Examining whether offspring psychopathology influences illness course in mothers with recurrent depression using a high-risk longitudinal sample

Depression is known to be influenced by psychosocial stressors. For mothers with recurrent depressive illness, the presence of psychopathology in their children may have important effects on their own mental health. Although the impact of maternal depression on child mental health is well-established, no study to date, as far as we are aware, has examined the extent to which offspring psychopathology influences the course of depression in mothers with a history of recurrent depressive illness, what types of child psychopathology impact maternal mental health, or whether risks vary by child gender. Aims were to (a) Use a longitudinal design to examine whether adolescent psychopathology (depression, disruptive behavior disorder; DBD) predicts recurrence of a depressive episode and depression symptom course in women with a history of recurrent depression; and (b) To test if observed effects vary by child gender. 299 mothers with recurrent major depressive disorder and their adolescent offspring were assessed on 2 occasions, 29 months apart. Maternal depression and offspring psychopathology were assessed using semistructured interview measures. Cross-generational links across time were assessed using structural equation modeling. Analyses were adjusted for past severity of maternal depression. Offspring depression symptoms but not DBD symptoms at baseline predicted future episode recurrence in mothers. Depression symptoms in daughters (β = .16, p = .039) but not sons (β = −.07, p = .461), predicted an increase in maternal depression symptoms across time. Psychopathology in daughters is associated with long-term depressive symptoms in women (mothers) with a history of recurrent depression. Findings highlight the importance of careful assessment and management of mental health problems in adolescents for more effective management of maternal depression. This study suggests that offspring symptoms of depression may be important for the recurrence of maternal depression episodes. Girls’ symptoms of depression may be a particularly important psychosocial stressor for the development of depressive symptoms in mothers with a history of recurrent depression.

This study suggests that offspring symptoms of depression may be important for the recurrence of maternal depression episodes. Girls’ symptoms of depression may be a particularly important psychosocial stressor for the development of depressive symptoms in mothers with a history of recurrent depression.

Identifying key parent-reported symptoms for detecting depression in high risk adolescents

Adolescent offspring of depressed parents are at particularly heightened risk of developing early onset Major Depressive Disorder (MDD) yet are unlikely to access services. We therefore aimed to identify a parsimonious combination of parent-reported symptoms that accurately detected offspring MDD. We used a multi-sample study comprising a development sample of 335 offspring of adults with recurrent MDD assessed on three occasions (mean age 12.4-14.8 years) and an independent validation sub-sample of 807 adolescents from a general population cohort (mean age 13.1 years). Parent ratings of psychiatric symptoms in adolescent offspring were assessed using established questionnaires. The best performing four-item combination of symptoms was identified. Accuracy in detecting concurrent DSM-IV MDD diagnosis, assessed by direct adolescent and parent interviews, was compared to the well-established 13-item short Moods and Feelings Questionnaire (sMFQ) using ROC curve analysis. The combination identified (concentration problems, anhedonia, worrying excessively and feeling unloved) performed equivalently to the sMFQ both in the development dataset and in the validation dataset. We concluded that a combination of four parent-reported mental health items performs equivalently to an established, longer depression questionnaire measure in detecting a diagnosis of adolescent major depressive disorder among offspring of parents with recurrent MDD and needs further evaluation.

Exploring the longitudinal association between interventions to support the transition to secondary school and child anxiety

School transition at around 11-years of age can be anxiety-provoking for children, particularly those with special educational needs (SEN). The present study adopted a longitudinal design to consider how existing transition strategies, categorized into cognitive, behavioral or systemic approaches, were associated with post-transition anxiety amongst 532 typically developing children and 89 children with SEN. Multiple regression analysis indicated that amongst typically developing pupils, systemic interventions were associated with lower school anxiety but not generalized anxiety, when controlling for prior anxiety. Results for children with SEN differed significantly, as illustrated by a Group × Intervention type interaction. Specifically, systemic strategies were associated with lower school anxiety amongst typically developing children and higher school anxiety amongst children with SEN. These findings highlight strategies that schools may find useful in supporting typically developing children over the transition period, whilst suggesting that children with SEN might need a more personalized approach.

A longitudinal study of self-control at the transition to secondary school: Considering the role of pubertal status and parenting

Higher self-control in children and adolescents is associated with a range of positive outcomes in adulthood. However, little is known about the naturalistic development of self-control during early adolescence and the factors that affect this. We examined the role of puberty and parenting style as theoretically important influences on stability and change in self-control. A longitudinal (3 waves), multiple-informant dataset of children entering early adolescence (M = 11 years) was used to explore longitudinal change in self-control using latent growth curve modelling. Children's self-control declined during the one-year study period and declines were associated with children's behavioural and social functioning. Associations with self-control were found for pubertal status and parental warmth and hostility, but not for parental discipline. The findings suggest that during early adolescence, when children make the transition to secondary school, self-control declines. This is particularly the case for those experiencing puberty earlier than their peers. Parent warmth influences the trajectory of self-control during this period.

Profiling depression in childhood and adolescence: the role of conduct problems

BACKGROUND

Depression is typically more common in females and rates rise around puberty. However, studies of children and adolescents suggest that depression accompanied by conduct problems may represent a different subtype not characterised by a female preponderance, with differing risk factors and genetic architecture compared to pure-depression. This study aimed to identify aetiologically distinct profiles of depressive symptoms, distinguished by the presence or absence of co-occurring conduct problems.

METHODS

Latent profile analysis was conducted on a school sample of 1648 children (11-12 years) and replicated in a sample of 2006 twins (8-17 years).

RESULTS

In both samples pure-depressive and conduct-depressive profiles were identified. The pure-depressive profile was associated with female gender, while the conduct-depressive profile was associated with lower cognitive ability but not with gender. Twin analyses indicated possible differences in genetic aetiology.

CONCLUSIONS

There was evidence for aetiologically heterogeneous depression symptom profiles based on the presence or absence of co-occurring conduct problems.

Mental health resilience in the adolescent offspring of parents with depression: a prospective longitudinal study

BACKGROUND

Young people whose parents have depression have a greatly increased risk of developing a psychiatric disorder, but poor outcomes are not inevitable. Identification of the contributors to mental health resilience in young people at high familial risk is an internationally recognised priority. Our objectives were to identify protective factors that predict sustained good mental health in adolescents with a parent with depression and to test whether these contribute beyond what is explained by parent illness severity.

METHODS

The Early Prediction of Adolescent Depression study (EPAD) is a prospective longitudinal study of offspring of parents with recurrent depression. Parents with recurrent major depressive disorder, co-parents, and offspring (aged 9-17 years at baseline) were assessed three times over 4 years in a community setting. Offspring outcomes were operationalised as absence of mental health disorder, subthreshold symptoms, or suicidality on all three study occasions (sustained good mental health); and better than expected mental health (mood and behavioural symptoms at follow-up lower than predicted given severity of parental depression). Family, social, cognitive, and health behaviour predictor variables were assessed using interview and questionnaire measures.

