# A neurobiological investigation of cannabis use and misuse in Veterans

> **NIH VA IK2** · VA CONNECTICUT HEALTHCARE SYSTEM · 2023 · —

## Abstract

In individuals with psychosis cannabis is associated with worse prognosis, exacerbation of psychotic
symptoms, impaired cognition, functional disability, violence, increased frequency and duration of
hospitalizations, and elevated healthcare costs. Despite this, there are high rates of co-occurring cannabis use
in psychosis, and rising cannabis use amongst Veterans. With legalization, commercialization, and increasing
potency of cannabis and decreasing risk perception, there is cause for alarm especially for those with psychosis.
Critically, there are no proven or approved treatments for cannabis use disorder in individuals with psychosis.
While antipsychotic medications are useful for decreasing psychotic symptoms, they have little effect on
decreasing cannabis use. Although nascent research suggests that repetitive transcranial magnetic stimulation
(rTMS) and psychosocial interventions (i.e., motivational enhancement therapy) may reduce cannabis use and/or
psychosis, responses have been mixed. One possible reason that treatments may fail is that they may rely on
intact synchronized neural activity necessary for information processing, learning and memory.
 Converging evidence suggest deficits in neural synchrony in regions involved in learning and memory are
implicated in the pathophysiology of psychosis and psychoactive effects of cannabis. In those with psychosis,
deficits in coordinated neural activity in theta (4-7Hz) and gamma (30-80Hz) ranges, which are centrally involved
in learning and cognition and particularly working memory (WM), have been observed. In vitro and in vivo studies
and our experimental work in healthy controls have shown cannabinoid receptor type 1 agonists decrease theta
and gamma synchrony and increase noise (random activity), as well as alter functional connectivity in the working
memory network (WMN). While a scant literature, experimental studies in psychosis have shown cannabinoids
increase cognitive dysfunction and reduced hippocampal-striatal functional connectivity during a learning task.
Despite these initial findings, further work is needed on the impact of cannabinoids on neural synchrony in those
with psychosis, as identifying implicated neural mechanisms may lead to development of new interventions.
 Powerful tools previously used to investigate neural synchrony and functional connectivity (coordinated
activity), such as electroencephalography (EEG) and functional magnetic resonance imaging, can be
complemented with magnetoencephalography (MEG). MEG is a non-invasive, functional measure of magnetic
fields produced by neural activity with excellent temporal and spatial resolution. MEG has been critical for
understanding neural synchrony and working memory in other disorders, like Alzheimer’s Disease. While MEG
is sensitive to tangential currents, EEG is sensitive to tangential and radial currents. Together, MEG and EEG
provide complementary information for more accurate determination of neural mechanisms. De...

## Key facts

- **NIH application ID:** 10588526
- **Project number:** 1IK2CX002547-01A1
- **Recipient organization:** VA CONNECTICUT HEALTHCARE SYSTEM
- **Principal Investigator:** Ashley Schnakenberg Martin
- **Activity code:** IK2 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2023
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2023-01-01 → 2027-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10588526

## Citation

> US National Institutes of Health, RePORTER application 10588526, A neurobiological investigation of cannabis use and misuse in Veterans (1IK2CX002547-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10588526. Licensed CC0.

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