Department of Psychiatry, University of Wisconsin-Madison, Madison, Wisconsin
Department of Mental Hygiene, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland
Department of Psychiatry, University of Wisconsin-Madison, Madison, Wisconsin, USA
Correspondence: Dr Marilyn J. Essex, Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Boulevard, Madison, Wisconsin 53719, USA
Declaration of interest Funding was provided by the National Institute of Mental Health (RO1-MH44340), the John D. and Catherine T. MacArthur Foundation and the Wisconsin Center for Affective Science (P50-MH53524).
See editorial, pp.
9394, this issue.
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ABSTRACT |
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Aims To address these issues, while also taking account of child gender and family socio-economic status.
Method In a prospective community-based study, 421 kindergarten teachers rated children's symptoms. Previous assessments of maternal major depression indicated whether children were first exposed during infancy, in the toddler/pre-school period, or never.
Results Exposure during infancy was associated with high internalising symptoms, especially when co-occurring with high externalising symptoms. Initial exposure in the toddler/pre-school years increased the risk of pure externalising symptoms among girls.
Conclusions The association of child mental health symptoms with the timing of initial exposure to maternal depression highlights the need for effective prevention and intervention strategies addressed to the developmental issues of each period.
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INTRODUCTION |
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Background
It is well established that offspring of depressed mothers suffer a variety
of adverse outcomes (reviewed by Cummings
& Davies, 1994; Gotlib
& Goodman, 1999). Infants of depressed mothers have been found
to be more withdrawn, to have more difficult temperaments, and to be less
securely attached to their mothers (Field,
1992; Murray et al,
1996; Campbell & Cohn,
1997). Toddlers and pre-school children of depressed mothers have
been found to have more difficulties with self-regulation and in relationships
with peers and adults (Lyons-Ruth,
1992; Cicchetti et al,
1998). School-age children of depressed mothers have been found to
have even more difficulties (Anderson &
Hammen, 1993; Fergusson et
al, 1995).
With few exceptions (for example, Sinclair & Murray, 1998), prior studies have not employed a developmental perspective or prospective longitudinal designs of sufficient duration to investigate the association of earlier maternal depression with children's problems at later points, and none has specifically looked at the timing of depression. Timing is critical because it may interfere with mastery of developmental tasks such as attachment and emotion regulation during infancy, or self-regulation and social competence in the toddler/pre-school years (reviewed by Goodman & Gotlib, 1999). Also, to our knowledge, studies have not distinguished between child outcomes with co-occurring internalising and externalising symptoms, and those with pure forms of these symptoms.
Aims
The study addressed these issues by investigating the association of the
timing of maternal depression with child symptoms during the spring of the
children's kindergarten year, an important developmental point when
vulnerabilities established earlier may become risk factors as children
negotiate new relationships and the increased structure of school
(Entwisle & Alexander,
1989). We also distinguished between pure
internalising, pure externalising, and co-occurring symptoms. We
addressed three questions. First, are the risks of internalising and
externalising symptoms associated with differences in the timing of children's
initial exposure to maternal depression? Second, is the effect of the timing
different if pure forms of symptoms are distinguished from
co-occurring forms? And third, do symptom patterns vary according to child
gender or family socio-economic status as indexed by maternal education?
Hypotheses
Two major hypotheses were tested:
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METHOD |
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Demographic characteristics
The sample of 421 mothers used in the study was composed of 6% ethnic
minorities, 96% married, and 40% first-time mothers. The age range was 20-43
years, median 30 years. Two per cent had less than a high-school degree, 42%
were high-school graduates, 35% were college graduates and 21% had some
education beyond college. Annual family income ranged from $7500 to $200 000,
median $47 000. There were no significant differences between the 421 families
who are included in these analyses and the 139 who comprised the remainder of
the original eligible sample in terms of ethnicity, family income, maternal
education or parity, but the participating mothers were more frequently
married (96% v. 91%) and older (30 years v. 28 years).
Measures
Maternal major depression
The depression section of the National Institute of Mental Health
Diagnostic Interview Schedule (DIS)
(Robins et al, 1981)
was administered in home interviews to diagnose maternal major depression
during the first year post-partum and when the children were aged 3
and 4
years. Responses were scored for the presence of major
depression according to the DSMIIIR requirement of symptoms
corresponding to five or more criteria, including either depressed feelings or
loss of interest (American Psychiatric
Association, 1987). Two indices of the timing of children's
initial exposure were then derived:
For each index, 1 denotes initial exposure to maternal depression during that period and 0 denotes that the child was not first exposed during that period. Children who were never exposed to maternal major depression had scores of 0 on both indices.
