The authors explain that sensation seeking among early and middle adolescents is highly associated with drug use. This is alarming due to the data that show that early initiation of drug use is associated with an increased lifetime risk of drug use morbidity. Those who use drugs young often end up using drugs frequently and persistently. Although the rise in drug use among adolescents is clear, little is known about why it increases at this age. As such, this study was designed to better understand the relationship between drug use, sensation seeking, and pubertal development. The authors recruited 208 early and mid-adolescents between the ages of 11 and 14 years from a psychiatric clinic and 2 general pediatric clinics. Sensation seeking behavior was measured by administering the Sensation Seeking Scale for Children while pubertal development was measured through the use of a modified Pubertal Development Scale. Self-report questionnaire data were obtained about the use of nicotine, alcohol, and marijuana. The findings indicate that sensation seeking behavior was higher in males and females who reported nicotine and alcohol use and in males who reported only using marijuana. Sensation seeking behavior was also positively related to pubertal development in both males and females. Sensation seeking behavior was a mediating factor for both males and females in the relationship between pubertal development and drug use. The results show that puberty is associated with drug use and that vigilance must be exercised to interrupt the pattern of continued drug use into adulthood. Tables and references