<unk>  is a psychiatric diagnosis that describes a mental disorder characterized by impairments in the perception or expression of reality and by significant social or occupational dysfunction.
The causes of<unk>  have been the subject of much debate over many decades with various factors proposed and discounted. To date none has been fully elucidated, but evidence suggests that genetic vulnerability and environmental stressors act in combination to result in<unk> .
Studies suggest that genetics, early environment, neurobiology and psychological and social processes are important contributory factors. Current psychiatric research into the development of the disorder often focuses on the role of neurobiology, although a reliable and identifiable organic cause has not been found. In the absence of a confirmed specific pathology underlying the diagnosis, some question the legitimacy of<unk> 's status as a disease. Furthermore, some propose that the perceptions and feelings involved are meaningful and do not necessarily involve impairment. Although no common cause of<unk>  has been identified in all individuals diagnosed with the condition, currently most researchers and clinicians believe it results from a combination of both brain vulnerabilities (either inherited or acquired) and stressful life-events. This widely-adopted approach is known as the 'stress-vulnerability' model, and much scientific debate now focuses on how much each of these factors contributes to the development and maintenance of<unk> .
It is also thought that processes in early neurodevelopment are important, particularly prenatal processes. In adult life, importance has been placed upon the function (or malfunction) of dopamine in the mesolimbic pathway in the brain. This theory, known as the dopamine hypothesis of<unk>  largely resulted from the accidental finding that a drug group which blocks dopamine function, known as the phenothiazines, reduced psychotic symptoms. However, this theory is now thought to be overly simplistic as a complete explanation. These drugs have now been developed further and antipsychotic medication is commonly used as a first-line treatment. Although effective in many cases, these medications are not well tolerated by some patients due to significant side-effects. The positive symptoms are more responsive to medications; negative symptoms being less so.
Differences in brain structure have been found between people with<unk>  and those without. However, these tend only to be reliable on the group level and, due to the significant variability between individuals, may not be reliably present in any particular individual. Significant brain atrophy and enlarged ventricles are the most conspicuous of such differences.
Schizophrenia causes
Personality disorder causes
Bipolar disorder causes
Delirium causes
Mental retardation risk factors
Mental retardation causes
Amnesia causes
Delusional disorder causes