Teacher ratings of child internalising and externalising
symptoms
Teachers completed the Health and Behaviour Questionnaire (HBQ) in the
spring of the kindergarten year. The HBQ is a multi-dimensional and
multi-informant instrument for middle childhood assessment (described fully by
Essex et al, 2001).
The mental health symptom items used in the study were derived from the
Ontario Child Health Study scales revised (OCHSR),
well-established measures with known reliability and validity
(Boyle et al, 1993).
The teacher form included a 14-item internalising scale (sub-scales of
depression and overanxious disorder) and a 24-item externalising scale
(sub-scales of oppositional defiant and conduct problems, and overt
aggression). Internal consistencies for all scales and sub-scales exceeded
0.70 and testretest reliabilities ranged from 0.71 to 0.94. A cut-off
point of the upper 25% of the distributions on the internalising and
externalising scales was used to define the children evidencing
high symptoms. This cut-off point was selected to ensure that
the children's scores fell within 1 standard deviation of the mean for clinic
samples in the multi-site casecontrol study that established the
effectiveness of the HBQ in discriminating between clinic-referred and
community groups of young children (Ablow
et al, 1999). Effect sizes of 1.0 (internalising) and 1.3
(externalising) were found for discriminations between community and
clinic-referred children. In addition, in a selected sample of children from
the present study, teacher HBQ ratings of externalising symptoms discriminated
between children who were high and low on a
parent-rated composite score for temperamental anger, activity, low control
and poor attention (effect sizes from 1.3 to 2.1). Teacher internalising
ratings on the HBQ, however, did not identify children who were
temperamentally fearful or sad.
Child gender and maternal educational level
Measures of child gender (boys, 0; girls, 1) and maternal education (high
school or less, 0; more than high school, 1) were also included, based on
prior findings demonstrating gender differences and the association of
maternal education with child problems
(Lyons-Ruth, 1992;
Sinclair & Murray, 1998).
The addition of income and paternal education, as components of socio-economic
status, did not improve any models described below.
Data analysis
In addition to descriptive statistics and chisquared analyses, two sets of
logistic regression analyses addressed the main questions. Predictors were the
indices of the timing of children's initial exposure to maternal depression
(never exposed was always the contrast group), child gender and
maternal education. Interactions of the timing indices and the other two
predictors were tested in separate models because of problems of
multi-colinearity. One-tailed tests were used for tests of stated hypotheses;
two-tailed tests of all other predictions. To reduce the risk of type II
error, only interactions significant at a 0.01 level or less are reported.
Following an analytic strategy used in other studies that have not differentiated children with pure symptoms from those with co-occurring symptoms, the first set of logistic regression analyses estimated separate models for internalising and externalising symptoms. These were followed by multinomial logistic regressions that included the distinction between the pure and co-occurring symptom groups. The model simultaneously estimated three equations to evaluate the influence of the predictors on the children's membership in the groups high internalising symptoms only v. low symptoms, high externalising symptoms only v. low symptoms, and high co-occurring symptoms v. low symptoms.
Because we used a clinically validated cut-off point of 25% to define high symptom groups, we also checked to see whether these results were robust. We were particularly sensitive to the common problem with this categorical approach that children whose symptoms were just above or below the threshold would not be distinguished from those at the more extreme ends of the distributions. When analyses were conducted using the upper 20% and the upper 30% of the distributions, no differences in results were obtained. Similarly, when analyses were conducted omitting the children in the third quartile, no differences in results were obtained. We therefore report only the results of the analyses using the 25% cut-off points.
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RESULTS |
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Effects of child gender and maternal education on child symptoms
Both child gender and maternal education were associated with children's
symptoms. When the pure and co-occurring symptom groups were
not distinguished, boys were significantly more likely than girls to
be in the high externalising group, 2 (1,
n=421)=5.89, P=0.015. However, when the group with
pure externalising symptoms was analysed separately from the
group with co-occurring symptoms, this gender effect was seen in the
pure externalising group,
2 (1,
n=421)=12.79, P<0.001, but not in the both
group,
2 (1, n=421)=0.52, P=0.470. There
were no significant gender differences for internalising symptoms.
