This study used longitudinal data from the UK National Child Development Study (N = 5844) to examine whether mental health measured at age 42 was associated with living in a stepfamily. Accounting for the potential selection of those with mental health problems at the onset of family formation (at age 23) into, or out of, stepfamilies we show that stepparents, their partners and particularly those in dual stepparent families all had worse mental health than parents in ‘first families’. It was also found that the mental health of men was worse if they were a stepparent than if they were the partner of a stepparent, while the reverse was the case for women
