Introduction
Human sleep is fundamental for the proper occurrence of organic functions. Hence, the lack of sleep can impair cognitive function, resulting in emotional problems, memory changes and disease onset. However, it is worth noting that sleep is influenced by outside factors, such as drug use. In this sense, the aim of this work is to analyze studies that had as their research object the influence of recreational marijuana on the sleep quality of adults.

Methods
A high-sensitivity research was conducted in databases (Biblioteca Virtual em Saúde, Medline via Pubmed, Cochrane, Embase, Web of Science and Scopus) using descriptors linked to marijuana and sleep habits.

Results
Eighteen studies from four countries were included with a total sample size of 29,858 participants. It was identified that marijuana affects sleep characteristics–such as latency and duration–with these changes being more evident in users who make greater use of marijuana and in those who started premature use.

Conclusions
It was observed that most articles demonstrated a detrimental effect of recreational cannabis use on the quality of sleep in adults.