It seems several bio-psycho-social factors are involved.
- Structural and functional abnormalities in the brain:
- ~ Enlarged ventricles and reduced tissue volume.
- ~ Hypofrontality (less active frontal lobes).
- ~ Diffuse neurobiological disregulation.
Schizophrenia has been characterised in part by debilitating cognitive impairments - attention, working memory and executive function.
- Dopamine hypothesis:
- ~ Drugs that increase dopamine result in schizophrenic-like behaviour (e.g. amphetamines, L-dopa - a Parkinson's treatment)
- ~ Drugs that reduce dopamine reduce schizophrenia-like behaviour (neuroleptics produce Parkinson's-like effects - insufficient dopamine)
- ~ Problematic and overly simplistic: many not helped by neuroleptics, symptoms subside more slowly than anticipated, neuroleptics only really affect positive symptoms.
- ~ Current theory emphasises at least 3 neurochemical abnormalities (see next).
- 3 specific neurochemical abnormalities:
- ~ Excessive stimulation of striatal dopamine (movement, balance)
- ~ Deficient stimulation of prefrontal dopamine (thinking and reasoning)
- ~ Deficit in glutamate or blocking of NMDA sites.
Stress may activate underlying vulnerability and increase risk of relapse.
Families show ineffective communication. High expressed emotion --> relapse.
Healthy, supportive homes may be a protective factor.