BackgroundMultiple relapses characterise the course of illness in most patients with schizophrenia, yet the nature of these episodes has not been extensively researched and clinicians may not always be aware of important implications.MethodsWe critically review selected literature regarding the nature and underlying neurobiology of relapse.ResultsRelapse rates are very high when treatment is discontinued, even after a single psychotic episode; a longer treatment period prior to discontinuation does not reduce the risk of relapse; many patients relapse soon after treatment reduction and discontinuation; transition from remission to relapse may be abrupt and with few or no early warning signs; once illness recurrence occurs symptoms rapidly return to levels similar to the initial psychotic episode; while most patients respond promptly to re-introduction of antipsychotic treatment after relapse, the response time is variable and notably, treatment failure appears to emerge in about 1 in 6 patients. These observations are consistent with contemporary thinking on the dopamine hypothesis, including the aberrant salience hypothesis.ConclusionsGiven the difficulties in identifying those at risk of relapse, the ineffectiveness of rescue medications in preventing full-blown psychotic recurrence and the potentially serious consequences, adherence and other factors predisposing to relapse should be a major focus of attention in managing schizophrenia. The place of antipsychotic treatment discontinuation in clinical practice and in placebo-controlled clinical trials needs to be carefully reconsidered.

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Rodent marble-burying behavior in the marble-burying test (MBT) is employed as a model or measure to study anxiety-and compulsive-like behaviors or anxiolytic and anticompulsive drug action. However, the test responds variably to a range of pharmacological interventions, and little consensus exists regarding specific methodologies for its execution. Regardless, the test is widely applied to investigate the effects of pharmacological, genetic, and behavioral manipulations on purported behaviors related to the said neuropsychiatric constructs. Therefore, in the present review we attempt to expound the collective translational significance of the MBT. We do this by (1) reviewing burying behavior as a natural behavioral phenotype, (2) highlighting key aspects of anxiety and obsessive-compulsive disorder from a translational perspective, (3) reviewing the history and proof of concept of the MBT, (4) critically appraising potential methodological confounds in execution of the MBT, and (5) dissecting responses of the MBT to various pharmacological interventions. We conclude by underlining that the collective translational value of the MBT will be strengthened by contextually valid experimental designs and objective reporting of data.

Stress-restress-mediated glucocorticoid release activates iNOS, followed by a reactive downregulation of hippocampal NMDA receptors and dysregulation of inhibitory GABA pathways. The role of NO in neuronal toxicity, and its regulation by glutamate and GABA has important implications in stress-related hippocampal degeneration.

Outside of the dopaminergic model, the potential pathogenesis of schizophrenia has yet to be fully elucidated, but common themes include neuropil shrinkage, the development of abnormal neuronal circuitry, and a chronic inflammatory state which further disrupts neuronal function. Whilst some early non-dopaminergic treatments show promise, none have yet to be fully studied in appropriately structured randomized controlled trials and they remain little more than potential attractive targets.