FIGURE 1.9 Differential Sensitivity The risk score for these boys was a simple 0 to 3, with 1 point for each of the following: drank alcohol, smoked marijuana, had sex. As shown, most had done none of these at age 11, and, by age 14, most had done one (usually drunk beer). However, some of those at genetic risk had done all three, and many had done two. For them, and only them, the seven-session intervention made a difference.