Second, individuals in all four trajectories of elevated internalizing symptoms were more likely to have a mother with a history of depression than were individuals in the SL class. A relationship between maternal depression and the emotional symptoms scale of the SDQ has been previously reported for this sample (Araya et al., 2009). Reporting bias in these mothers might have resulted in their description of elevated levels of internalizing in their child, though empirical studies of such an effect have produced mixed results (Fergusson et al., 1993; Sawyer et al., 1998). It is also possible that children of mothers with a history of depression actually experience more internalizing problems than their peers. With the current data is it not possible to determine whether either scenario is at work here. In addition, as noted in the Methods, some modest differences exist between the original sample and the sample retained in these analyses. These differences could have lead to slight biases in the results.
