Schizophrenia (6)

Social: Living in an urban environment has been consistently found to be a risk factor for schizophrenia.[51][39] Social disadvantage has been found to be a risk factor, including poverty[52] and migration related to social adversity, racial discrimination, family dysfunction, unemployment or poor housing conditions.[53] Childhood experiences of abuse or trauma have also been implicated as risk factors for a diagnosis of schizophrenia later in life.[54][55] Parenting is not held responsible for schizophrenia but unsupportive dysfunctional relationships may contribute to an increased risk.[56][57]

Substance use: The relationship between schizophrenia and drug use is complex, meaning that a clear causal connection between drug use and schizophrenia has been difficult to tease apart. There is strong evidence that using certain drugs can trigger either the onset or relapse of schizophrenia in some people. It may also be the case, however, that people with schizophrenia use drugs to overcome negative feelings associated with both the commonly prescribed antipsychotic medication and the condition itself, where negative emotion, paranoia and anhedonia are all considered to be core features.[58] Amphetamines trigger the release of dopamine and excessive dopamine function is believed to be responsible for many symptoms of schizophrenia (known as the dopamine hypothesis of schizophrenia), amphetamines may worsen schizophrenia symptoms.[59] Schizophrenia can be triggered by heavy use of hallucinogenic or stimulant drugs.[60] One study suggests that cannabis use can contribute to psychosis, though the researchers suspected cannabis use was only a small component in a broad range of factors that can cause psychosis.[61]

Psychological: A number of psychological mechanisms have been implicated in the development and maintenance of schizophrenia. Cognitive biases that have been identified in those with a diagnosis or those at risk, especially when under stress or in confusing situations, include excessive attention to potential threats, jumping to conclusions, making external attributions, impaired reasoning about social situations and mental states, difficulty distinguishing inner speech from speech from an external source, and difficulties with early visual processing and maintaining concentration.[62][63][64][65] Some cognitive features may reflect global neurocognitive deficits in memory, attention, problem-solving, executive function or social cognition, while others may be related to particular issues and experiences.[66][56] Despite a common appearance of "blunted affect", recent findings indicate that many individuals diagnosed with schizophrenia are highly emotionally responsive, particularly to stressful or negative stimuli, and that such sensitivity may cause vulnerability to symptoms or to the disorder.[67][68][69] Some evidence suggests that the content of delusional beliefs and psychotic experiences can reflect emotional causes of the disorder, and that how a person interprets such experiences can influence symptomology.[70][71][72][73] Further evidence for the role of psychological mechanisms comes from the effects of therapies on symptoms of schizophrenia.[74]

Neural: ...

...To be continued