explanations of schizophrenia

Biological explanations for schizophrenia attribute the cause of the disorder to neural correlates, brain abnormalities, genetics, and the dopamine hypothesis.

Psychological explanations for schizophrenia focus more so on family dysfunctions and cognitive explanations.

Describe and Evaluate the Classification of Schizophrenia

It is worth briefly pointing out the general problem of using a classification system to 'label' patients with disorders, as we need to evaluate the classification and diagnosis of schizophrenia.

• Angermeyer and Matschinger (2003) surveyed adults of German nationality and found that labelling people with schizophrenia strongly negatively impacts public opinion.

Advocating the idea that schizophrenic patients are ‘dangerous' had a strong emotional impact on the way people react emotionally to someone with schizophrenia. Calling them needy led to mixed reactions.

In comparison, people with major depression were not as stigmatised in public opinion.

• Scheff (1999) also considered that mental illness labelling profoundly affected the stigmatised patients and almost created a self-fulfilling prophecy, i.e. patients began to behave as they were 'expected' to as schizophrenic or mentally ill people after being labelled.

Fig. 3 - Schizophrenia labels often come with stigma.

When two different classification systems are used, problems with reliability and validity arise in diagnosing schizophrenia. When two classification systems are used to diagnose a disorder, clinicians may not agree on a diagnosis because one manual may not list the same symptoms as another manual.

How can a person reliably diagnose schizophrenia when the ICD states to look for one set of symptoms, and the DSM states to look for a different set of prioritised symptoms?

If a person is misdiagnosed, the treatment may not be effective and address the root cause of the symptoms directly. It would be best to keep that in mind when consulting these diagnostic and classification tools.

Issues with comorbidity also exist, in that there is not enough separation between symptoms of different mental disorders.