FINDINGS

Between February and June, 2007, we screened 337 families at baseline, of which 331 were eligible. Of these, 262 completed the three assessments and were included in the data for sustained mental health. Adolescent mental health problems were common, but 53 (20%) of the 262 adolescents showed sustained good mental health. Index parent positive expressed emotion (odds ratio 1·91 [95% CI 1·31-2·79]; p=0·001), co-parent support (1·90 [1·38-2·62]; p<0·0001), good-quality social relationships (2·07 [1·35-3·18]; p=0·001), self-efficacy (1·49 [1·05-2·11]; p=0·03), and frequent exercise (2·96 [1·26-6·92]; p=0·01) were associated with sustained good mental health. Analyses accounting for parent depression severity were consistent, but frequent exercise only predicted better than expected mood-related mental health (β=-0·22; p=0·0004) not behavioural mental health, whereas index parents' expression of positive emotions predicted better than expected behavioural mental health (β=-0·16; p=0·01) not mood-related mental health. Multiple protective factors were required for offspring to be free of mental health problems (zero or one protective factor, 4% sustained good mental health; two protective factors, 10%; three protective factors, 13%, four protective factors, 38%; five protective factors, 48%).

INTERPRETATION

Adolescent mental health problems are common, but not inevitable, even when parental depression is severe and recurrent. These findings suggest that prevention programmes will need to enhance multiple protective factors across different domains of functioning.

FUNDING

Sir Jules Thorn Charitable Trust, Economic and Social Research Council.

Examining reward-seeking, negative self-beliefs and over-general autobiographical memory as mechanisms of change in classroom prevention programs for adolescent depression

BACKGROUND

Effective methods to prevent adolescent depressive symptoms could reduce suffering and burden across the lifespan. However, psychological interventions delivered to adolescents show efficacy only in symptomatic or high-risk youth. Targeting causal risk factors and assessing mechanistic change can help devise efficacious universal or classroom based prevention programs.

METHODS

A non-randomized longitudinal design was used to compare three classroom-based prevention programs for adolescent depression (Behavioral Activation with Reward Processing, "Thinking about Reward in Young People" (TRY); Cognitive Behavioral Therapy (CBT) and Mindfulness Based Cognitive Therapy (MBCT)), and determine cognitive mechanisms of change in these programs. Cognitive mechanisms examined were reward-seeking, negative self-beliefs (assessed with behavioral tasks) and over-general autobiographical memory. 256 healthy adolescents aged 13-14 participated with 236 (92%) and 227 (89%) completing the pre- and post-assessments.

RESULTS

TRY was the only intervention associated with a reduction in depressive symptoms at follow-up. Reward-seeking increased following TRY. In the other programs there were non-significant changes in cognitive mechanisms, with more reflective negative self-beliefs in CBT and fewer over-general autobiographical memories in MBCT In the TRY program, which focused on increasing sensitivity to rewarding activities, reward seeking increased and this was associated with decreased depressive symptoms.

LIMITATIONS

Due to the infeasibility of a cluster randomized controlled trial, a non-randomized design was used.

CONCLUSIONS

Increased reward-seeking was associated with decreased depressive symptoms and may be a mechanism of depressive symptom change in the intervention with a focus on enhancing sensitivity and awareness of reward. This study provides preliminary evidence to suggest that incorporating activities to enhance reward sensitivity may be fruitful in randomized controlled trials of universal prevention programs for depression.

Longitudinal symptom course in adults with recurrent depression: Impact on impairment and risk of psychopathology in offspring

BACKGROUND

Major depressive disorder (MDD) is common and is associated with an increased risk of psychopathology in offspring. However, depression shows considerable heterogeneity in its course over time. The aim of this study is to examine the relationship between parent depression symptom trajectories and (i) quality of life and social impairment and (ii) psychiatric disorder and depression symptoms in their offspring.

METHOD

Participants were from a longitudinal study of 337 parents with recurrent MDD and their adolescent offspring. Families were assessed on three occasions over four years. Parent depressive symptoms and current MDD diagnosis were assessed using the Schedules for Clinical Assessment in Neuropsychiatry. Adult quality of life and social impairment were derived from the EuroQol and current employment status. Psychiatric outcomes in offspring were assessed using the Child and Adolescent Psychiatric Assessment.

RESULTS

Using latent class growth analysis, three distinct classes of parental depression symptoms were identified (asymptomatic, mild, and chronic high). Parent depression classes were associated with their own quality of life and social impairment, and with psychiatric disorder and depression symptoms in their offspring.

LIMITATIONS

(i) We were unable to test associations with specific offspring disorders, (ii) we did not address the direction of effects underlying associations, and (iii) the sample consisted primarily of mothers and findings may not generalise to depressed fathers.

CONCLUSION

Longitudinal assessments of depressive symptoms in parents could help to identify families who are most in need of early intervention.

Affective bias and current, past and future adolescent depression: a familial high risk study

BACKGROUND

Affective bias is a common feature of depressive disorder. However, a lack of longitudinal studies means that the temporal relationship between affective bias and depression is not well understood. One group where studies of affective bias may be particularly warranted is the adolescent offspring of depressed parents, given observations of high rates of depression and a severe and impairing course of disorder in this group.

METHODS

A two wave panel design was used in which adolescent offspring of parents with recurrent depression completed a behavioural task assessing affective bias (The Affective Go/No Go Task) and a psychiatric interview. The affective processing of adolescents with current, prior and future depressive disorder was compared to that of adolescents free from disorder.

RESULTS

Adolescents with current depression and those who developed depression at follow-up made more commission errors for sad than happy targets compared to adolescents free from disorder. There was no effect of prior depression on later affective processing.

LIMITATIONS

Small cell sizes meant we were unable to separately compare those with new onset and recurrent depressive disorder.

CONCLUSIONS

Valence-specific errors in behavioural inhibition index future vulnerability to depression in adolescents already at increased risk and may represent a measure of affective control. Currently depressed adolescents show a similar pattern of affective bias or deficits in affective control.

A longitudinal high-risk study of adolescent anxiety, depression and parent-severity on the developmental course of risk-adjustment

BACKGROUND

Adolescence is associated with developments in the reward system and increased rates of emotional disorders. Familial risk for depression may be associated with disruptions in the reward system. However, it is unclear how symptoms of depression and anxiety influence the development of reward-processing over adolescence and whether variation in the severity of parental depression is associated with hyposensitivity to reward in a high-risk sample.

METHODS

We focused on risk-adjustment (adjusting decisions about reward according to the probability of obtaining reward) as this was hypothesized to improve over adolescence. In a one-year longitudinal sample (N = 197) of adolescent offspring of depressed parents, we examined how symptoms of depression and anxiety (generalized anxiety and social anxiety) influenced the development of risk-adjustment. We also examined how parental depression severity influenced adolescent risk-adjustment.

