Totality of the Evidence Suggests Prenatal Cannabis Exposure Does Not Lead to Cognitive Impairments: A Systematic and Critical Review

Abstract

Background: Despite limited data demonstrating pronounced negative effects of prenatal cannabis exposure, popular opinion and public policies still reflect the belief that cannabis is fetotoxic. Methods:This article provides a critical review of results from longitudinal studies examining the impact of prenatal cannabis exposure on multiple domains of cognitive functioning in individuals aged 0 to 22 years. A literature search was conducted through PsycINFO, PubMed, and Google Scholar. Articles were included if they examined the cognitive performance of offspring exposed to cannabis in utero.Results: An examination of the total number of statistical comparisons (n = 1,001) between groups of participants that were exposed to cannabis prenatally and non-exposed controls revealed that those exposed performed differently on a minority of cognitive outcomes (worse on <3.5 percent and better in <1 percent). The clinical significance of these findings appears to be limited because cognitive performance scores of cannabis-exposed groups overwhelmingly fell within the normal range when compared against normative data adjusted for age and education. Conclusions:The current evidence does not suggest that prenatal cannabis exposure alone is associated with clinically significant cognitive functioning impairments.

Prenatal Cannabinoid Exposure: Emerging Evidence of Physiological and Neuropsychiatric Abnormalities

“…However, most performance effects from these cohorts were relatively subtle, and inconsistencies were present. Indeed, a recent systematic review of these data and other smaller cohorts determined that outcomes differed on only 4.3% of cognitive measures (with cannabis exposure being associated with worse outcomes in 3.4% of cognitive measures) ( 84 ). This review also concluded that the statistical differences were not clinically significant.…”

Commentary: Totality of the Evidence Suggests Prenatal Cannabis Exposure Does Not Lead to Cognitive Impairments: A Systematic and Critical Review

“…11:816. doi: 10.3389/fpsyg.2020.00816 Recent legalization of cannabis use in 40 American states and all Canadian provinces and territories has created an urgent need for evidence surrounding the implications of in-utero cannabis exposure for infant and child health outcomes, including cognitive functioning. A recently published systematic review by Torres et al (2020) aimed to synthesize and critically appraise results from longitudinal studies examining the impact of prenatal cannabis exposure on multiple domains of cognitive functioning in individuals aged 0 to 22 years. The authors present a strong critical appraisal of the included literature and clearly highlight the limited evidence in this area.…”

Response: Commentary: Totality of the Evidence Suggests Prenatal Cannabis Exposure Does Not Lead to Cognitive Impairments: A Systematic and Critical Review

“…11:1891. doi: 10.3389/fpsyg.2020 We appreciate the expressed interest of Chaput et al (2020) in our recent critical review of the literature investigating the impact of prenatal cannabis exposure on subsequent cognitive functioning of offspring (Torres et al, 2020). We concluded that the available empirical "evidence does not suggest that prenatal cannabis exposure alone is associated with clinically significant cognitive functioning impairments."…”