Maternal education was also related to child symptoms. Children whose
mothers had a high-school education or less were significantly more likely to
be rated by teachers as high in co-occurring symptoms, 2 (1,
n=421)=16.68, P=0.001. There were no significant
associations between maternal education and teacher reports of
pure internalising or externalising symptoms
(Table 1).
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Timing of initial exposure to maternal depression and child
symptoms
Exposure in the infancy period (0-12 months)
Results from the first set of logistic analyses showed that when children
with pure forms of symptoms were combined with those with
co-occurring symptoms, exposure to maternal depression during infancy was
associated with greater odds of being in the high internalising (odds ratio
(OR) 3.01, 95% CI 1.55-5.83, P=0.001) and the high externalising
symptom groups (OR 2.15, 95% CI 1.07-4.32, P=0.016)
(Table 2). However, when
children with high co-occurring symptoms were distinguished from those with
pure symptoms, the multinomial logistic regressions showed
differences in risk. While children exposed to maternal depression during
infancy were more than twice as likely to be rated by kindergarten teachers as
high in pure symptoms (OR 2.23, 95% CI 0.94-5.37,
P=0.035), these odds were more than doubled for high levels of
co-occurring symptoms (OR 5.00, 95% CI 2.05-12.30, P<0.001). Of
particular importance is the finding that exposure to maternal depression in
infancy was not associated with risk for pure externalising
symptoms. None of the interaction terms including exposure in the infancy
period was significant (Table
3).
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Initial exposure in the toddler/pre-school period (age 2-4
years)
When children with pure forms of symptoms were combined with
those with co-occurring symptoms, initial exposure to maternal depression in
the toddler/pre-school period was associated with greater odds of being rated
by teachers as being in the high externalising group, but only for girls (OR
4.30, 95% CI 1.32-14.06, P=0.008) (see
Table 2). However, when girls
with high co-occurring symptoms were distinguished from those with
pure symptoms, initial exposure in the toddler/pre-school period
posed a risk for high levels of pure externalising symptoms (OR
9.03, 95% CI 2.16-37.71, P=0.002) but not for co-occurring symptoms
(OR 1.84, 95% CI 0.27-12.43, P=0.267). Exposure to maternal
depression in the toddler/pre-school period was not associated with risk for
high internalising symptoms, in either pure or co-occurring
forms. The interaction term including exposure in the toddler/pre-school
period and maternal education was not significant (see
Table 3).
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DISCUSSION |
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These findings support the idea that infancy may be a sensitive period for the occurrence of internalising symptoms later in childhood because it is an important time for the development of a secure motherinfant attachment, which in turn provides a framework for the infant's regulation of emotion (Campbell & Cohn, 1997). Maternal depression may impede achievement of these stage-salient tasks and have a longer-range impact on the child's affective, behavioural or cognitive development.
Initial exposure during the toddler/pre-school period
Our findings indicated that initial exposure to maternal depression in the
toddler/pre-school period increased the risk only of high pure
externalising symptoms in kindergarten, and then only among girls. This stands
in contrast to other studies that do not distinguish initial exposure during
this developmental period from episodes that began earlier, and which
generally find increased concurrent internalising and externalising symptoms.
However, caution must be exercised in interpreting this finding because the
cell sizes are small. Moreover, reports of gender differences in prior studies
on this subject have been inconsistent (reviewed by
Goodman & Gotlib,
1999).
Nevertheless, there is evidence in prior studies to suggest several plausible explanations for the risk in girls. Each is predicated on the assumption that girls identify more strongly with their mothers than do boys. To the extent that maternal depression may arise in the context of family stressors (Cicchetti et al, 1998) that are also known to be associated with externalising disorders (Fendrich et al, 1990) and accompanying increased irritability and harsher parenting (reviewed by Cummings & Davies, 1994; Goodman & Gotlib, 1999), girls may be especially likely to react with increased negativity. Further, it may be the change from maternal health and a secure relationship in infancy to maternal depression later that has a uniquely damaging effect on girls, who may be especially reactive to this shift.
