Geneticists claim that major depression is at least half caused by genes, but this is not easily squared with the massive amount of evidence that social conditions and childhood experiences are far more significant.
A study, reported in Psychological Medicine, of 6,663 Canadians followed over a two-year period showed that if they suffered extreme stress (such as hostile bosses or repetitive tasks) at work they were nearly two-and-a-half times more likely to suffer a major depressive episode. This impact was regardless of other factors which also increased the risk, such as traumatic childhood and adulthood experiences, and lack of education.
Implication: while genes could've made these people more vulnerable to extreme stress, we cannot do anything about those; we can, however, create less Americanised work environments.
A review of the evidence regarding ageing and memory (reported in Psychological Bulletin) calls into question the idea that forgetfulness is an inevitable consequence of getting older. Apart from obvious factors, such as taking exercise and keeping mentally active (Scrabble, crosswords, etc), it shows that memory loss often relates to the change in one's social role after retirement, so that you are less likely to feel the pressure to remember so much and so often.
What's more, cultural stereotypes of the elderly can lead them to start seeing themselves as more forgetful, making them so in reality.
Implication: keep up with the Who Wants To Be A Millionaire? questions.