RESULTS

Risk-adjustment improved over the course of the study indicating improved adjustment of reward-seeking to shifting contingencies. Depressive symptoms were associated with decreases in risk-adjustment over time while social anxiety symptoms were associated with increases in risk-adjustment over time. Specifically, depression was associated with reductions in reward-seeking at favourable reward probabilities only, whereas social anxiety (but not generalized anxiety) led to reductions in reward-seeking at low reward probabilities only. Parent depression severity was associated with lowered risk-adjustment in offspring and also influenced the longitudinal relationship between risk-adjustment and offspring depression.

CONCLUSIONS

Anxiety and depression distinctly alter the pattern of longitudinal change in reward-processing. Severity of parent depression was associated with alterations in adolescent offspring reward-processing in a high-risk sample.

Reported child awareness of parental depression

Aims and method To determine rates of parent-reported child awareness of parental depression, examine characteristics of parents, children and families according to child awareness, and explore whether child awareness is associated with child psychopathology. Data were available from 271 families participating in the Early Prediction of Adolescent Depression (EPAD) study, a longitudinal study of offspring of parents with recurrent depression.

Results Seventy-three per cent of participating children were perceived as being aware of their parent’s depression. Older children, and children of parents who experienced more severe depression, were more likely to be aware. Awareness was not associated with child psychopathology.

Clinical implications Considering children in the context of parental depression is important. Child awareness may influence their access to early intervention and prevention programmes. Further research is needed to understand the impact of awareness on the child.

The relationship between emotional problems and subsequent school attainment: a meta-analysis

Longitudinal studies have provided mixed findings regarding the relationship between emotional problems and subsequent poor school attainment. A meta-analysis of 26 community-based studies of children and adolescents was performed. Results revealed a prospective association between emotional problems and poor school attainment. More consistent associations were found for depression than anxiety. Moderator analyses indicated that some of the heterogeneity between studies may be due to age and gender, with reduced heterogeneity particularly notable for school grades during early adolescence and for anxiety by gender. Findings suggest that early identification and provision of support for young people with emotional problems may be helpful for improving academic outcomes such as school attainment.

The Depression Impairment Scale for Parents (DISP): a new scale for the measurement of impairment in depressed parents

Children of depressed parents are at increased risk of developing mood disorders but mechanisms of intrafamilial transmission are currently unclear. One rarely investigated area is the impact of depression on a parent's everyday functioning. Currently there are no validated assessments of depression-specific parental impairment. The creation of such a measure would complement depression symptom counts, providing a more comprehensive account of the parent's depression. We therefore aimed to develop a valid and reliable measure of impairment specifically associated with parental depression. In a longitudinal study of parents with recurrent unipolar depression and their offspring, we collected data from 337 parents. These participants completed the Depression Impairment Scale for Parents (DISP), a questionnaire assessing depression-associated impairment in multiple domains of functioning. Factor analysis revealed that this measure consisted of two factors - impairment in routine tasks/activities and impairment in family functioning - that together accounted for 51.04% of variance. The scale evidenced good internal consistency (Cronbach's alpha=0.82). The DISP also displayed good construct and criterion validity as evidenced by significant associations with established measures of depression severity and global impairment. These results demonstrate that the DISP is a valid and reliable measure of depression-associated impairment in parents.

Specific parental depression symptoms as risk markers for new-onset depression in high-risk offspring

OBJECTIVE

To disaggregate the depression construct and investigate whether specific depression symptoms in parents with a history of recurrent depression are clinical risk markers for future depression in their high-risk offspring. Our hypothesis was that parental symptoms of the type that might impact offspring would most likely be of greatest importance.

METHOD

Data were drawn from a longitudinal high-risk family study. Families were mainly recruited from primary care and included 337 parent-child dyads. Parents had a history of recurrent DSM-IV unipolar depression and were aged 26-55 years. Their offspring (197 female and 140 male) were aged 9-17 years. Three assessments were conducted between April 2007 and April 2011. Ninety-one percent of families (n = 305) provided full interview data at baseline and at least 1 follow-up, of which 291 were included in the primary analysis. The main outcome measure was new-onset DSM-IV mood disorder in the offspring, which was assessed using the Child and Adolescent Psychiatric Assessment.

RESULTS

Of the 9 DSM-IV depression symptoms, parental change in appetite or weight, specifically loss of appetite or weight, most strongly predicted new-onset mood disorder (odds ratio [OR] = 4.47; 95% CI, 2.04-9.79; P < .001) and future depression symptoms in the offspring (β = 0.12; B = 0.21; 95% CI, 0.00-0.42; P = .050). The cross-generational association was not accounted for by measures of parental depression severity (total depression symptom score, episode recurrence, age at onset, and past impairment or hospitalization) or other potential confounds (parent physical health, eating disorder, or medication).

CONCLUSIONS

Findings from this study suggest that loss of appetite or weight in parents with a history of recurrent depression is a marker of risk for depression in their offspring. The findings highlight the importance of examining depression heterogeneity. The biological and environmental mechanisms underlying this finding require investigation.

A longitudinal study of psychological functioning and academic attainment at the transition to secondary school

This longitudinal study of adolescents in the first year of secondary school, examined the relationship between psychological functioning at the beginning of year 7 (mean age 11.25 years) with attainment at the end of year 7 (mean age 11.78 years). Depressive symptoms, school liking and conduct problems predicted lower attainment across time having controlled for the temporal stability in psychological functioning and attainment. School concerns predicted lower attainment for boys only, and the effects of depressive symptoms on later attainment were significantly stronger for boys compared to girls. School liking - and school concerns for boys - remained significant predictors of attainment when controlling for conduct problems. The transition to secondary school may represent a window of opportunity for developing interventions aimed at improving both pupil psychological functioning and attainment.

Risk of psychopathology in adolescent offspring of mothers with psychopathology and recurrent depression

BACKGROUND

Offspring of mothers with depression are at heightened risk of psychiatric disorder. Many mothers with depression have comorbid psychopathology. How these co-occurring problems affect child outcomes has rarely been considered.

AIMS

To consider whether the overall burden of co-occurring psychopathology in mothers with recurrent depression predicts new-onset psychopathology in offspring.

METHOD

Mothers with recurrent depression and their adolescent offspring (9-17 years at baseline) were assessed in 2007 and on two further occasions up to 2011. Mothers completed questionnaires assessing depression severity, anxiety, alcohol problems and antisocial behaviour. Psychiatric disorder in offspring was assessed using the Child and Adolescent Psychiatric Assessment.

RESULTS

The number of co-occurring problems in mothers (0, 1 or 2+) predicted new-onset offspring disorder (odds ratio (OR) = 1.80, 95% CI 1.17-2.77, P = 0.007). Rates varied from 15.7 to 34.8% depending on the number of co-occurring clinical problems. This remained significant after controlling for maternal depression severity (OR = 1.73, 95% CI 1.03-2.89, P = 0.040).

CONCLUSIONS

The burden of co-occurring psychopathology among mothers with recurrent depression indexes increased risk of future onset of psychiatric disorder for offspring. This knowledge can be used in targeting preventive measures in children at high risk of psychiatric disorder.

