Miriam Schneider

Bio: Miriam Schneider is an academic researcher from Heidelberg University. The author has contributed to research in topics: Cannabinoid & WIN 55,212-2. The author has an hindex of 30, co-authored 62 publications receiving 3317 citations. Previous affiliations of Miriam Schneider include University of Cologne & University of Bremen.

Puberty as a highly vulnerable developmental period for the consequences of cannabis exposure.

Abstract: During puberty, neuronal maturation of the brain, which began during perinatal development, is completed such that the behavioral potential of the adult organism can be fully achieved. These maturational events and processes of reorganization are needed for the occurrence of adult behavioral performance but simultaneously render the organism highly susceptible to perturbations, such as exposure to psychoactive drugs, during this critical developmental time span. Considering the variety of maturational processes occurring in the endocannabinoid system during this critical period, it is not surprising that the still-developing brain might by highly susceptible to cannabis exposure. Emerging evidence from human studies and animal research demonstrates that an early onset of cannabis consumption might have lasting consequences on cognition, might increase the risk for neuropsychiatric disorders, promote further illegal drug intake and increase the likelihood of cannabis dependence. These findings suggest that young people represent a highly vulnerable cannabis consumer group and that they run a higher risk than adult consumers of suffering from adverse consequences from cannabinoid exposure. The aim of the present review is to provide an overview over the possible deleterious residual cannabinoid effects during critical periods of postnatal maturation and to offer a more precise delineation of the vulnerable time window for cannabinoid exposure.

Adolescence as a vulnerable period to alter rodent behavior

Abstract: Adolescence and puberty are highly important periods for postnatal brain maturation. During adolescence, drastic changes of neuronal architecture and function occur that concomitantly lead to distinct behavioral alterations. Unsurprisingly in view of the multitude of ongoing neurodevelopmental processes in the adolescent brain, most adult neuropsychiatric disorders have their roots exactly during this time span. Adolescence and puberty are therefore crucial developmental periods in terms of understanding the causes and mechanisms of adult mental illness. Valid animal models for adolescent behavior and neurodevelopment might offer better insights into the underlying mechanisms and help to identify specific time windows with heightened susceptibility during development. In order to increase the translational value of such models, we urgently need to define the detailed timing of adolescence and puberty in laboratory rodents. The aim of the present review is to provide a more precise delineation of the time course of these developmental periods during postnatal life in rats and mice and to discuss the impact of adolescence and related neurodevelopmental processes on the heightened susceptibility for mental disorders.

The environment and schizophrenia

Abstract: Psychotic syndromes can be understood as disorders of adaptation to social context. Although heritability is often emphasized, onset is associated with environmental factors such as early life adversity, growing up in an urban environment, minority group position and cannabis use, suggesting that exposure may have an impact on the developing 'social' brain during sensitive periods. Therefore heritability, as an index of genetic influence, may be of limited explanatory power unless viewed in the context of interaction with social effects. Longitudinal research is needed to uncover gene-environment interplay that determines how expression of vulnerability in the general population may give rise to more severe psychopathology.

Persistent cannabis users show neuropsychological decline from childhood to midlife

Abstract: Recent reports show that fewer adolescents believe that regular cannabis use is harmful to health. Concomitantly, adolescents are initiating cannabis use at younger ages, and more adolescents are using cannabis on a daily basis. The purpose of the present study was to test the association between persistent cannabis use and neuropsychological decline and determine whether decline is concentrated among adolescent-onset cannabis users. Participants were members of the Dunedin Study, a prospective study of a birth cohort of 1,037 individuals followed from birth (1972/1973) to age 38 y. Cannabis use was ascertained in interviews at ages 18, 21, 26, 32, and 38 y. Neuropsychological testing was conducted at age 13 y, before initiation of cannabis use, and again at age 38 y, after a pattern of persistent cannabis use had developed. Persistent cannabis use was associated with neuropsychological decline broadly across domains of functioning, even after controlling for years of education. Informants also reported noticing more cognitive problems for persistent cannabis users. Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline. Further, cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users. Findings are suggestive of a neurotoxic effect of cannabis on the adolescent brain and highlight the importance of prevention and policy efforts targeting adolescents.