Ecology of adolescents' marijuana abuse

Sixteen adolescent marijuana abusers reported data on the ecology of their use over a 3-month period. Abusers recorded data on the day, date, time, place, frequency, and amount of use. They also included information on their mood and functioning, and with whom they used marijuana. Peak use occurred just prior to school, at lunch, and in the early evening. Adolescents' homes, friends' houses, school, and cars represented 67% of locations in which marijuana was used. Happy, relaxed, and tired comprised 81% of moods experienced during time of use. Average core network was 5.8 individuals while casual networks averaged 15.5 adolescents. Presence of others during use was associated with abusers' increased use and decreased functioning.