'The risks of playing it safe': a prospective longitudinal study of response to reward in the adolescent offspring of depressed parents

BACKGROUND

Alterations in reward processing may represent an early vulnerability factor for the development of depressive disorder. Depression in adults is associated with reward hyposensitivity and diminished reward seeking may also be a feature of depression in children and adolescents. We examined the role of reward responding in predicting depressive symptoms, functional impairment and new-onset depressive disorder over time in the adolescent offspring of depressed parents. In addition, we examined group differences in reward responding between currently depressed adolescents, psychiatric and healthy controls, and also cross-sectional associations between reward responding and measures of positive social/environmental functioning. Method We conducted a 1-year longitudinal study of adolescents at familial risk for depression (n = 197; age range 10-18 years). Reward responding and self-reported social/environmental functioning were assessed at baseline. Clinical interviews determined diagnostic status at baseline and at follow-up. Reports of depressive symptoms and functional impairment were also obtained.

RESULTS

Low reward seeking predicted depressive symptoms and new-onset depressive disorder at the 1-year follow-up in individuals free from depressive disorder at baseline, independently of baseline depressive symptoms. Reduced reward seeking also predicted functional impairment. Adolescents with current depressive disorder were less reward seeking (i.e. bet less at favourable odds) than adolescents free from psychopathology and those with externalizing disorders. Reward seeking showed positive associations with social and environmental functioning (extra-curricular activities, humour, friendships) and was negatively associated with anhedonia. There were no group differences in impulsivity, decision making or psychomotor slowing.

CONCLUSIONS

Reward seeking predicts depression severity and onset in adolescents at elevated risk of depression. Adaptive reward responses may be amenable to change through modification of existing preventive psychological interventions.

Do parents know best? Parent-reported vs. child-reported depression symptoms as predictors of future child mood disorder in a high-risk sample

BACKGROUND

Parents with depression are thought to be unreliable reporters of children's depression symptoms, but findings are contradictory and primarily focus on discrepancies between parent and child reports rather than on the predictive validity of informants. Using a sample of parents with recurrent depression, our analyses utilised data from a prospective high-risk longitudinal study (the Early Prediction of Adolescent Depression study) to investigate whether baseline parental reports of child depression symptoms predicted new onset mood disorder (NOMD) in children.

METHODS

The sample included 287 parents with a history of recurrent depression and their adolescent offspring (aged 9-17 at baseline). Families were assessed at three time points. The Child and Adolescent Psychiatric assessment (parent and child versions) was used to assess the number of child depression symptoms (computed separately by informant at baseline) and NOMD at follow-up. All DSM-IV diagnoses were confirmed by two child psychiatrists.

RESULTS

Parent reports of child depression symptoms at baseline significantly predicted NOMD in children. Secondary analyses stratifying the sample according to child age showed that, for younger children, parent reports were significantly better at predicting NOMD compared to child reports. For children aged 12 or older, there were no significant differences between parent and child reports in predicting NOMD. The pattern of association remained the same once we controlled for baseline levels of parental depression.

LIMITATIONS

Not all parents were currently experiencing an episode of depression at the baseline assessments; the sample consisted predominantly of mothers, thus findings may not be applicable to fathers or families without a history of parental depression.

CONCLUSIONS

In this high risk sample, child and parent ratings of depression predict new onset child mood disorder to a similar degree. Clinicians and researchers should give due consideration to parent ratings of their children's depression symptoms, regardless of whether the parent suffers with depression.

Missed opportunities: mental disorder in children of parents with depression

BACKGROUND

Emerging evidence suggests that early intervention and prevention programmes for mental health problems in the offspring of parents with depression are important. Such programmes are difficult to implement if children with psychiatric disorder are not identified and are not accessing services, even if their parents are known to primary care.

AIM

To investigate service use in children of parents who have recurrent depression, and factors that influence such contact.

DESIGN AND SETTING

A total of 333 families were recruited, mainly through primary health care, in which at least one parent had received treatment for recurrent depression and had a child aged 9-17 years.

METHOD

Psychiatric assessments of parents and children were completed using research diagnostic interviews. The service-use interview recorded current (in the 3 months prior to interview) and lifetime contact with health, educational, and social services due to concerns about the child's emotions or behaviour.

RESULTS

Only 37% of children who met criteria for psychiatric disorder were in contact with any service at the time of interview. A third, who were suicidal or self-harming and had a psychiatric disorder at that time, were not in contact with any service. Lack of parental worry predicted lower service use, with higher rates in children with comorbidity and suicidality.

CONCLUSION

Most children with a psychiatric disorder in this high-risk sample were not in contact with services. Improving ease of access to services, increasing parental and professional awareness that mental health problems can cluster in families, and improving links between adult and child services may help early detection and intervention strategies for the offspring of parents with depression.

A longitudinal study of processes predicting the specificity of autobiographical memory in the adolescent offspring of depressed parents

Deficits in specific autobiographical memory retrieval are closely associated with depression. The ability to retrieve specific autobiographical memories develops throughout childhood and adolescence and is associated with adolescent depression within and across time. Studying young samples before they first experience depression provides an approach for testing processes that underlie reduced autobiographical memory specificity. This study is the first to examine the longitudinal association of rumination and executive function with autobiographical memory specificity in a sample of adolescents at elevated risk for future depression. A total of 259 adolescents (aged between 10 and 18 years) completed the Autobiographical Memory Test at baseline and 1-year follow-up. Measures of rumination, executive function, and depressive symptoms were obtained at baseline. The interaction between rumination and executive function predicted autobiographical memory specificity over time. Whereas rumination in the context of low executive function predicted reduced specificity, this was not the case in the context of high executive function. The interaction between rumination and executive function was independent of the effects of age, gender, IQ, baseline levels of memory specificity, and depressive symptoms.

Examining overgeneral autobiographical memory as a risk factor for adolescent depression

OBJECTIVE

Identifying risk factors for adolescent depression is an important research aim. Overgeneral autobiographical memory (OGM) is a feature of adolescent depression and a candidate cognitive risk factor for future depression. However, no study has ascertained whether OGM predicts the onset of adolescent depressive disorder. OGM was investigated as a predictor of depressive disorder and symptoms in a longitudinal study of high-risk adolescents. In addition, cross-sectional associations between OGM and current depression and OGM differences between depressed adolescents with different clinical outcomes were examined over time.

METHOD

A 1-year longitudinal study of adolescents at familial risk for depression (n = 277, 10-18 years old) was conducted. Autobiographical memory was assessed at baseline. Clinical interviews assessed diagnostic status at baseline and follow-up.

RESULTS

Currently depressed adolescents showed an OGM bias compared with adolescents with no disorder and those with anxiety or externalizing disorders. OGM to negative cues predicted the onset of depressive disorder and depressive symptoms at follow-up in adolescents free from depressive disorder at baseline. This effect was independent of the contribution of age, IQ, and baseline depressive symptoms. OGM did not predict onset of anxiety or externalizing disorders. Adolescents with depressive disorder at both assessments were not more overgeneral than adolescents who recovered from depressive disorder over the follow-up period.

