The effects of smoked Marijuana on interpersonal distances in small groups

Twelve adult male research volunteers lived, in groups of three, in a residential laboratory for 7 days. During the later portion of the day (1700-2345), they had the option to socialize with or without access to video-taped films. Four cigarettes containing active marijuana (0-2.7% delta 9 THC) were smoked daily, two prior to and two during the social access period. Active marijuana decreased verbal and either increased or decreased non-verbal interaction time depending on baseline rates. Decreased verbal interactions were associated with increased interpersonal distance.