Classification of schizophrenia


Schizophrenia- a severe mental illness where contact with reality and insight are impaired, an example of psychosis.

  • Schizophrenia has a cluster of symptoms that appear to be unrelated.

  • It is classified by in the ICD-10 (International Classification of Disease) and the DSM-5 (Diagnostic and Statistical Manual).

  • In the DCM-5 one of the positive symptoms such as delusions, hallucinations or speech disorganisation must be present for there to be a diagnosis.

Whereas with the ICD two or more negative symptoms are sufficient.

1 of 25


Positive symptoms

  • Additional experiences beyond those of ordinary experience.


Unusual sensory experience. Some hallucinations are related to events in the environment whereas others bear no relationship to what the senses are picking up from the environment, e.g, voices heard.


Also known as paranoia. Irrational beliefs that make sense to the sufferer but seem bizarre to others.

2 of 25


Negative symptoms

  • Loss of usual abilities.


Finding it difficult to begin or keep up with goal directed activities. Andreason- poor hygiene/grooming, lack of persistence in work/education, and lack of energy.

Speech poverty-

Reduction in the amount and quality of speech. Delay in the suffers verbal responses during conversation.

3 of 25



Reliability- Inter-rater reliability, where two assessors agree on their diagnosis. Cheniaux- 2 independent assessors assess 100 patients using both DCM and ICD. Inter-rater reliability was poor, weakness of diagnosis of schizophrenia.

 Co-morbidity- The phenomenon that two or more conditions occur together.

Patients diagnosed with schizophrenia were often also diagnosed with depression or substance abuse. In terms of diagnosis is may mean that we are bad at differentiating between the two conditions, in terms of classification it may mean that they might be better seen as a single condition.

Gender bias in diagnosis

Men have been diagnosed with schizophrenia more often than women. This could be due to female patients functioning better than men, more likely to work and have good family relationships. High functioning might explain why some women have not been diagnosed with schizophrenia whereas men with similar symptoms might have been.

Raises questions over the validity of diagnosis.

4 of 25

Biological explanations

Genetic basis

Schizophrenia runs in families- strong relationship between the degree of genetic similarity and shared risk of schizophrenia.

Candidate genes:

There are a few genes attributed to schizophrenia. However, Schizophrenia is polygenic, it requires a number of factors to work in combination- diathesis- stress model.

The effects of genetics have been measured using family studies, twin studies and adoption studies.

5 of 25

Biological explanations


Gottesman- Found schizophrenia was more common among biological relatives. The closer the relation the higher the risk. Children with 2 schizophrenic parents had a concordance rate of 46%, which went down to 13% when only 1 parent had schizophrenia.

Twin studies

Tiernari- MZ twins had 40% concordance, whereas DZ twins had 7% concordance. Presents strong argument that genes influence the onset of schizophrenia.

6 of 25

Biological explanations

The Dopamine hypothesis

Neurotransmitters- brains chemical messengers work differently in the brain of a schizophrenic, in particular dopamine. Dopamine is important in the functioning of several brain systems that may be implicated in the symptoms of schizophrenia.

Hyperdopaminergia in the subcortex- high levels or activity of dopamine in the subcortex (central areas of the brain).

An excess of dopamine in Broca’s area (speech production) can be associated with speech poverty and/or auditory hallucinations.

Hypodopaminergia in the cortex- abnormal dopamine systems in the brain’s cortex. Low levels of dopamine in the pre-frontal cortex (decision making and thinking) have a role in negative symptoms of schizophrenia.

7 of 25

Biological explanations

Neural correlates of schizophrenia

Measurements of the structure or function of the brain that correlate with schizophrenia. Both positive and negative symptoms have neural correlates.

Neural correlates of negative symptoms- Avolition involves the loss of motivation, which anticipates a reward. Certain part of the brain, such as the ventral striatum are involved in this anticipation. Therefore, abnormality in areas like the ventral striatum may be involved in the development of avolition. Negative correlation between activity levels in the ventral striatum and severity of negative symptoms.

Neural correlates of positive symptoms- Control and non-control (suffering from hallucinations) groups were asked to identify if recordings were their voices or not. Then had brain scans. Lower activation levels in the superior temporal gyrus and anterior cingulate gyrus were found in the hallucination group. Reduced activity in these areas is a neural correlate of auditory hallucinations.

8 of 25

Biological explanations


Multiple sources- Strong evidence such as the Gottesman study and numerous adoption and twin studies. However, the evidence does not mean that schizophrenia is entirely genetic.

Mixed evidence- Amphetamine’s increase the levels of dopamine and make schizophrenia worse and antipsychotic drugs work by reducing dopamine activity. Both kinds of drug suggest an important role for dopamine in schizophrenia.

Dopamine is an important factor in schizophrenia, however so are other neurotransmitters. Therefore, evidence can be described as mixed.

Correlation-causation problem- Evidence leaves questions unanswered. Does the unusual activity in the areas of the brain cause the schizophrenia? The existence in neural correlates in schizophrenia therefore tells us relatively little in itself.