CONCLUSIONS

OGM to negative cues predicted the onset of depressive disorder (but not other disorders) and depressive symptoms over time in adolescents at familial risk for depression. Results are consistent with OGM as a risk factor for depression.

Twins Born Following Fertility Treatment: Implications for Quantitative Genetic Studies

The rate of multiple births is substantially elevated in women who have had assisted reproduction treatment (ART; ˜26%) compared to the general population (˜1%), and these offspring are usually included in twin studies. Several studies have attempted to identify possible consequences of undergoing ART on the subsequent offspring. However, most studies have only included singleton births. We first examined whether twins born by ART differed from other twins on measures of childhood psychopathology, putative risk factors and correlates, and secondly tested for differences in the degree of twin similarity for available outcome measures. From a population-based twin sample, 101 families with dizygotic (DZ) twins conceived via ART were identified and compared with 1073 naturally conceived (NC) control DZ twin pairs. Analyses performed were (1) univariate and multivariate comparisons of between-group mean differences; and (2) comparison of twin 1–twin 2 correlations between the groups. The groups differed significantly on demographic factors (parental age, family size and social class) and pregnancy variables (smoking during pregnancy and birthweight) but did not differ on family conflict scores or in the frequency of obstetric complications. Family cohesion was higher in the ART group but this was accounted for by demographic factors. For child psychopathology there was a difference between the groups only for teacher-rated ADHD (Attention Deficit Hyperactivity Disorder). Differences were also found between groups for twin correlations. The differences found between ART and NC twins on group means and twin correlations suggest that researchers should be aware that including ART twins may influence results from twin studies.

Offspring of parents with recurrent depression: which features of parent depression index risk for offspring psychopathology?

BACKGROUND

Parental depression is associated with an increased risk of psychiatric disorder in offspring, although outcomes vary. At present relatively little is known about how differences in episode timing, severity, and course of recurrent depression relate to risk in children. The aim of this study was to consider the offspring of parents with recurrent depression and examine whether a recent episode of parental depression indexes risk for offspring psychopathology over and above these other parental depression features.

METHODS

Three hundred and thirty seven recurrently depressed parents and their offspring (aged 9-17) were interviewed as part of an ongoing study, the 'Early Prediction of Adolescent Depression Study'. The Child and Adolescent Psychiatric Assessment was used to assess two child outcomes; presence of a DSM-IV psychiatric disorder and number of DSM-IV child-rated depression symptoms.

RESULTS

Children whose parents had experienced a recent episode of depression reported significantly more depression symptoms, and odds of child psychiatric disorder were doubled relative to children whose parents had not experienced a recent episode of depression. Past severity of parental depression was also significantly associated with child depression symptoms.

LIMITATIONS

Statistical analyses preclude causal conclusions pertaining to parental depression influences on offspring psychopathology; several features of parental depression were recalled retrospectively.

CONCLUSIONS

This study suggests that particular features of parental depression, specifically past depression severity and presence of a recent episode, may be important indicators of risk for child psychiatric disorder and depressive symptoms.

Familial transmission of depression and antisocial behavior symptoms: disentangling the contribution of inherited and environmental factors and testing the mediating role of parenting

BACKGROUND

Genetic and environmental influences on child psychopathology have been studied extensively through twin and adoption designs. We offer a novel methodology to examine genetic and environmental influences on the intergenerational transmission of psychopathology using a sample of parents and children conceived through in vitro fertilization (IVF).

METHOD

The sample included families with children born through IVF methods, who varied as to whether the child was genetically related or unrelated to the rearing mother and father (mother genetically related, n=434; mother genetically unrelated, n=127; father genetically related, n=403; father genetically unrelated, n=156). Using standardized questionnaires, mothers and fathers respectively reported on their own psychopathology (depression, aggression), their parenting behavior toward their child (warmth, hostility) and their child's psychopathology (depression, aggression). A cross-rater approach was used, where opposite parents reported on child symptoms (i.e. fathers reported on symptoms for the mother-child dyad, and vice versa).

RESULTS

For mother-child dyads, a direct association between mother depression and child depression was observed among genetically unrelated dyads, whereas a fully mediated path was observed among genetically related dyads through mother-to-child hostility and warmth. For father-child dyads, direct and mediated pathways were observed for genetically related father-child dyads. For aggression, the direct association between parent aggression and child aggression was fully mediated by parent-to-child hostility for both groups, indicating the role of parent-to-child hostility as a risk mechanism for transmission.

CONCLUSIONS

A differential pattern of genetic and environmental mediation underlying the intergenerational transmission of psychopathology was observed among genetically related and genetically unrelated father-child and mother-child dyads.

Investigating environmental links between parent depression and child depressive/anxiety symptoms using an assisted conception design

OBJECTIVE

Links between maternal and offspring depression symptoms could arise from inherited factors, direct environmental exposure, or shared adversity. A novel genetically sensitive design was used to test the extent of environmental links between maternal depression symptoms and child depression/anxiety symptoms, accounting for inherited effects, shared adversity, and child age and gender.

METHOD

Eight hundred fifty-two families with a child born by assisted conception provided questionnaire data. Mothers and fathers were genetically related or unrelated to the child depending on conception method. Parental depression symptoms were assessed using the Hospital Anxiety and Depression Scale. Child depression/anxiety symptoms were assessed using the Short Mood and Feelings questionnaire and six items tapping generalized anxiety disorder symptoms. Associations between maternal and child symptoms were examined separately for genetically unrelated and related mother-child pairs, adjusting for three measurements of shared adversity: negative life events, family income, and socioeconomic status. Analyses were then run separately for boys and girls and for children and adolescents, and the role of paternal depression symptoms was also examined.

RESULTS

Significant associations between parent and child symptoms were found for genetically unrelated mother-child (r = 0.32, p < .001) and father-child (r = 0.17, p < .05) pairs and genetically related mother-child (r = 0.31, p < .001) and father-child (r = 0.23, p < .001) pairs and were not explained by the shared adversity measurements. Environmental links were present for children and adolescents and were stronger for girls.

CONCLUSIONS

The transmission of depression symptoms is due in part to environmental processes independent of inherited effects and is not accounted for by shared adversity measurements. Girls may be more sensitive to the negative effects of maternal depression symptoms than boys through environmental processes.

Can basic risk research help in the prevention of childhood and adolescent depression? Examining a cognitive and emotional regulation approach

This paper aims to highlight ways in which basic research findings in the field of childhood and adolescent depression can help to inform and refine preventive intervention efforts. We selectively review basic research evidence from community, clinical, and high-risk populations that identifies cognitive mechanisms (thought processes and reactions to negative affect) and emotional regulation as key processes involved in the onset and maintenance of depression. We focus on cognitive and emotional mechanisms in order to allow comparability with the majority of current preventive interventions. A range of basic research strategies and studies are then suggested that could be employed to help the development and refinement of prevention strategies. These include the need for prospective longitudinal studies to identify causal risk and protective factors, an integration of research approaches and methods, and a focus on understanding potential aetiological heterogeneity between childhood and adolescent depression.