The timing of maternal depression
Taken together, the findings suggest that the impact of maternal depression
may be more severe with earlier exposure
(Goodman & Gotlib, 1999). It is also possible that these effects are due to the persistence or
recurrence of maternal depression into the toddler/pre-school period, so that
it is the length of the exposure, rather than its timing, that is important
(Anderson & Hammen, 1993;
Campbell & Cohn, 1997;
NICHD Early Child Care Research Network,
1999). However, the results of the study did not change when we
took account of children who were exposed to maternal depression in both
periods. Although it is important to investigate this issue more fully, these
findings suggest that exposure in the infancy period does have important and
lasting effects on children's mental health symptoms, consistent with studies
such as those by Murray and colleagues
(Murray et al,
1999).
It is possible, of course, that children's difficult temperaments or emotional and behavioural problems precede the onset of maternal depression in the toddler/pre-school period. Although some studies have demonstrated that these are reciprocal and not one-way relationships (Hammen et al, 1991; Gotlib & Wheaton, 1997), others have shown that maternal depression affects children's symptoms independent of any effects of children on mothers (Murray et al, 1996).
The distinction between pure and co-occurring symptoms
The findings from this study underscore the importance of distinguishing
the co-occurring symptom group from those with pure forms. To
the extent that children exposed to maternal depression during infancy
experience disruptions in attachment and security, they may be especially
vulnerable to internalising problems as they negotiate the challenges of
developing new relationships with peers and teachers during the first year of
formal schooling. If disruptions in attachment also have interfered with
children's learning to regulate emotions, they may also be vulnerable to
externalising symptoms during this potentially stressful time. For girls
especially, initial exposure to maternal depression in the toddler/pre-school
period, when the stage-salient tasks are to develop autonomy and self-control,
may pose a special risk for pure externalising symptoms as new
social relationships and the structured setting of the kindergarten classroom
are encountered.
Unfortunately, in attempting to clearly define and measure child mental health symptoms, researchers have taken pains to distinguish internalising from externalising symptoms but have typically ignored their frequent co-occurrence (Zoccolillo, 1992). While pure forms of symptoms may often (but not always) have different aetiologies, their co-occurring forms may arise from problems of attachment and emotional dysregulation (Cole & Zahn-Waxler, 1992) originating in infancy.
The importance of distinguishing the co-occurring symptom group from the pure symptom groups is also emphasised when considering the direct influence of child gender and maternal education on children's symptom patterns. In this study boys were more likely to be in the high pure externalising group, possibly because externalising behaviours in their pure form are more normative for boys than for girls. In addition, children whose mothers had less education were more likely to have co-occurring symptoms. These results suggest that the associations between family socio-economic status and externalising symptoms found in other studies (Sinclair & Murray, 1998) may actually reflect an association between socio-economic status and co-occurring symptoms, rather than an association with externalising symptoms per se.
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Clinical Implications and Limitations |
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LIMITATIONS
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ACKNOWLEDGMENTS |
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REFERENCES |
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Alpern, L. & Lyons-Ruth, K. (1993) Preschool children at social risk: chronicity and timing of maternal depressive symptoms and child behaviour problems at school and at home. Development and Psychopathology, 5, 371-387.
American Psychiatric Association (1987) Diagnostic and Statistical Manual of Mental Disorders (3rd edn, revised) (DSMIIIR). Washington, DC: APA.
Anderson, C. A. & Hammen, C. L. (1993) Psychosocial outcomes of children of unipolar depressed, bipolar, medically ill, and normal women: a longitudinal study. Journal of Consulting and Clinical Psychology, 61, 448-454.[CrossRef][Medline]
Boyle, M. H., Offord, D. R., Racine, Y. A., et al (1993) Evaluation of the revised Ontario Child Health Study scales. Journal of Child Psychology and Psychiatry and Allied Disciplines, 34, 189-213.[Medline]
Campbell, S. B. & Cohn, J. F. (1997) The timing and chronicity of postpartum depression: implications for infant development. In Postpartum Depression and Child Development (eds L. Murray & P. Cooper), pp. 165-197. New York: Guilford.
Cicchetti, D., Rogosch, F. A. & Toth, S. L. (1998) Maternal depressive disorder and contextual risk: contributions to the development of attachment insecurity and behavior problems in toddlerhood. Development and Psychopathology, 10, 283-300.[CrossRef][Medline]
Cole, P. M. & Zahn-Waxler, C. (1992) Emotional dysregulation in disruptive behavior disorders. In Rochester Symposium on Development Psychopathology: Vol. 4. Developmental Perspectives on Depression (eds D. Cicchetti & S. L. Toth), pp. 173-209. Rochester, NY: University of Rochester Press.