9 of 25

Biological therapies: drug therapy

Antipsychotics can be taken in the form of tablet or syrup. Those at risk of not taking their medication can be given an injection every 2-4 weeks. They can be given short term or some sufferers may be given them for the rest of their lives. There are two types of antipsychotics:

Typical antipsychotics

  • Been used since the 1950s, inc. chlorpromazine.

  • Strong association between the use of typical antipsychotics and the dopamine hypothesis.

  • They work by acting as antagonists (reduce the action of the neurotransmitter) in the dopamine system.

  • Chlorpromazine is also an effective sedative, so is used in syrup form for when patients are first admitted if they are anxious.

10 of 25

Biological therapies: drug therapy

How typical antipsychotics work:

1. Dopamine antagonists block dopamine receptors in the synapses of the brain.

2. Dopamine levels build up, but then production is reduced.

3. Normalised neurotransmission in key areas of the brain, reduces symptoms like hallucinations.

11 of 25

Biological therapies: drug therapy

Atypical antipsychotics

  • Been used since the 1970s, the aim was to maintain/improve the effectiveness of the drugs in supressing the symptoms whilst also minimising the side-effects.

  • Clozapine was withdrawn during the 1970s following deaths of patients due to a blood condition. However, it was re-introduced when it was found to be more effective than typical antipsychotics, so was marketed as a treatment to be used when all else failed.

  • Due to its potentially fatal side-effects it cannot be administered via injection and can only be given in small oral doses.


12 of 25

Biological therapies: drug therapy

Clopazine works in the same way as chlorpromazine but is believed to act on serotonin and glutamate receptors which helps to improve mood and reduce depression and anxiety in patients, and improve cognitive functioning.

Sometimes prescribed when a patient is at a high risk of suicide due to its mood-enhancing properties. 30-50% of sufferers of schizophrenia attempt suicide at some point.

  • Risperidone was developed in the 1990s to work in the same way as clopazine without the serious side effects.

  • It binds more strongly to dopamine receptors so can be taken in smaller doses than other typical and atypical antipsychotics.

13 of 25

Biological explanations: drug therapy


Evidence for effectiveness- Large body of evidence to support that both types of antipsychotics are at least moderately effective in tackling the symptoms of schizophrenia.

Meltzer- Clopazine is effective in 30-50% of treatment-resistant cases where other antipsychotics have failed.

Serious side effects- Stiff jaw, weight gain, agitation etc to more fatal such as NMS and tardive dyskinesia (dopamine super-sensitivity leading to involuntary facial movements).

Atypical antipsychotics were developed to reduce the frequency of serious side effects and generally this has succeeded. However, side effects still exist and patients taking Clopazine have to have regular blood tests.

Side effects are thus still a significant weakness of antipsychotic drugs.

Human rights abuse argument- Antipsychotic drugs have been widely used in hospital situations to calm patients down and make them easier for staff to work with, rather for the benefits for the patients themselves. Although short-term use of the drugs to calm patients is recommended, it has been argued by some that this is a human rights abuse.

14 of 25

Psychological explanations for schizophrenia

Family dysfunction

The schizophrenogenic mother- Fromm-Reichmann

Cold, rejecting and controlling mother that creates a tense family climate. Leads to distrust that later develops into paranoid delusions (belief that one is getting persecuted by another), and ultimately schizophrenia.

Expressed emotion

Level of emotion expressed, particularly negative, towards a patient with schizophrenia.

  • Verbal criticism of the patient, may be with violence.

  • Hostility, anger or rejection

  • Emotional over-involvement, inc. needless self-sacrifice.

Serious source of stress for the schizophrenia sufferer. Explains relapse in patients. Source of stress can trigger an already vulnerable patient- diathesis-stress model.

15 of 25

Psychological explanations for schizophrenia

Cognitive explanations

Role of mental processes. Associated with abnormal information processing- can be an explanation for schizophrenia.

  • Reduced information processing in the ventral striatum associated with the negative symptoms.

  • Reduced processing in the cingulate and temporal gyri associated with hallucinations.

 Frith et al identified two kinds of dysfunctional thought processes that could underlie some symptoms:

  • Metarepresentation- cognitive ability to reflect on thoughts and behaviour. Insight into our own intentions and goals. Interpret others actions. Dysfunction in metarepresentation would disrupt ability to recognize our own actions and thoughts as being carried out by ourselves not someone else. Explains hallucinations and delusions.

  • Central control – ability to suppress automatic responses and perform deliberate actions instead. Disorganised speech and thought disorder could be the result of not being able to suppress automatic thoughts and speech triggered by other thoughts.

16 of 25

Pyschological explanations


Parent-blaming- Parents who have already suffered at seeing their child descend into a schizophrenic, and will bear lifelong responsibility for their care. Parent go through further trauma by receiving the blame.