Genetics of childhood and adolescent depression: insights into etiological heterogeneity and challenges for future genomic research

There is heterogeneity between depression in childhood, adolescence and adulthood in terms of the gender composition of affected cases, prevalence, rates of recurrence and risk factors. This raises complex questions for refining the phenotype for molecular genetic studies of depression and the selection of appropriate proband groups. This article aims to provide a review of issues arising from family, twin and adoption studies of relevance to molecular genetic studies, and to summarize molecular genetic findings on childhood/adolescent depression. While retrospective studies of adults suggest greater familial aggregation among those with an earlier age of onset, prospective studies do not confirm this association. In fact, taken together, evidence from family and twin studies suggests that prepubertal depression is more strongly associated with psychosocial adversity, is less heritable and shows lower levels of continuity with adult depression than either adolescent or adult depression. Adolescent depressive symptoms and disorder show similar levels of heritability to depression in adult life, although there is only one twin study of adolescent depressive disorder, and heritability estimates of depressive symptoms vary widely between studies. This variability in heritability estimates is partly attributable to age and informant effects. Adoption studies and other intergenerational transmission designs show that the transmission of depression between parents and children involves genetic and environmental processes, with converging evidence that environmental processes are most important. Molecular genetic studies of childhood/adolescent depression have to date used a candidate gene approach and focused on genes already examined in adult studies. Prospective longitudinal studies of community and high-risk samples are needed to clarify issues of etiological heterogeneity in depression, and these should in turn inform the planning of molecular genetic studies.

Estimating the relative contributions of maternal genetic, paternal genetic and intrauterine factors to offspring birth weight and head circumference

BACKGROUND

Genetic factors and the prenatal environment contribute to birth weight. However, very few types of study design can disentangle their relative contribution.

AIMS

To examine maternal genetic and intrauterine contributions to offspring birth weight and head circumference. To compare the contribution of maternal and paternal genetic effects.

STUDY DESIGN

Mothers and fathers were either genetically related or unrelated to their offspring who had been conceived by in vitro fertilization.

SUBJECTS

423 singleton full term offspring, of whom 262 were conceived via homologous IVF (both parents related), 66 via sperm donation (mother only related) and 95 via egg donation (father only related).

MEASURES

Maternal weight at antenatal booking, current weight and maternal height. Paternal current weight and height were all predictors. Infant birth weight and head circumference were outcomes.

RESULTS

Genetic relatedness was the main contributing factor between measures of parental weight and offspring birth weight as correlations were only significant when the parent was related to the child. However, there was a contribution of the intrauterine environment to the association between maternal height and both infant birth weight and infant head circumference as these were significant even when mothers were unrelated to their child.

CONCLUSIONS

Both maternal and paternal genes made contributions to infant birth weight. Maternal height appeared to index a contribution of the intrauterine environment to infant growth and gestational age. Results suggested a possible biological interaction between the intrauterine environment and maternal inherited characteristics which suppresses the influence of paternal genes.

The links between prenatal stress and offspring development and psychopathology: disentangling environmental and inherited influences

BACKGROUND

Exposure to prenatal stress is associated with later adverse health and adjustment outcomes. This is generally presumed to arise through early environmentally mediated programming effects on the foetus. However, associations could arise through factors that influence mothers' characteristics and behaviour during pregnancy which are inherited by offspring.

METHOD

A 'prenatal cross-fostering' design where pregnant mothers are related or unrelated to their child as a result of in vitro fertilization (IVF) was used to disentangle maternally inherited and environmental influences. If links between prenatal stress and offspring outcome are environmental, association should be observed in unrelated as well as related mother-child pairs. Offspring birth weight and gestational age as well as mental health were the outcomes assessed.

RESULTS

Associations between prenatal stress and offspring birth weight, gestational age and antisocial behaviour were seen in both related and unrelated mother-offspring pairs, consistent with there being environmental links. The association between prenatal stress and offspring anxiety in related and unrelated groups appeared to be due to current maternal anxiety/depression rather than prenatal stress. In contrast, the link between prenatal stress and offspring attention deficit hyperactivity disorder was only present in related mother-offspring pairs and therefore was attributable to inherited factors.

CONCLUSIONS

Genetically informative designs can be helpful in testing whether inherited factors contribute to the association between environmental risk factors and health outcomes. These results suggest that associations between prenatal stress and offspring outcomes could arise from inherited factors and post-natal environmental factors in addition to causal prenatal risk effects.

Prenatal smoking might not cause attention-deficit/hyperactivity disorder: evidence from a novel design

BACKGROUND

It is widely considered that exposure to maternal cigarette smoking in pregnancy has risk effects on offspring attention-deficit/hyperactivity disorder (ADHD). This view is supported by consistent observations of association. It is, however, impossible to be certain of adequate control for confounding factors with observational designs. We use a novel "natural experiment" design that separates prenatal environmental from alternative inherited effects.

METHODS

The design is based on offspring conceived with Assisted Reproductive Technologies recruited from 20 fertility clinics in the United Kingdom and United States who were: 1) genetically unrelated, and 2) related to the woman who underwent the pregnancy. If maternal smoking in pregnancy has true risk effects, association will be observed with ADHD regardless of whether mother and offspring are related or unrelated. Data were obtained from 815 families of children ages 4 years-11 years with parent questionnaires and antenatal records. Birth weight was used as a comparison outcome. The key outcome considered was child ADHD symptoms.

RESULTS

Association between smoking in pregnancy and lower birth weight was found in unrelated and related mother-offspring pairs, consistent with a true risk effect. However, for ADHD symptoms, the magnitude of association was significantly higher in the related pairs (beta = .102, p < .02) than in the unrelated pairs (beta= -.052, p > .10), suggesting inherited effects.

CONCLUSIONS

Our findings highlight the need to test causal hypotheses with genetically sensitive designs. Inherited confounds are not necessarily removed by statistical controls. The previously observed association between maternal smoking in pregnancy and ADHD might represent an inherited effect.

Associations between maternal older age, family environment and parent and child wellbeing in families using assisted reproductive techniques to conceive

Maternal age effects on parenting and family outcomes are of increasing interest because of the demographic shift toward older maternal age at first birth. Maternal age is also of interest because of the greater use of assisted reproductive techniques (ART) to bypass age-related infertility in couples trying to conceive late in the reproductive life cycle of the woman. The aim of the present study was to investigate maternal age effects associated with delayed parenting by comparing families of mothers who gave birth at a younger (<31 years) or older (>38 years) age and to ascertain whether associations were linear associations by comparing these groups to women who had conceived in between these ages (i.e., >31 and <38 years). All children (4-11 year olds) were first-born and conceived using ART. Participants were recruited from one of 20 fertility clinics and mothers (n=642) and fathers (n=439) completed a postal questionnaire about demographic and reproductive characteristics, family environment as well as parent and child wellbeing. Our results demonstrate that parenthood via assisted conception later in the reproductive life cycle is not associated with a negative impact on child wellbeing. Despite maternal age-group differences on demographic (education, income) and reproductive characteristics (bleeding during pregnancy, caesarean rate, breast feeding), and parental warmth and depressive symptoms, child wellbeing was similar across mother age groups. We conclude that the parenting context is different for older mother families (more depressive symptoms in mothers and fathers, less expressed warmth in the couple) but that this difference is not associated with child wellbeing in early and middle childhood.

