Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK
University of Toronto, Canada
Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK
Institute of Education, London, UK
Correspondence: Dr Thomas G. O'Connor, Departments of Psychology and Child/Adolescent Psychiatry, Institute of Psychiatry, III Denmark Hill, London SE5 8AF, UK. E-mail: spjwtoc{at}iop.kcl.ac.uk
Declaration of interest This study was funded by the Medical Research Council.
See editorial, pp.
9394, this issue.
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ABSTRACT |
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Aims To examine the sources of variation in children's behavioural and emotional problems across diverse family settings.
Method Levels of behavioural and emotional problems in children from diverse stepfamilies and single-parent families were compared with children living with both biological parents. Psychosocial risks were measured at the individual child and family levels.
Results Behavioural and emotional problems were elevated in children in stepmother/complex stepfamilies and single-parent families, but not in simple stepfather families, relative to biological families. Psychopathology associated with family type was explained by compromised quality of the parentchild relationship, parental depression and socio-economic adversity. Sibling similarity in behavioural and emotional problems was most pronounced in high-risk family settings.
Conclusions Family type is a proxy for exposure to psychosocial risks; the extent of family-wide influence on children's development may be strongest in high-stress settings.
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INTRODUCTION |
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A study of diverse family types provides an ideal context for assessing both the magnitude and the sources of between- and within-family variation in child psychopathology. The research design and data analyses allowed us to distinguish two opposing views on the impact of risks on children's psychopathology. On one hand, we examined the degree to which psychosocial risks, including family type, operated on a family-wide basis. On the other, we examined the hypothesis that psychosocial risks operated in a child-specific manner and, furthermore, that there would be significant within-family variation in children's behavioural and emotional problems across family types. The key conceptual and methodological point here is that a risk that is presumably shared by siblings membership of a non-traditional family may have systematic yet differential effects on siblings.
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METHOD |
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We included families with two or more children in the sampling procedure because we were especially interested in the differences between siblings in adjusting to family transitions. The representativeness of families within each of the four family types in ABSS was suggested by the finding that ABSS families did not differ from families of the same type in the large community sample in terms of maternal education, income and child adjustment. Overall, 83% of families who were eligible (based on the above criteria) agreed to participate. The age of the youngest child was 4.8 (s.d. 0.38) years and the age range of the siblings was 6-17 years (mean age 10.2 years, s.d. 2.9). The sample included a range of socio-economic levels.
Procedures and measures
The ABSS study began when the target child was approximately 4.5 years old.
Parents, step-parents and children over the age of 7 years (i.e. older
siblings of the target child) completed questionnaire and interview measures
in the family home; interviews were conducted by trained research
assistants.
Children's psychopathology
Parents completed the Strengths and Difficulties Questionnaire (SDQ;
Goodman, 1997), a revised
version of a widely used measure of behavioural problems for young children
(Elander & Rutter, 1996). The SDQ has several behavioural problem sub-scales, but these sub-scales were
combined in a total difficulties score because of the similarity
in results at the sub-scale level and because the scales are moderately to
highly intercorrelated.
Socio-economic status
The highest level of education achieved by mothers was categorised into
three commonly used distinctions (no/minimal qualifications, school-leaving
qualifications and university degree). Income was measured on a five-point
scale (1, less than £100 per week; 5, over £400 per week).
Maternal depression
Emotional well-being was reported by mothers using a modified version of
the Malaise Index (Rutter et al, 1970), a self-report measure of
depressive symptoms (=0.81). This measure has been used extensively in
previous research.
Parentchild relationship
Parentchild relationship measures were adapted from previously
validated scales (Hetherington &
Clingempeel, 1992; Dunn et
al, 1998). Frequency of parentchild conflict was
measured using a modified version of the Daily Routines scale (=0.86).
Frequency of talking to each child about what he or she had done wrong,
explaining rules and compromising, was measured using a modified version of
the Communication About Discipline scale (
=0.68). Frequency of
different types of punitive discipline techniques, such as yelling at or
ridiculing the child, was measured using a modified version of the Negative
Sanctions scale (
=0.66). Expressive and instrumental involvement with
each child was measured using the Expression of Affection scale
(
=0.83). Reports of enjoyment of spending time with each child were
assessed from the positive factor of the ParentChild Relationship scale
(
=0.90); parental criticism and nagging of the child were assessed
using the negative factor from the ParentChild Relationship scale
(
=0.82).