Supports diathesis -stress modelSchizophrenia is associated with abnormal information processes, and can be used to explain it. Characterised by disruption to normal though processing.

  • Reduced processing in the ventral striatum is associated with negative symptoms.

  • Reduced processing of information in the temporal and cingulate gyri are associated with hallucinations.

Stroop test- Compared schizophrenics with controls on a range of cognitive tasks inc. the Stroop test. Schizophrenics took over twice as long to identify the colours than the control group.

17 of 25

Psychological therapies

CBT and family therapies are used for the treatment of schizophrenia. Token economies are used for the management of schizophrenia.

Cognitive behaviour therapy

  • Between 5-20 sessions, either in groups of individual.

  • Helps patients identify irrational thoughts and seeks to change them.

  • Patients can be helped to see how their delusions and hallucinations impact on their feelings and behaviour, understanding where symptoms come from can be helpful for patients.

  • Offering psychological explanations for delusions and hallucinations can help reduce the patient’s anxiety.

  • Delusions are also challenged so that the patient learns that their beliefs are not based on reality.

18 of 25

Psychological therapies

Family therapy

  • Aims to improve quality of communication and interaction between patients and family members.

  • Most psychologists are concerned with reducing stress within the family that may contribute to the patients chance of relapse.

  • Family therapy aims to reduce levels expressed emotion.

How family therapy helps:

  • Forms a therapeutic alliance with family members.

  • Reduces the stress of caring for a relative with schizophrenia.

  • Reduces anger and guilt in family members.

  • Increases the chance of patient complying with medication.

Overall reduces chance of relapse and re-admission.

19 of 25

Psychological therapies

Token economies

Reward systems used to manage behaviour of people with schizophrenia, in particular those who have spent long periods in psychiatric hospitals (institutionalised).

  • Modifies bad habits such as not brushing hair or staying in pyjamas all day.

  • Does not cure schizophrenia but improves the patient’s quality of life living outside of the hospital setting.

Tokens- given immediately to patients for good behaviour to be reinforced. Immediacy of reward is important as it prevents ‘delay discounting’, reduced effect of delayed reward.

Rewards- Based on operant conditioning. Tokens are secondary reinforcers because they only have value once the patient has learnt that they can be used to obtain rewards such as sweets, cigarettes or magazines, or in form of a service e.g. room cleaned or walk outside the hospital.

20 of 25

Psychological therapies


Evidence for effectiveness        

There is only modest support for the effectiveness of psychological treatments and schizophrenia remains one of the harder mental health problems to treat.

Treatments improve quality of life but do not cure

All psychological treatments for schizophrenia aim to make it more manageable and in some way improve the patient’s quality of life, but should not be confused with curing schizophrenia.

Ethical issues

Privileges are given more to patients with mild symptoms as it is easier for them to comply with desirable behaviours. This means that the most severely ill patients suffer discrimination, and some family members have challenged the legality of this, in turn has reduced the use of tokens in the psychiatric system.

21 of 25

Interactionist approach to schizophrenia

Interactionist approach acknowledges that there are biological, psychological and societal factors that contribute to schizophrenia.

Explaining the interactionist approach: the diathesis stress model

Vulnerability (diathesis) + psychological trigger (stress) = schizophrenia

Meehl’s model

·         Original diathesis stress-model.

·         Diathesis was entirely genetic, the result of a single ‘schizogene’.

·         Without the schizogene no amount of stress could result in schizophrenia.

22 of 25

Interactionist approach to schizophrenia

The modern understanding of diathesis

·         There is not one single ‘schizogene’; there are many.

·         Diathesis ranges beyond genetics, it can also include psychological trauma.

·         Trauma becomes the diathesis rather than the stressor­ – Read- neurodevelopmental model that proposes early trauma alters the developing brain (e.g. child abuse)

The modern understanding of stress

·         Stress was seen as psychological in nature, in particular parenting.

·         Modern definition of stress (in relation to diathesis-stress) now includes anything that risks triggering schizophrenia.

·         Cannabis is now a stressor as it increases the risk of schizophrenia by up to seven times.

23 of 25

Interactionist approach to schizophrenia

Treatment according to the interactionist model

Because it acknowledges both biological and psychological factors both biological and psychological treatments are compatible.

The model combines both antipsychotic medication and psychological therapies, e.g. CBT.

24 of 25

Interactionist approach to schizophrenia


Evidence for the role of vulnerability and triggers

Tiernari et al- genetically vulnerable (adopted) children more sensitive to parenting style.

The original diathesis-stress model is over-simple

There is not a single schizogene and stress is now known to come in multiple forms, e.g. cannabis use, not just parenting style or dysfunctional family.

Support for the effectiveness of combinations of treatments

Turkington- it is not possible to use combination treatments without adopting an interactionist approach.

Studies with patients combining both treatments compared to 1 showed lower symptom levels.

Shows there is a practical advantage to adopting an interactionist approach in the form of superior treatment outcomes.

25 of 25


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Schizophrenia resources »