In contrast to numerous previous reports of sex differences in internalising/externalising behaviours, boys and girls did not significantly differ in terms of their SDQ total scores or emotional, peer, hyperkinetic or conduct problems except for a nonsignificant trend for more externalizing behaviours in boys ( t = 1.81, df = 92, p -value = 0.07).
We found nominally significant differences in two variables: During pregnancy, the feasibility study mothers had lived in more overcrowded conditions (mean crowding index, 1.75; 95% CI, 1.58–1.92) compared to the larger SPS cohort [(mean crowding index, 1.57; 95% CI, 1.55–1.59) (effect size, 0.20)] and had scored higher on the Edinburgh Depression Scale [(mean, 14.10; CI, 13.00–15.21) versus (mean, 12.88; CI, 12.74–13.03) effect size 0.21] (NB: a score of 13 or above indicates a high likelihood of depression).