Cummings, E. M. & Davies, P. T. (1994) Maternal depression and child development. Journal of Child Psychology and Psychiatry, 35, 73-112.[Medline]
Entwisle, D. R. & Alexander, K. L. (1989) Early schooling as a critical period phenomenon. In Sociology of Education and Socialization (Vol. 8) (eds K. Namboodiri & R. G. Corwin). Greenwich: JAl.
Essex, M. J., Boyce, W. T., Goldstein, L. H., et al (2001) The confluence of mental, physical, social, and academic difficulties in middle childhood: II. Developing the MacArthur Health and Behavior Questionnaire. Journal of the American Academy of Child and Adolescent Psychiatry, in press.
Fendrich, M., Warner, V. & Weissman, M. M. (1990) Family risk factors, parental depression, and psychopathology in offspring. Developmental Psychology, 26, 40-50.[CrossRef]
Fergusson, D. M., Horwood, L. J. & Lynskey, M. T. (1995) Maternal depressive symptoms and depressive symptoms in adolescents. Journal of Child Psychology and Psychiatry and Allied Disciplines, 36, 1161-1178.[Medline]
Field, T. (1992) Infants of depressed mothers. Development and Psychopathology, 4, 49-66.
Goodman, S. H. & Gotlib, I. H. (1999) Risk for psychopathology in the children of depressed mothers: a developmental model for understanding mechanisms of transmission. Psychological Review, 106, 458-490.[CrossRef][Medline]
Gotlib, I. H. & Wheaton, B. (eds) (1997) Stress and Adversity Over the Life Course: Trajectories and Turning Points. New York: Cambridge University Press.
Gotlib, I. H. & Goodman, S. H. (1999) Children of parents with depression. In Developmental Issues in the Clinical Treatment of Children and Adolescents (eds W. K. Silverman & T. H. Ollendick), pp. 415-432. New York: Allyn & Bacon.
Hammen, C., Burge, D. & Adrian, C. (1991) Timing of mother and child depression in a longitudinal study of children at risk. Journal of Consulting and Clinical Psychology, 59, 341-345.[CrossRef][Medline]
Hyde, J. S., Klein, M. H., Essex, M. J., et al (1995) Maternity leave and women's mental health. Psychology of Women Quarterly, 19, 257-285.
Lyons-Ruth, K. (1992) Maternal depressive symptoms, disorganized infantmother attachment relationships and hostile-aggressive behavior in the preschool classroom: a prospective longitudinal view from infancy to age five. In Rochester Symposium on Developmental Psychopathology; Vol. 4. Developmental Perspectives on Depression (eds D. Cicchetti & S. L. Toth), pp. 131-171. Rochester, NY: University of Rochester Press.
Murray, L., Fiori-Cowley, A. & Hooper, R. (1996) The impact of postnatal depression and associated adversity on early motherinfant interactions and later infant outcome. Child Development, 67, 2512-2526.[Medline]
Murray, L., Sinclair, D., Cooper, P., et al (1999) The socioemotional development of 5-year-old children of postnatally depressed mothers. Journal of Child Psychology and Psychiatry, 40, 1259-1271.[CrossRef][Medline]
NICHD Early Child Care Research Network (1999) Chronicity of maternal depressive symptoms, maternal sensitivity, and child functioning at 36 months. Developmental Psychology, 35, 1297-1310.[CrossRef][Medline]
Robins, L. N., Helzer, J. H., Croughan, J., et al (1981) National Institute of Mental Health Diagnostic Interview Schedule: its history, characteristics, and validity. Archives of General Psychiatry, 38, 381-389.[Abstract]
Sinclair, D. & Murray, L. (1998) Effects of postnatal depression on children's adjustment to school. Teacher's reports. British Journal of Psychiatry, 172, 58-63.[Abstract]
Zoccolillo, M. (1992) Co-occurrence of conduct disorder and its adult outcomes with depressive and anxiety disorders: a review. Journal of the American Academy of Child and Adolescent Psychiatry, 31, 547-556.[Medline]
Received for publication February 23, 2000. Revision received October 19, 2000. Accepted for publication October 19, 2000.
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