This is not a treatise on how to diagnose schizophrenia nor on how to manage it. The assemblage of symptoms and behaviours which is likely to attract the diagnosis of schizophrenia, and the possible reasons for its existence, raise many questions. Here are some of those questions and the progress made in answering them.
- The problem with definitions of schizophrenia is that many individuals have one foot inside and one foot outside the boundaries. The individuals – like the definitions themselves – change with time.
- The range of symptoms is very wide. Some have florid hallucinations and delusions, others are blunted and emotionally flat. Depression is common, but some patients are elated.
- MRI and PET studies have suggested disturbed neural circuitry in the prefrontal regions, the thalamic nuclei and the cerebellum.
- It is clear that there is a genetic vulnerability to schizophrenia, but no-one knows its precise weighting.
- Other putative causes of schizophrenia are low levels of vitamin D in utero, and maternal infection with influenza in the second trimester. Speculations abound.