psychiatric disorders
Schizophrenia
Etiology of Schizophrenia
Although its specific causes and mechanisms are unknown, schizophrenia has a biologic basis, as evidenced by Alterations in brain structure (eg, enlarged cerebral ventricles, thinning of the cortex, decreased size of the anterior hippocampus and other brain regions) Changes in neurochemistry, especially altered activity in markers ofdopamineand glutamate transmission Recently demonstrated genetic risk factors ( Etiology reference ) Some experts suggest that schizophrenia occurs more frequently in people with neurodevelopmental vulnerabilities and that the onset, remission, and recurrence of symptoms are the result of interactions between these enduring vulnerabilities and environmental stressors. Although schizophrenia rarely manifests in early childhood, childhood factors influence disease onset in adulthood. These factors include Genetic predisposition Intrauterine, birth, or postnatal complications Viral central nervous system infections Childhood trauma and neglect Although many people with schizophrenia do not have a family history, genetic factors are strongly implicated. People who have a 1st-degree relative with schizophrenia have about a 10 to 12% risk of developing the disorder, compared with a 1% risk among the general population. Monozygotic twins have a concordance of about 45%. 2500 g, Hemolytic Disease of the Fetus and Neonate during a 2nd pregnancy, and hypoxia increase risk. Neurobiologic and neuropsychiatric tests suggest that aberrant smooth-pursuit eye tracking, impaired cognition and attention, and deficient sensory gating occur more commonly among patients with schizophrenia than among the general population. These findings also can occur among 1st-degree relatives of people with schizophrenia, and indeed in patients with many other psychotic disorders, and may represent an inherited component of vulnerability. The commonality of these findings across psychotic disorders suggests that our conventional diagnostic categories do not reflect underlying biologic distinctions among psychoses ( Etiology reference ). Environmental stressors can trigger the emergence or recurrence of psychotic symptoms in vulnerable people. Stressors may be primarily pharmacologic (eg, Overview of Substance Use , especially Protective factors that may mitigate the effect of stress on symptom formation or exacerbation include strong psychosocial support, well-developed coping skills, and Treatment . 1.Schizophrenia Working Group of the Psychiatric Genomics Consortium: Biological insights from 108 schizophrenia-associated genetic loci.Nature511(7510):421-427, 2014. doi: 10.1038/nature13595 