Depression is one of the most commonly occuring mental illnesses, with a lifetime prevalence of 9.4%

(Kessler, 2012). The World Health Organization has ranked depression among the top 4 leading causes of

disability worldwide (WHO, 2008). Rates of depression also appear to be universally higher for women

than men, with women being roughly at 2 times greater risk of developing depression than males

(Kessler, 2003; Weissman & Klerman, 1977). This sex difference has been attributed to differences in

seeking out rewarding behaviours (Ryba & Hopko, 2012), response toward emotionally salient stimuli

(Bradley, Codispoti, Sabatinelli, & Lang, 2001) and differences in underlying neurocircuitry including the

inferior frontal gyrus and left amygdala (Stevens & Hamann, 2012). Children of parents diagnosed with

major depressive disorder (MDD) are also 2-3 times more likely to develop depression (Johnstone,

Lawrie, & Cosway, 2002; Lieb, Isensee, Hofler, & Wittchen, 2002; Weissman et al., 2006) and 2-3 times

more likely to develop other anxiety or behavioural disorders (Lieb et al., 2002; Mars et al., 2012;

Weissman et al., 2006). This risk suggests the influence of either familial genetic loading or

environmental factors. The most commonly reported risk allele is a low-expressing variant of the

serotonin transporter gene (5HTTLPR) (for more information please see appendix 1b).

Maternal behaviours towards their own children can also be affected by depression. Mothers become less

emotionally responsive to their infants as a result of depression and this has noticable effects on the longterm

behavioural and social outcome of the offspring. In infancy, these children are more likely to show

avoidance or disorganized attachment behaviours (to strange situation tasks) (Madigan, Moran, &

Schuengel, 2007; Martins & Gaffan, 2000) and higher rates of internalizing/ externalizing behavioural

problems (Garai et al., 2009) than children of non-depressed mothers. Children of depressed mothers have

poorer scores on the Child Behavioural Checklist (CBCL) when children were exposed to maternal

depression during their first year of life (Bagner, Pettit, Lewinsohn, & Seeley, 2010). They also show

lower scores on the Peabody picture vocabulary test; a measure of verbal fluency (Brennan et al., 2000),

lower scores on the Rey Auditory Verbal Learning task; a measure of declarative recall memory (Mannie,

Barnes, Bristow, Harmer, & Cowen, 2009), but, executive functioning does not seem to be affected by

parental depression (Micco et al., 2009). However, emotional labeling deficits remain the most commonly

reported deficit among offspring of depressed parents, suggesting difficulties in the emotional processing

network is part of the core psychopathology among at-risk children.

The purpose of this study is to determine the extent to which childhood emotional face labeling ability

mediates risk for depression (by having one or more parent with depression) and the psychiatric outcome

in adolescence. We predict that errors in emotional labeling (measured at 8 years of age) in childhood will

be significantly associated with (1) exposure to maternal depression in childhood, and (2) depression or

other psychiatric effects in adolescence. We predict this emotional face labeling ability will account for

part of the measured association between maternal depression severity and youth depression in

adolescence. Furthermore, we predict that the child's genetic risk for depression (identified by the lowexpressing

serotonin allele status) will be a moderator between maternal depression exposure and their

emotional face labeling ability. We predict that short allele status in the children will increase the effect of

exposure to maternal depression and this effect with be seen as greater difficulty on the