căng thẳng và những chàng trai với những phản ứng cortisol thấp hơn cũng cho thấy sử dụng cần sa nhiều hơn nữa. Moss et al. (1999) cho rằng hyporeactivity trong những chàng trai này có thể đại diện cho một sự thích nghi để tiếp xúc mãn tính ở mức cao của sự căng thẳng. | 682 Adolescent Substance Use stressor and that those boys with lower cortisol responses also showed more marijuana use. Moss et al. 1999 suggest that hyporeactivity in these boys may represent an adaptation to chronic exposure to high levels of stress. Finally Iacono et al. 1999 suggest that adolescents at risk for substance use problems show poor modulation of stress responses as reflected in an ability to control psychophysiological arousal in predictable versus unpredictable exposures to a laboratory stressor. Although the possibility that high-risk adolescents show abnormalities in stress response is potentially of great etiological importance very few empirical studies particularly of girls have examined this so conclusions must remain preliminary at this point. The Role of Emotional Distress The relation of emotional distress to adolescent substance use and substance use disorders has not been consistently upheld. Many studies have reported cross-sectional correlations between negative affect and adolescent substance use Chassin Pillow Curran Molina Barrera 1993 Cooper Frone Russell Mudar 1995 as well as substantial comorbidity between clinically diagnosed depression and adolescent nicotine dependence Fergusson Lynsky Horwood 1996b alcoholism Rohde Lewin-sohn Seeley 1996 and drug abuse or dependence Deykin Buka Zeena 1992 . However other researchers have argued that negative affectivity has only weak relations to adolescent substance use compared to factors such as peer affiliations and that effects of emotional distress are weak and indirect Swaim Oetting Beauvais 1989 . Moreover studies considering the role of negative affect have often failed to consider the effects of externalizing symptoms and conduct problems. Because there is considerable covariation between internalizing and externalizing symptoms it has not been clearly established that negative affect has a unique relation to adolescent substance use above and beyond co-occurring conduct problems .
