The last chapter gave a hint that psychosocial factors might playa role in creating vulnerability to depression as well as provoking it. To summarize: while almost all the women in Camberwell who developed depression in the year of the survey had a severe event or major difficulty, only a fifth of those with such provoking agents broke down. What about the exceptions? Why in general are some far less vulnerable and, in particular, why are middle-class women so protected? Since one in three working-class women with a provoking agent and only one in twelve middle-class women were onset cases, any explanation of this class difference would go a long way to explain the general question of vulnerability (Table 6, chapter 10).