Adult cortical plasticity depends on an early postnatal critical period

Development of the cerebral cortex is influenced by sensory experience during distinct phases of postnatal development known as critical periods. Disruption of experience during a critical period produces neurons that lack specificity for particular stimulus features, such as location in the somatosensory system. Synaptic plasticity is the agent by which sensory experience affects cortical development. Here, we describe, in mice, a developmental critical period that affects plasticity itself. Transient neonatal disruption of signaling via the C-terminal domain of "disrupted in schizophrenia 1" (DISC1)-a molecule implicated in psychiatric disorders-resulted in a lack of long-term potentiation (LTP) (persistent strengthening of synapses) and experience-dependent potentiation in adulthood. Long-term depression (LTD) (selective weakening of specific sets of synapses) and reversal of LTD were present, although impaired, in adolescence and absent in adulthood. These changes may form the basis for the cognitive deficits associated with mutations in DISC1 and the delayed onset of a range of psychiatric symptoms in late adolescence.

The development of Cannabidiol as a psychiatric therapeutic:a review of its antipsychotic efficacy and possible underlying pharmacodynamic mechanisms

Cannabidiol (CBD), a once-considered inert cannabis constituent, is one of two primary constituents of cannabis, alongside delta-9-tetrahydrocannabinol (?9-THC/THC). In the last 30 years, CBD has become implicated with a range of pharmaceutical mechanisms of great therapeutic interest and utility. This review details the literature speculating CBD’s attenuation of psychotic symptoms, particularly in light of a marked elevation in mean THC concentrations, and a concomitant decline in CBD concentrations in the prevalent U.K street market cannabis derivatives since c. 2000. CBD is purported to exhibit pharmacology akin to established atypical antipsychotics, whilst THC has been implicated with the precipitation of psychosis, and the induction of associated symptoms. The aim of the review was to clarify the conjecture surrounding CBD’s antipsychotic efficacy, before going on to detail prominent theories about its associated pharmacodynamics. Were CBD’s antipsychotic efficacy established, then there is potential for major latent anthropological repercussions to manifest, such as significant elevations in psychosis manifestations in the U.K. The review found a largely affirmative body of evidence asserting CBD’s antipsychotic efficacy. CBD exhibited capacity to attenuate natural and artificially induced psychoses in both animal and human cohorts, the latter of which included individuals considered resistant to conventional treatment. CBD also shows promising potential for use as an antipsychotic drug for Parkinson’s disease (PD) patients with psychosis, owing to its low rate of extra-pyramidal side-effect induction. A range of potential pharmacological mechanisms behind CBD’s neuroleptic pharmacology are outlined, with particular emphasis on its prevention of the hydrolysis and reuptake of the endogenous cannabinoid, anandamide. However, given the nebular aetiological basis for psychoses, explicit conclusions on how CBD attenuates psychotic symptoms remains to be determined.

Psychotic symptoms are associated with physical health problems independently of a mental disorder diagnosis:results from the WHO World Health Survey

This study explored whether physical health problems are related to psychotic symptoms independently of a mental disorder diagnosis. A total of 224,254 subjects recruited for the World Health Organization World Health Survey were subdivided into those with both a lifetime diagnosis of psychosis and at least one psychotic symptom in the 12 months prior to the evaluation, those with at least one psychotic symptom in the past 12 months but no lifetime diagnosis of psychosis, and those without psychotic symptoms in the past 12 months and without a lifetime diagnosis of psychosis. The three groups were compared for the presence of medical conditions, health problems, and access to health care. Medical conditions and health problems (angina, asthma, arthritis, tuberculosis, vision or hearing problems, mouth/teeth problems, alcohol consumption, smoking, and accidents), medication consumption, and hospital admissions (but not regular health care visits) were more frequent in individuals with psychotic symptoms but no psychosis diagnosis, compared to those with no symptoms and no diagnosis. The number of medical conditions increased with the number of psychotic symptoms. Given the sample analyzed, this trend seems to be independent from the socio-economic development of the country or the specific health care system.