Table 4.

Results of Multivariate Ordinary Least Squares Regression: Interactions of Season of Birth and Maternal Factors as Related to ADHD Symptoms in the Early Forties (N=548).

Independent Variables	ADHD Symptoms Beta (t-statistic)
Maternal Cigarette Smoking with Season of Birth
Maternal Cigarette Smoking × Winter	0.05 (0.86)
Maternal Cigarette Smoking × Spring	0.17 (2.64)**
Maternal Cigarette Smoking × Autumn	0.07 (1.22)
Maternal Depression with Season of Birth
Maternal Depression × Winter	−0.05 (−0.35)
Maternal Depression × Spring	0.12 (0.65)
Maternal Depression × Autumn	0.09 (0.54)
Maternal Low Self-Control with Season of Birth
Maternal Low Self-control × Winter	−0.003 (−0.01)
Maternal Low Self-control × Spring	−0.20 (−0.70)
Maternal Low Self-control × Autumn	0.26 (1.00)
Maternal Rebellion with Season of Birth
Maternal Rebellion × Winter	0.30 (1.58)
Maternal Rebellion × Spring	0.23 (1.00)
Maternal Rebellion × Autumn	0.20 (0.89)

Note:

^**p<0.01;

Seven main effects (three SOB indicator variables and four maternal factors), twelve interactive terms, and five control variables (gender, T8 age, T2 parental educational level, T2 household income, and county of origin) were included in the regression equation;

Born in the summer (June – August) was treated as a reference.