These six parenting scales were subjected to principal components analyses
(varimax rotation). Two factors emerged with eigenvalues greater than one,
explaining 59% of the total variance. The negativity factor (coercion,
hostility, punitiveness) was composed of the negative scale from the
ParentChild Relationship measure, the Negative Sanctions scale and the
Daily Routines scale ( for the factor scales=0.76). The positivity
factor (warmth, supportiveness, enjoyment of the child) included the
Expression of Affection scale, the positive scale from the ParentChild
Relationship measure and the Communication About Discipline measure (
for the factor scales=0.68).
Family type and biological relatedness of parents and children
Four family types were defined:
The rationale for using this coding of family type was based on several considerations. First, most research on stepfamilies to date has considered simple stepfather families, and we wished to have a comparable group of stepfamilies to compare with previous studies. Second, simple stepfather families constitute the vast majority of stepfamilies (Haskey, 1994). Third, there are important empirical differences between simple stepfather and other stepfamily types (see below). In addition to measuring family type, we also included a measure of biological relatedness between parent and child. This measure is not redundant with family type, because within stepfamilies children varied in their biological relatedness to the father.
Data analyses
An important methodological limitation of most studies of the risk and
protective factors for children's psychopathology is that only one child per
family is selected. The consequence of this is that the effects attributable
to family-level factors (e.g. parental psychopathology), individual
child-level factors (e.g. age, gender) and the interaction between the two are
completely confounded. A novel feature of the study was the use of multi-level
modelling (Bryk & Raudenbush,
1992; Goldstein,
1995; Goldstein et al,
1998), an analytic approach that capitalises on the nested or
hierarchical structure of family data. This approach partitions variation
attributable to each level in the data structure, which in the
current case are the family level (which we refer to as
between-family variation) and the individual child level (which we
refer to as within-family variation).
Three features of the multi-level model results are highlighted in Table 1. In the top section, we present the fixed effects associated with the predictor variables. These estimates and standard errors are interpreted as in a regression model; an estimate that is approximately twice its standard error has a significant (P < 0.05) association with child psychopathology. In the random effects section, error variance is decomposed into family-level (between-family) and individual child-level (within-family) variability. Estimates for the fixed and random effects are simultaneously calculated using a maximum likelihood procedure, the value of which is also presented. It is important to note that the estimates included in the random effects section of the table are not interpreted in the same way as the estimates for the fixed effects. The estimates in the random effects section are estimates of variance.
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For the fixed and random effects parameters, family type was dummy coded with biological (or non-step) families as the control condition. Thus, in Table 1, the regression coefficients (for fixed effects) and variance estimates (for random effects) indicate the relative difference compared with biological families. For example, in model 2, the family-level variance for stepmother/complex stepfamilies is the sum of the variances for biological (control) families plus the estimate for stepmother/ complex stepfamilies, 0.17+0.21 (Table 1). Finally, in order to include children in single-parent families and to avoid data loss from non-response by fathers, we used only mothers' parenting in the analyses below. For each measure listed above the percentage of missing data was slight, but this rate was exaggerated when accumulated across many variables. In order to avoid problems with missing data in the final multivariate analysis, we used a mean substitution method for dealing with missing data.
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RESULTS |
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Allowing the family type coefficients to vary at the family and individual
level (model 2 in Table 1) was
associated with an improved fit of the model (change, 2(6)=14,
P<0.05). An examination of the random effects parameters indicated
that children in stepfather families showed significantly more individual
child-level (or within-family) variability than children in biological
families. The within-family variance for children in stepmother/complex or
single families was not significantly different from intact families.
Stepfather, stepmother/complex and single families did not show significantly
greater family-level variability compared with biological families. This means
that the mean level of emotional and behavioural problems shown by children in
these different family types is not more varied than the mean level of
problems shown by children in biological families.
