Cognitive Explanations of Schizophrenia

- Malfunctions in cognitive systems = internal mental processes. Systems include perception; attention; working memory & thinking / decision-making. - Has yet to explain all symptoms & behaviours of schizophrenia.

- 2.5-4% of general population have experienced hallucinations; most do not have psychiatric problems. - Triggers such as sleep deprivation cause individuals to experience hallucinations. Annotation identifies environmental triggers & suggests sleep deprivation may switch on dormant genes. - Voices attributed to sinister origins -> social withdrawal / self-harm -> continuing cycle of sleep deprivation -> voices -> social isolation / harm.

- Individuals endorse dysfunctional beliefs about performance & ability to seek pleasure; also have a cynical view of future. - Negative views; negative views about oneself & negative views about future = linked in a cycle. - Only experiencing negative internal messages -> negative symptoms such as flatness of affect; avolition & anhedonia.

- All information received from senses. - Difficulties inhibiting preconscious content -> difficulties selecting correct information to process & carrying through an appropriate response.

- Individuals with schizophrenia have a compromised theory of mind; experience disorders of willed action; self-monitoring & monitoring other people's thoughts / intentions. - Negative & disorganised symptoms. - Delusions of alien control & vocal hallucinations. - Delusions of persecution.

- Empirical evidence supports presence of cognitive & attentional impairments in schizophrenia. - Compared Stroop-test performance between individuals with & without schizophrenia. Participants with schizophrenia were significantly slower & made more mistakes. - Provide evidence that individuals with schizophrenia struggle to filter information effectively because cognitive filtering mechanisms are defective. Supports information-processing deficits underlying schizophrenia.

- Accounts for cognitive-processing issues & certain symptoms but fails to explain all symptoms & behaviours. Not a comprehensive theory on its own. - Motor issues & movement abnormalities are not well explained by cognitive models. Models also fail to fully explain underlying origins of cognitive deficits themselves. - Explaining some processing difficulties does not explain entire disorder or origins of those difficulties -> cognitive approach insufficient as a singular explanation for schizophrenia.

- Attempts to ground cognitive causal explanations in biology can reduce schizophrenia to brain dysfunction. - Proposed faulty cognitive mechanisms stem from disconnection of functions between frontal cortex & posterior brain regions; noted changes in cerebral blood flow during cognitive tasks. - Critics argue reducing a complex human experience entirely to brain dysfunction or internal cognitive-processing errors remains reductionist. Biological grounding does not remove this limitation.

- To address theoretical; methodological & reductionist limits of cognitive explanations -> place cognitive processes within a more holistic framework. - Genetic vulnerabilities or early-life factors + social stressors -> provoke dopamine receptors into releasing dopamine -> dopamine surge causes downstream cognitive-processing problems -> hallucinations & delusions -> further increased stress. - Cognitive difficulties form part of an interacting cycle involving vulnerability; social stress & dopamine. Cognitive explanation most effective when integrated into a more holistic framework.