The genetics of depression in childhood and adolescence

This article reviews family, twin, and adoption studies of childhood and adolescent depression. Results from several family and twin studies suggest that an etiologic heterogeneity exists in depression in childhood and adolescence. Twin studies show that genetic influences on depression in young people may be indirect and work via effects on environmental risk exposure (gene-environment correlation) or genetic sensitivity to environmental risks (gene-environment interaction). Recent research on gene-environment interaction has examined the effect of specific functional genetic polymorphisms in conjunction with environmental stressors. Future research needs to work toward identifying which environmental and genetic risk factors are crucial to the development of depression in youth, as well as mechanisms involved in the familial transmission of depression. This will not only improve understanding of the etiology of childhood and adolescent depression but also inform the development of therapeutic and preventive interventions.

Psychopathy traits in adolescents with childhood attention-deficit hyperactivity disorder

BACKGROUND

Children with attention-deficit hyperactivity disorder (ADHD) are thought to be at higher risk of psychopathy. Early biological and social adversity may contribute to this risk.

AIMS

To examine psychopathy traits in ADHD.

METHOD

In a sample of children with ADHD who had reached adolescence, total psychopathy and 'emotional-dysfunction' scores (e.g. callousness, lack of affect) were assessed using the Hare Psychopathy Checklist-Youth Version.

RESULTS

A total of 156 (79%) eligible families participated. Total psychopathy and emotional-dysfunction scores were elevated in comparison to published UK norms but none scored in the clinical range for psychopathy. Adjusting for associated conduct problems, total psychopathy scores were associated with maternal smoking during pregnancy, emotional-dysfunction scores were associated with birth complications, and neither was associated with family adversity.

CONCLUSIONS

Children with ADHD show psychopathy traits but are not 'psychopaths'. Early adversity, indexed by pre- or perinatal adversity but not family factors, appears to be associated.

Testing for gene x environment interaction effects in attention deficit hyperactivity disorder and associated antisocial behavior

Gene x environment (G x E) interactions are increasingly thought to have substantial influence on the aetiology and clinical manifestations of complex disorders. In ADHD, although main effects of specific genetic variants and pre- or peri-natal variables have been reported and replicated using pooled analyses, few studies have looked at possible interactions. In a clinical sample of 266 children with ADHD, we tested for interaction between gene variants (in DRD4, DAT1, DRD5, and 5HTT) found to be associated with ADHD in pooled analyses and maternal smoking, alcohol use during pregnancy and birth weight. First, G x E effects on a diagnosis of ADHD were tested using conditional logistic regression analyses. Second, possible modifying effects of G x E on symptoms of associated conduct disorder and oppositional defiant disorder (ODD) were investigated using linear regression analysis. The sample size associated with each of the analyses differed as not each variant had been genotyped for each individual. No effects of G x E on ADHD diagnosis were observed. The results suggest that lower birth weight and maternal smoking during pregnancy may interact with DRD5 and DAT1 (birth weight only) in influencing associated antisocial behavior symptoms (ODD and conduct disorder). These preliminary findings showed no evidence of interaction between previously implicated variants in ADHD and specific environmental risk factors, on diagnosis of the disorder. There may be evidence of G x E on associated antisocial behavior in ADHD, but further investigation is needed.

The association between conduct problems and the initiation and progression of marijuana use during adolescence: a genetic analysis across time

The present study used a prospective, longitudinal design to investigate genetic and environmental influences on the association between earlier conduct problems and the initiation and progression of marijuana use during adolescence. Parent- and teacher-reported conduct problems assessed at Time 1 (1996) and self-reported marijuana use assessed at Time 2 (2004) were available for 1088 adolescent twin pairs participating in the Cardiff Study of All Wales and North West of England Twins (CaStANET). Using a novel approach to the modeling of initiation and progression dimensions in substance use, findings suggested that the initiation of marijuana use in adolescence was influenced by genetic, common and unique environmental factors. The progression (or frequency) of marijuana use was influenced by genetic and unique environmental factors. Findings for conduct problems indicated that while the presence or absence of conduct problems was largely heritable, the relative severity of conduct problems appeared to be more strongly environmentally influenced. Multivariate model fitting indicated that conduct problems in childhood and early adolescence made a small but significant contribution to the risk for marijuana use 8 years later.

Mental health and functional outcomes of maternal and adolescent reports of adolescent depressive symptoms

OBJECTIVE

To assess the value of maternal and self-ratings of adolescent depression by investigating the extent to which these reports predicted a range of mental health and functional outcomes 4 years later. The potential influence of mother's own depressed mood on her ratings of adolescent depression and suicidal ideation on adolescent outcome was also tested.

METHOD

A longitudinal population-based study of 842 adolescents ages 11 to 16 at the baseline assessment and 15 to 20 at follow-up (62% retention).

RESULTS

Both mother- and adolescent-rated depressive symptoms predicted future depression, antisocial behavior, impairment, health service use, and regular tobacco use in the adolescent. The odds ratios obtained for maternal and adolescent ratings of depressive symptoms as predictors of future psychopathology were not significantly different. Mothers' own depressive symptoms were not significantly associated with adolescent depression, health service use, or substance use at follow-up. Depression that was accompanied by adolescent-rated suicidal thoughts was significantly more strongly associated with impairment at follow-up than depression alone.

CONCLUSIONS

It is possible to obtain clinically useful information on adolescent depression from the child's mother. However, information on suicidal ideation was rarely endorsed by mothers, suggesting that maternal report of adolescent suicidal thoughts shows less sensitivity than adolescent report.

Clinical supervision for mental health nurses in Northern Ireland: formulating best practice guidelines

Nurses work in a constantly challenging and changing environment. Within this context, there is a continuing need for support. Such support will help increase morale, decrease strain and burnout, and encourage self-awareness and self-expression. Clinical supervision address all these issues and enhances the quality of care for patients. While clinical supervision is a policy imperative in Northern Ireland, it was clear that there were problems in its implementation in mental health nursing. The aim of this project was to explore ways to make clinical supervision available to all mental health nurses and to improve and evaluate their contribution to patient care. The research team undertook a comprehensive literature review and a baseline survey of relevant stakeholders. Results represent the outcome of the group work. They will assist healthcare providers to develop local policies and procedures on clinical supervision for practising mental health nurses.

Agreement between maternal report and antenatal records for a range of pre and peri-natal factors: the influence of maternal and child characteristics

BACKGROUND

Events during pregnancy and labour may influence the future health and well-being of offspring. Many studies rely on maternal reports of pre and peri-natal factors. Both maternal and child characteristics may potentially influence the reliability and accuracy of maternal recall. However, this has not been previously examined.

