Explanations of schizophrenia — common mistakes

When evaluating genetic explanations, use the concordance rates from Gottesman (1991) as specific evidence. Crucially, explain why the MZ twin rate being less than 100% is a weakness of a purely genetic theory, as it proves environmental factors must also play a role.

For a top-band answer, distinguish between the original and revised dopamine hypotheses. Explain how the revised version, which incorporates hypodopaminergia, offers a more complete explanation of both positive and negative symptoms, overcoming a key limitation of the original theory.

Be careful when discussing family dysfunction. Emphasise that modern research focuses on EE as a factor in relapse, not a cause. Criticise older theories like the 'schizophrenogenic mother' for being socially sensitive and placing blame on parents, particularly mothers, without adequate evidence.

Use the correct terminology: 'metarepresentation' and 'central control'. Link each specific cognitive deficit to a specific symptom of schizophrenia (e.g., failed metarepresentation → auditory hallucinations). This demonstrates a precise and detailed understanding of the theory.

No, this is a common misconception. 'Split personality' is a colloquial term for Dissociative Identity Disorder (DID), a separate condition. The term 'schizophrenia' originates from Greek words meaning 'split mind', but this refers to a fragmentation of mental functions, such as the split between thought, emotion, and behaviour, not the presence of multiple distinct personalities.

Early theories like the 'schizophrenogenic mother' suggested this, but they are now largely discredited and considered overly simplistic and blaming. While family dynamics, such as high Expressed Emotion (EE), can be a significant source of stress and contribute to relapse, they are not seen as a direct cause. The modern consensus points towards a diathesis-stress model, where a biological vulnerability is triggered by environmental stressors, which can include the family environment.

While biological factors like genetics, dopamine imbalance, and brain structure are crucial, they do not provide a complete picture. Psychological factors (e.g., cognitive biases, family stress) and sociocultural factors (e.g., urbanicity, social isolation, discrimination) are also significant contributors. The most accepted explanation is the diathesis-stress model, which integrates biological predispositions (diathesis) with environmental and psychological triggers (stress) to explain the onset of the disorder.