Table 1.

Summary of key articles and findings on the effects of cannabis across adolescents, emerging/young adults, and older adults.

Study	Developmental Period	Study Design	Key Findings
Rubino et al., 2015 16	Adolescents & Emerging Adults (M age = 17.8 – 24.3)	Meta-analysis of neuroimaging studies of cannabis users vs. non-users	Cannabis users have altered neural activity during neurocognitive tasks.
Scott et al., 2018 4	Emerging Adults (M age = 20.6 – 20.8)	Meta-analysis, primarily of regular cannabis users	Cannabis users performed worse on learning (d=−0.33), shifting (d=−0.30), processing speed (d=−0.26), delayed memory (d=−0.26), inhibitory (d=−0.25), working memory (d=−0.22), and attention (d=−0.21). Effects do not continue after 72 hours since last use.
Bloomfield et al., 2019 53	Adolescents & Young Adults	Review of acute and chronic effects	Chronic cannabis users may have anomalous glutamatergic and GABAergic functioning in neurocognitive substrates, which may increase risk for neuropsychiatric problems.
Crane et al., 2013 33	Emerging & Young Adults	Review of acute and non-acute effects in regular users	Cannabis acutely impairs episodic and working memory, attentional processing, and executive functioning (shifting) in adults. Non-acute impairments in episodic memory are seen in adults, but level of use likely plays a role.
Broyd et al., 2016 35	Primarily Young Adults	Review of acute effects and chronic effects	Acute and chronic effects of cannabis on poorer verbal learning, verbal memory, attention, psychomotor functioning. Tolerance may not reduce acute neurocognitive effects of cannabis.
Di Marzo et al., 2015 7	Adolescents through Older Adults (primarily from animal models)	Review of the endocannabinoid system in aging and neurodegenerative disorders	CB1 receptor density decreases by 50% from adolescence through older adulthood. Endocannabinoid changes may broadly increase risk for neurodegenerative diseases.

Note. Mean ages are listed for the meta-analyses that included this information.