The greatest risk factor for developing schizophrenia is having a first-degree relative with the disease (risk is 6.5%); more than 40% of identical twins of those with schizophrenia are also affected. If one parent is affected the risk is about 13% and if both are affected the risk is nearly 50%. However, the DSM-5 indicates that most people with schizophrenia have no family history of psychosis. Results of candidate gene studies of schizophrenia have generally failed to find consistent associations, and the genetic loci identified by genome-wide association studies explain only a small fraction of the variation in the disease.Many genes are known to be involved in schizophrenia, each with small effect and unknown transmission and expression. The summation of these effect sizes into a polygenic risk score can explain at least 7% of the variability in liability for schizophrenia. Around 5% of cases of schizophrenia are understood to be at least partially attributable to rare copy number variations (CNVs); these structural variations are associated with known genomic disorders involving deletions at 22q11.2 (DiGeorge syndrome) and 17q12 (17q12 microdeletion syndrome), duplications at 16p11.2 (most frequently found) and deletions at 15q11.2 (Burnside–Butler syndrome). Some of these CNVs increase the risk of developing schizophrenia by as much as 20-fold, and are frequently comorbid with autism and intellectual disabilities.The genes CRHR1 and CRHBP are associated with the severity of suicidal behavior. These genes code for stress response proteins needed in the control of the HPA axis, and their interaction can affect this axis.
The timing of delivery should balance the desire for optimal outcomes for the baby while reducing risks for the mother. The severity of disease and the maturity of the baby are primary considerations. These considerations are situation-specific and management will vary with situation, location, and institution. Treatment can range from expectant management to expedited delivery by induction of labor or Caesarean section, in addition to medications. Important in management is the assessment of the mothers organ systems, management of severe hypertension, and prevention and treatment of eclamptic seizures. Separate interventions directed at the baby may also be necessary. Bed rest has not been found to be useful and is thus not routinely recommended. Blood pressure
The World Health Organization recommends that women with severe hypertension during pregnancy should receive treatment with anti-hypertensive agents. Severe hypertension is generally considered systolic BP of at least 160 or diastolic BP of at least 110. Evidence does not support the use of one anti-hypertensive over another. The choice of which agent to use should be based on the prescribing clinicians experience with a particular agent, its cost, and its availability. Diuretics are not recommended for prevention of pre-eclampsia and its complications. Labetalol, hydralazine and nifedipine are commonly used antihypertensive agents for hypertension in pregnancy. ACE inhibitors and angiotensin receptor blockers are contraindicated as they affect fetal development.The goal of treatment of severe hypertension in pregnancy is to prevent cardiovascular, kidney, and cerebrovascular complications.