A systematic review of the effect of cannabidiol on cognitive function: Relevance to schizophrenia

Abstract

Background and objectives Cognitive impairment is a core symptom domain of schizophrenia, neurological disorders and substance abuse. It is characterised by deficits in learning, memory, attention and executive functioning and can severely impact daily living. Antipsychotic drugs prescribed to treat schizophrenia provide limited cognitive benefits and novel therapeutic targets are required. Cannabidiol (CBD), a component of the cannabis plant, has anti-inflammatory and antipsychotic-like properties; however, its ability to improve cognitive impairment has not been thoroughly explored. The aim of this systematic review was to evaluate preclinical and clinical literature on the effects of CBD in cognitive domains relevant to schizophrenia. Methods A systematic literature search was performed across numerous electronic databases for English language articles ( January 1990-March 2016, with 27 articles (18 preclinical and 9 clinical studies) included in the present review. Results CBD improves cognition in multiple preclinical models of cognitive impairment, including models of neuropsychiatric (schizophrenia), neurodegenerative (Alzheimer's disease), neuro-inflammatory (meningitis, sepsis and cerebral malaria) and neurological disorders (hepatic encephalopathy and brain ischemia). To date, there is one clinical investigation into the effects of CBD on cognition in schizophrenia patients, with negative results for the Stroop test. CBD attenuates Δ 9 -THCinduced cognitive deficits. Conclusions The efficacy of CBD to improve cognition in schizophrenia cannot be elucidated due to lack of clinical evidence; however, given the ability of CBD to restore cognition in multiple studies of impairment, further investigation into its efficacy in schizophrenia is warranted. Potential mechanisms underlying the efficacy of CBD to improve cognition are discussed.

Does Cannabis Composition Matter? Differential Effects of Delta-9-tetrahydrocannabinol and Cannabidiol on Human Cognition

“…So far, the only published study on the acute effect of CBD in schizophrenia has not shown any significant cognitive improvement [63]. Promising results of beneficial effects of CBD on cognition in the context of neuropsychiatric diseases come from preclinical studies on Alzheimer’s disease (AD), indicating improved recognition, social recognition, and spatial memory in AD paradigms following acute and chronic CBD treatment (reviewed in [80]). To our knowledge, no studies have explored the effect of CBD on cognition in other drug-induced states.…”

Pharmacological properties of cannabidiol in the treatment of psychiatric disorders: a critical overview

“…As a whole, these findings are not surprising, especially because preclinical studies attributed the potential role of CBD in the treatment of cognitive impairment to its capacity to reduce both inflammatory state and oxidative stress as well to promote neurogenesis by increasing brain-derived neurotrophic factor levels (Osborne et al 2017). Finally, the activity of CBD towards 5HT1A and adenosine A2A receptors may also contribute to improve cognitive performances (Osborne et al 2017).…”

“…Finally, the activity of CBD towards 5HT1A and adenosine A2A receptors may also contribute to improve cognitive performances (Osborne et al 2017).…”

“…drug, as well as a pro-cognitive (Osborne et al 2017) and antidepressant (de Mello Schier et al 2014) compound. Therefore, it is not surprising that CBD has been considered as a new potential treatment in several psychiatric disorders.…”

Wirksamkeit von Cannabidiol: Klinische Studien mit Cannabidiol und Cannabidiol-haltigen Extrakten

“…Eine noch nicht publizierte Studie mit 88 Patienten von GW Pharmaceuticals zeigt dagegen wiederum eine antipsychotische Wirkung [15]. In einem systematischen Review wurde festgestellt, dass die Evidenz für eine Wirkung auf die kognitive Funktion bei Schizophrenie-Patienten beschränkt ist [27]. …”