Mediators of behavioural and emotional problems
Models 2 to 5 display the estimates of fixed and random effects as more
explanatory variables are added to the equation. In model 3, key family-level
risks are added: two indices of socio-economic adversity, and maternal
depression. In model 4, child-level variables of age, gender and biological
relatedness to mother and father are included. Model 4 also includes the
central child-level variable: quality of parentchild relationship.
Model 5 adds interactions between and within levels. At each stage, the
increase in model fit is significant, based on the change in value with the
decrease in degrees of freedom (distributed as a 2).
Three features stand out from the models in Table 1. First, the impact of the explanatory variables diminished as variables were added to the equation, demonstrating that these risks do not act in isolation. In particular, family type per se did not explain variability in child psychopathology once hypothesised risks were statistically controlled. This can be seen by examining the way in which the coefficients for stepmother/complex and single-parent families became non-significant between model 3 and model 4 when parenting variables were entered into the equation. The interaction suggested that family type moderates proximal risks: parentchild negativity had a greater effect in biological families than in stepmother/complex stepfamilies. The age x parentchild negativity interaction indicates that the strength of the connection between negativity and behavioural/emotional problems increases with age.
Second, it is possible to calculate intraclass correlations according to family type. Intraclass correlation, defined as the percentage of family-level variance to total variance, indexes the relative similarity of the two or more siblings within a family, compared with two children chosen randomly. From the results in model 5, the intraclass correlation for biological (control) families is [0.13/(0.13+0.27)]=0.33; for stepfather families the intraclass correlation is (0.13-0.07)/[(0.013-0.07)+(0.27+0.18)]=0.12; for stepmother/complex stepfamilies it is (0.13+0.19)/[0.13+0.19)+(0.27+0.08)]=0.48; for single-parent families it is (0.13+0.10)/[(0.13+0.10)+(0.27-0.02)]=0.48. The implication is that family membership may have more of an impact on psychopathology in stepmother/complex and single-parent families than in stepfather and biological families. However, because there were no significant family type differences in family-level variance and only one significant difference in child-level variance across family types, differences in intraclass correlations should be considered as trends rather than as reliable differences.
Third, a novel feature of this approach to studying families is that it allows us to evaluate changes in family-level and child-level effects as variables measured at these levels are entered into the model. The pattern of between-family and within-family variance continued to differ according to family type once explanatory variables were included. As explanatory variables enter the model, the intraclass correlation changes, and it may change differentially for different family types. These effects can be seen by comparing Figs 1 and 2.
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DISCUSSION |
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Documenting variability in children's behavioural/emotional problems following exposure to stress and understanding who is vulnerable is a basic requirement for research on risk and resilience (Cicchetti & Cohen, 1995). The current findings extend previous observations about the tremendous variability in children's adjustment to marital transitions in two ways. First, increased variation in child psychopathology was observed at both the individual child level (increased within-family variation) and the family level (increased between-family variation). We draw attention to this overall pattern, although the specific comparisons were significant in only a minority of cases. Second, although both individual child-level and family-level variance were reduced substantially once key mediating risks were included in the model, the differences between family types were retained (but much reduced). That is, although we were able to account for mean differences in behavioural and emotional problems according to family type, we were unable to account entirely for variance differences. The implication is that there may be risk factors that accentuate variability in psychopathology in non-traditional families without necessarily increasing mean level of disturbance.
Do risk factors operate on an individual or family-wide basis?
A challenge for family researchers has been to document not only the risks
for children's behavioural and emotional problems, but also the mechanisms by
which they operate. Recent debates have focused particularly on whether
identified risk factors operate on an individual or on a family-wide basis
(Deal et al, 1994;
Plomin, 1994;
Rutter et al, 1999).
By separating family-level from individual child-level risks, the multi-level
model approach provides clarity on the nature of risk processes for children's
psychopathology. Results in Table
1 reveal that child-specific risks explained child-level or
within-family variation, whereas family-wide or between-family risks explained
between-family variation.
