I think lack of meaningful relationships, especially long-term marriage. Divorced, single, seperated men and women alway start experiencing mental issues after above 35. Those with no kids, and spouses are even at worse state, they go completely nuts. Traditional family where man and woman and thriving kids live in one roof has shown to be the cure of mental illness (Avasthi, 2010). In"Preserve and strengthen family to promote mental health", Avashthi detailed good data that should be modelled!. Men and women should start relationship in 20s and stay married through 90s, and mental health will be cut by more than half. That large study in India showed traditional marriage is the key to weakening mental illness!
With children, Results from growth curve models confirm that, even before marital breakup, children whose parents later divorce exhibit higher levels of anxiety/depression and antisocial behavior than children whose parents remain married. There is a further increase in child anxiety/depression but not antisocial behavior associated with the event of parental divorce itself. Controlling for predivorce parental socioeconomic and psychosocial resources fully accounts for poorer child mental health at initial interview among children whose parents later divorce, but does not explain the divorce-specific increase in anxiety/depression. Finally, a significant interaction between parental divorce and predivorce levels of family dysfunction suggests that child antisocial behavior decreases when marriages in highly dysfunctional families are dissolved (Strohschein, 2005).