Currently, all treatments for schizophrenia (SCZ) function primarily by blocking D(2)-type dopamine receptors. Given the limitations of these medications, substantial efforts have been made to identify alternative neurochemical targets for treatment development in SCZ. One such target is brain glutamate. The objective of this article is to review and synthesize the proton magnetic resonance spectroscopy ((1)H MRS) and positron emission tomography (PET)/single-photon emission computed tomography (SPECT) investigations that have examined glutamatergic indices in SCZ, including those of modulatory compounds such as glutathione (GSH) and glycine, as well as data from ketamine challenge studies. The reviewed (1)H MRS and PET/SPECT studies support the theory of hypofunction of the N-methyl-D-aspartate receptor (NMDAR) in SCZ, as well as the convergence between the dopamine and glutamate models of SCZ. We also review several advances in MRS and PET technologies that have opened the door for new opportunities to investigate the glutamate system in SCZ and discuss some ways in which these imaging tools can be used to facilitate a greater understanding of the glutamate system in SCZ and the successful and efficient development of new glutamate-based treatments for SCZ.
The last fifteen years have seen a great increase in our understanding of the role of glutamate in schizophrenia (SCZ). The glutamate hypothesis focuses on disturbances in brain glutamatergic pathways and impairment in signaling at glutamate receptors. Proton Magnetic Resonance Spectroscopy (1H-MRS) is an MR-based technique that affords investigators the ability to study glutamate function by measuring in vivo glutamatergic indices in the brains of individuals with SCZ. 1H-MRS studies have been performed comparing glutamatergic levels of individuals with SCZ and healthy control subjects or studying the effect of antipsychotic medications on glutamatergic levels. In this article we summarize the results of these studies by brain region. We will review the contribution of 1H-MRS studies to our knowledge about glutamatergic abnormalities in the brains of individuals with SCZ and discuss the implications for future research and clinical care.
Lithium is an effective treatment in pregnancy and postpartum for the prevention of relapse in bipolar disorder. However, lithium has also been associated with risks during pregnancy for both the mother and the unborn child. Recent large studies have confirmed the association between first trimester lithium exposure and an increased risk of congenital malformations. Importantly, the risk estimates from these studies are lower than previously reported. Tapering of lithium during the first trimester could be considered but should be weighed against the risks of relapse. There seems to be no association between lithium use and pregnancy or delivery related outcomes, but more research is needed to be more conclusive. When lithium is prescribed during pregnancy, lithium blood levels should be monitored more frequently than outside of pregnancy and preferably weekly in the third trimester. We recommend a high-resolution ultrasound with fetal anomaly scanning at 20 weeks. Ideally, delivery should take place in a specialised hospital where psychiatric and obstetric care for the mother is provided and neonatal evaluation and monitoring of the child can take place immediately after birth. When lithium is discontinued during pregnancy, lithium could be restarted immediately after delivery as strategy for relapse prevention postpartum. Given the very high risk of relapse in the postpartum period, a high target therapeutic lithium level is recommended. Most clinical guidelines discourage breastfeeding in women treated with lithium. It is highly important that clinicians inform and advise women about the risks and benefits of remaining on lithium in pregnancy, if possible preconceptionally. In this narrative review we provide an up-to-date overview of the literature on lithium use during pregnancy and after delivery leading to clinical recommendations.
Lithium and antipsychotics are often prescribed to treat bipolar disorder or psychotic disorders in women of childbearing age. Little is known about the consequences of these medications during pregnancy for the developing child. The objective of this article is to systematically review findings from preclinical and clinical studies that have examined the neurodevelopmental consequences of intrauterine exposure to lithium and antipsychotics. A systematic search was performed in Embase, Medline, Web of Science, PsychINFO, Cochrane, and Google Scholar. Clinical and experimental studies were selected if they investigated neurodevelopment of offspring exposed to lithium or antipsychotics during gestation. Quality of clinical and preclinical studies was assessed by the Newcastle–Ottawa Scale and the SYRCLE’s risk of Bias tool, respectively. In total, 73 studies were selected for qualitative synthesis and three studies were selected for quantitative synthesis. Of preclinical studies, 93% found one or more adverse effects of prenatal exposure to antipsychotics or lithium on neurodevelopment or behaviour. Only three clinical cohort studies have investigated the consequences of lithium exposure, all of which reported normal development. In 66% of clinical studies regarding antipsychotic exposure, a transient delay in neurodevelopment was observed. The relative risk for neuromotor deficits after in utero exposure to antipsychotics was estimated to be 1.63 (95% CI 1.22–2.19; I2 = 0%). Preclinical studies suggest long-term adverse neurodevelopmental consequences of intrauterine exposure to either lithium or antipsychotics. However, there is a lack of high-quality clinical studies. Interpretation is difficult, since most studies have compared exposed children with their peers from the unaffected population, which did not allow correction for potential influences regarding genetic predisposition or parental psychiatric illness.Electronic supplementary materialThe online version of this article (10.1007/s00787-018-1177-1) contains supplementary material, which is available to authorized users.
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