A major symptom of schizophrenia is cognitive impairment with very limited treatment options. The present antipsychotic drugs have limited effectiveness in treating these symptoms and can lead to serious side-effects. This has led to a requirement for novel therapeutics. The non-intoxicating phytocannabinoid, Cannabidiol (CBD) has displayed pro-cognitive effects in several conditions of ailments, including a Poly I:C induced maternal immune activation model of schizophrenia, but the mechanisms that form the basics of the efficacy of CBD need investigation. Muscarinic neurotransmission is involved to a great extent in the cognitive impairments of schizophrenia though the impact of CBD upon this system is unknown.
This study investigated changes in markers of muscarinic neurotransmission within the prefrontal cortex (PFC) and hippocampus (HPC) following CBD treatment. Poly I:C is an immunostimulant and consist of a synthetic, double-stranded RNA, and is a normal tool for scientific study on the immune system. In this experiment female rats were administered poly I:C or saline. Adult offspring were treated for three weeks with CBD (10 mg/kg). Changes in muscarinic M1/M4 receptor (M1/M4R) binding density was examined along with levels of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) protein expression.
The key highlights found were:
- Male poly I:C offspring have reduced M1/M4R density and ChAT in the PFC and hippocampus
- CBD was able to treat deficits in cholinergic markers in the brain of male poly I:C offspring
- ChAt levels correlated positively to working memory performance in the T Maze. The T maze is generally used to assess spatial working memory in rats and mice.
- Cholinergic markers remain unchanged in female offspring and it showed no changes in muscarinic signalling
- This study disclosed a role for cholinergic signalling in pro-cognitive effects of CBD. The findings indicate that CBD can normalise muscarinic neurotransmission imbalances in male poly I:C offspring in regions of the brain implicated in cognition.
CBD Can Unlock New Cognitive Therapy For Schizophrenia And Improve Cognitive Ability
Cannabinoids can impact the neurochemical processes within the PFC that are linked with cognitive impairments. In rodents, it has been found that acute administration of cannabinoid agonists results in deficits in working memory, reversal learning and attentional function. Preclinical studies have also revealed that the endogenous cannabinoid system can restoratively regulate some mnemonic processes. Cannabinoids like CBD can extend direct neurological support for several ailments that affect the brain from schizophrenia to dementia.
CBD’s capacity for easing signs of cognitive deficits in schizophrenia in various researches on rat models have proved that ‘chronic’ administration of CBD appeared to attenuate the cognitive deficits and social withdrawal that afflicts individuals suffering from schizophrenia which the research team simulated in rats utilizing prenatal poly I:C infection.
Such research showed that CBD restored recognition and working memory as well as social behaviour to proper levels. Such findings are regarded as interesting as they indicate that CBD can treat some of the signs of schizophrenia that are probably resistant to present medications. Further, CBD therapy did not change body weight or intake of food which are general side effects found in antipsychotic drug therapy.
This review made us aware that CBD not only improves memory, cognition and memory in robust brains, but can also improve aspects of learning, memory and cognition in ailments linked with cognitive impairment like schizophrenia and Alzheimer’s disease and other neurological and neuro-inflammatory ailments. These new findings display promising consequences for likely use of CBD in treating the social withdrawal and cognitive deficits of schizophrenia.