Mental health in South Africa has been neglected as a public health and policy issue, particularly among adolescents. This is unfortunate, as nineteen percent of African adolescents in South Africa suffered from depression in 2014, and these rates were even higher for adolescents with mothers with poor mental health. Previous work has estimated the impact of parental depression on child depression in South Africa, and found it to be substantial, particularly for adolescent children. A teenager whose mother suffers from depression will have a risk of depression which is thirty percentage points higher than teens whose mothers do not suffer from depression. In order to decide on the best method of treatment to prevent transmission from occurring, it is necessary to disentangle the effect into its environmental and genetic components. There is no similar literature on this relationship in the South African context. This paper investigates the nature of depression transmission to African adolescents in South Africa, and finds that it is primarily environmental factors which account for the transmission of depression to children. Using a variety of techniques, we find that once the “nurture” effect has been accounted for, the “nature” effect is negligible. This implies that mitigating negative factors in a household, and in communities, as opposed to directly treating adolescent mental health using conventional approaches, may be the best approach, particularly in a country struggling with a lack of mental health professionals.