What is a particularly novel finding is that a risk measured at the family level family type could affect children in the same family differently. This was illustrated by the increased child-level variance across family types, particularly in the stepfather families. Similarly, the interaction between a family-level variable family type and a child-level variable parentchild negativity highlights the need to consider specific factors that shape siblings' different responses to a shared risk. Further research using this conceptual and methodological approach may explain why children in the same family are not similarly vulnerable to stresses presumed to affect the whole family. An important lesson from these analyses is that identifying risks provides no necessary clues as to their mode of operation. Risks measured at the family level may not operate on a family-wide basis, and risks measured at the individual child level may have family-wide effects.
In addition to highlighting the importance of within-family variation in children's behavioural and emotional problems, these findings also demonstrate the equally important and more novel point that some risks do appear to operate in a family-wide manner. The finding that there is a shared or family-wide effect is most clearly demonstrated by the patterns of intraclass correlations. Sibling resemblance (i.e. the magnitude of intraclass correlation) was greatest in family types that appear to be experiencing the most adverse circumstances: single-parent families and stepmother/complex stepfamilies. The implication is that a stressful environment may have family-wide effects, increasing the level of psychopathology for all children rather than (or in addition to) specific children within the family. It seems unlikely that genetic similarity among siblings could entirely account for the family-wide effect. If genetic relatedness were a major factor, then we would expect proportionately greater family-level variance in families with the highest degree of biological relatedness. In fact, stepmother/complex families, which had the greatest intraclass correlation, included the highest percentage of half-siblings and unrelated siblings.
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Clinical Implications and Limitations |
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LIMITATIONS
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REFERENCES |
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Bryk, A. S. & Raudenbush, S. W. (1992) Hierarchical Linear Models. London: Sage Publications.
Cicchetti, D. & Cohen, D. (1995) Developmental Psychopathology: Vol. I. Theory and Method. New York: John Wiley and Sons.
Deal, J., Halverson, C. F. & Wampler, K. S. (1994) Sibling similarity as an individual differences variable: within-family measures of shared environment. In Separate Social Worlds of Siblings: The Impact of Nonshared Environment on Development (eds E. M. Hetherington, D. Reiss & R. Plomin), pp. 205-218. Rahwah, NJ: Lawrence Erlbaum.
Dunn, J., Deater-Deckard, K., Pickering, K., et al (1998) Children's adjustment and prosocial behavior in step-, single, and nonstep-family settings: findings from a community study. Journal of Child Psychology and Psychiatry, 39, 1083-1095.[CrossRef][Medline]
Elander, J. & Rutter, M. (1996) Use and development of the Rutter parents' and teachers' scales. International Journal of Methods in Psychiatric Research, 6, 63-78.[CrossRef]
Golding, J. (1996) Children of the Nineties: a resource for assessing the magnitude of long-term effects of prenatal and perinatal events. Contemporary Reviews in Obstetrics and Gynaecology, 8, 89-92.
Goldstein, H. (1995) Multilevel Statistical Models. London: Edward Arnold.
Goldstein, H., Rasbash, J., Plewis, I., et al (1998) A User's Guide to MLwiN. London: Institute of Education.
Goodman, R. (1997) The Strengths and Difficulties Questionnaire: a research note. Journal of Child Psychology and Psychiatry, 38, 581-586.[Medline]
Haskey, J. (1994) Stepfamilies and stepchildren in Great Britain. Population Trends, 17-28.
Hetherington, E. M. & Clingempeel, W. G. (1992) Coping with marital transitions: a family systems perspective. Monographs of the Society for Research in Child Development, 57, 2-3.
Hetherington, E. M., Bridges, M. & Insabella, G. M. (1998) What matters? What does not? Five perspectives on the association between marital transitions and children's adjustment. American Psychologist, 53, 167-184.[CrossRef][Medline]
Plomin, R. (1994) Genetics and Experience. London: Sage Publications.
Plomin, R. & Daniels, D. (1987) Why are children in the same family so different from one another? Behavioral and Brain Sciences, 10, 1-16.
Plomin, R., Tizard, J. & Whitmore, K. (1970) Education, Health and Behaviour. London: Longman.
Rutter, M., Silberg, J., O'Connor, T., et al (1999) Genetics and child psychiatry: II. Empirical research findings. Journal of Child Psychology and Psychiatry, 40, 19-55.[CrossRef][Medline]
Received for publication June 19, 2000. Revision received September 25, 2000. Accepted for publication September 25, 2000.
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