Social withdrawal, sloppiness of dress and hygiene, and loss of motivation and judgment are all common in schizophrenia.Distortions of self-experience such as feeling as if one's thoughts or feelings are not really one's own to believing thoughts are being inserted into one's mind, sometimes termed passivity phenomena, are also common.The extent of the cognitive deficits someone experiences is a predictor of how functional they will be, the quality of occupational performance, and how successful they will be in maintaining treatment.
The greatest single risk factor for developing schizophrenia is having a first-degree relative with the disease (risk is 6.5%); more than 40% of monozygotic twins of those with schizophrenia are also affected.
There is a genetic relation between the common variants which cause schizophrenia and bipolar disorder, an inverse genetic correlation with intelligence and no genetic correlation with immune disorders.
They commonly include flat expressions or little emotion, poverty of speech, inability to experience pleasure, lack of desire to form relationships, and lack of motivation.
Negative symptoms appear to contribute more to poor quality of life, functional ability, and the burden on others than positive symptoms do.
Both working memory tasks and gamma oscillations are impaired in schizophrenia, which may reflect abnormal interneuron functionality.
Deficits in executive functions, such as planning, inhibition, and working memory, are pervasive in schizophrenia.However, a large body of evidence suggests that hedonic responses are intact in schizophrenia, Overall, a failure of online maintenance and reward associativity is thought to lead to impairment in the generation of cognition and behavior required to obtain rewards, despite normal hedonic responses.Both hallucinations and delusions have been suggested to reflect improper encoding of prior expectations, thereby causing expectation to excessively influence sensory perception and the formation of beliefs.Efforts to improve learning ability in people with schizophrenia using a high- versus low-reward condition and an instruction-absent or instruction-present condition revealed that increasing reward leads to poorer performance while providing instruction leads to improved performance, highlighting that some treatments may exist to increase cognitive performance.Training people with schizophrenia to alter their thinking, attention, and language behaviors by verbalizing tasks, engaging in cognitive rehearsal, giving self-instructions, giving coping statements to the self to handle failure, and providing self-reinforcement for success, significantly improves performance on recall tasks.The validity of the positive and negative construct has been challenged by factor analysis studies observing a three dimension grouping of symptoms.Different terminology is used, but a dimension for hallucinations, a dimension for disorganization, and a dimension for negative symptoms are usually described.Although these functions are dissociable, their dysfunction in schizophrenia may reflect an underlying deficit in the ability to represent goal related information in working memory, and to utilize this to direct cognition and behavior.These impairments have been linked to a number of neuroimaging and neuropathological abnormalities.A subgroup of persons with schizophrenia present an immune response to gluten different from that found in people with celiac, with elevated levels of certain serum biomarkers of gluten sensitivity such as anti-gliadin Ig G or anti-gliadin Ig A antibodies.Abnormal dopamine signalling has been implicated in schizophrenia based on the usefulness of medications that effect the dopamine receptor and the observation that dopamine levels are increased during acute psychosis.