AIMS

To examine agreement between information from maternally reported questionnaires and medical records for a range of pre and peri-natal factors. To examine whether maternal and child characteristics influence the level of agreement with medical records.

METHODS

A survey of women who had school aged children born following in vitro fertilization (IVF) was carried out. Mothers completed a postal questionnaire booklet which included the Lewis and Murray scale which asks about antenatal and obstetric complications and the Strengths and Difficulties Questionnaire which assesses child behaviour problems. Antenatal case notes were also reviewed. Multi-centre ethical approval was obtained. Complete data were available for 126 women.

RESULTS

The agreement between maternal report and medical records was very good for the majority of outcomes examined (infant birth weight, infant admission to special care baby unit, method of delivery, smoking during pregnancy, high blood pressure/oedema during pregnancy). Exceptions were length of labour and alcohol use during pregnancy. However, alcohol use during pregnancy was not routinely recorded in medical records. Maternal characteristics did not substantially influence level of agreement for the majority of outcomes examined. Exceptions were that agreement for length of labour was better in women with more educational qualifications and that agreement for pre-natal smoking was worse in women from higher socio-occupational groups. There was little evidence that child behaviour problems influenced the level of agreement between maternal recall and medical records.

CONCLUSIONS

For the majority of pre and peri-natal events examined, mothers can provide accurate reports in comparison to information from medical records.

The Cardiff Study of all Wales and North West of England Twins (CaStANET): a longitudinal research program of child and adolescent development

The study of twins and their families provides a highly useful tool for disentangling the genetic and environmental origins of traits. The Cardiff Study of All Wales and North West of England Twins (CaStANET) has followed children and adolescents over time into early adulthood, assessing a wide range of aspects of behavior and psychopathology using self-, parent and teacher reports. Four main waves of data collection have taken place to date, which have provided a wealth of information on the contributions of genetic and environmental risk factors to the psychological health of young people. This article first describes the CaStANET register and subsequently presents some of the findings that have emerged from this resource, with a focus on depression and anxiety, chronic fatigue, attention-deficit/hyperactivity disorder, conduct problems and prosocial behavior. We describe in somewhat more detail the 4th wave of data collection, which has recently been completed and has provided us with extensive information on substance use and problem use as well as associated risk factors in the twins and their families, including longitudinal data on conduct problems and the relations between family members. Because of the wealth of data already collected and the opportunity for genetically informative analyses over time, CaStANET provides a valuable resource for understanding the complexities of the psychological development of young people.

Do intrauterine or genetic influences explain the foetal origins of chronic disease? A novel experimental method for disentangling effects

BACKGROUND

There is much evidence to suggest that risk for common clinical disorders begins in foetal life. Exposure to environmental risk factors however is often not random. Many commonly used indices of prenatal adversity (e.g. maternal gestational stress, gestational diabetes, smoking in pregnancy) are influenced by maternal genes and genetically influenced maternal behaviour. As mother provides the baby with both genes and prenatal environment, associations between prenatal risk factors and offspring disease maybe attributable to true prenatal risk effects or to the "confounding" effects of genetic liability that are shared by mother and offspring. Cross-fostering designs, including those that involve embryo transfer have proved useful in animal studies. However disentangling these effects in humans poses significant problems for traditional genetic epidemiological research designs.

METHODS

We present a novel research strategy aimed at disentangling maternally provided pre-natal environmental and inherited genetic effects. Families of children aged 5 to 9 years born by assisted reproductive technologies, specifically homologous IVF, sperm donation, egg donation, embryo donation and gestational surrogacy were contacted through fertility clinics and mailed a package of questionnaires on health and mental health related risk factors and outcomes. Further data were obtained from antenatal records.

RESULTS

To date 741 families from 18 fertility clinics have participated. The degree of association between maternally provided prenatal risk factor and child outcome in the group of families where the woman undergoing pregnancy and offspring are genetically related (homologous IVF, sperm donation) is compared to association in the group where offspring are genetically unrelated to the woman who undergoes the pregnancy (egg donation, embryo donation, surrogacy). These comparisons can be then examined to infer the extent to which prenatal effects are genetically and environmentally mediated.

CONCLUSION

A study based on children born by IVF treatment and who differ in genetic relatedness to the woman undergoing the pregnancy is feasible. The present report outlines a novel experimental method that permits disaggregation of maternally provided inherited genetic and post-implantation prenatal effects.

Genetic and environmental influences on the relationship between peer alcohol use and own alcohol use in adolescents

AIMS

Genetically influenced aspects of adolescent behaviour can play a role in alcohol use and peer affiliation. We explored the correlations between friends' alcohol use and adolescent own use with a genetically sensitive design.

DESIGN

Genetic and environmental factors were estimated on adolescent reports of their friends' alcohol use and their own use and problem use of alcohol. The correlations between the genetic and environmental factors that influence friends' alcohol use and adolescent own alcohol use and problem use were also estimated.

PARTICIPANTS

A total of 862 twin pairs aged 11-17 years sampled from the UK population-based Cardiff Study of All Wales and North-west of England Twins (CaStANET).

MEASUREMENTS

Data on adolescent own alcohol use and problem use and the alcohol use of their three best friends were obtained using self-report questionnaires.

FINDINGS

A significant genetic influence was found on adolescent friends' alcohol use (about 30%). Significant correlations of 0.60 and 0.70 were found between the genetic influences on friends' alcohol use and adolescents' own use and problem use of alcohol. Common environmental influences were almost completely correlated for friends' alcohol use and adolescents' own alcohol use and problem use (0.91 and 0.94).

CONCLUSIONS

There is considerable overlap in the common environmental and genetic factors that contribute to the relationship between adolescents' own alcohol use and that of their friends. These findings contribute to understanding of the mechanisms by which friends' alcohol use influences adolescent drinking behaviour.

The impact of gestational stress and prenatal growth on emotional problems in offspring: a review

OBJECTIVE

Events occurring very early in life, even prenatally, may have long-term effects on future health and behaviour. The influence of poor foetal growth and gestational stress in the mother on the risk of emotional problems in offspring was reviewed.

METHOD

A selective review of the literature was undertaken.

RESULTS

Studies of preterm infants and infants born small for gestational age have shown increased levels of emotional problems across the lifespan. In general, studies examining maternal depression/anxiety during pregnancy and other indices of gestational stress have shown significant associations with emotional problems in children. The results of several studies also point to the importance of psychosocial and genetic factors in moderating associations.

CONCLUSION

Future research that focuses on identifying the mechanisms underlying these associations is needed. The moderating role of psychosocial and genetic risk factors is an important area in which future research should be directed. These findings have clinical implications for the provision of antenatal care.

Exploring the relationship between genetic and environmental influences on initiation and progression of substance use

AIMS

To examine the genetic and environmental contributions to the initiation of use and progression to more serious use of alcohol, cigarettes and marijuana during adolescence, and to examine the relationship between initiation and progression of substance use.

DESIGN

The study used a twin-based design and a new theoretical model, the causal-common-contingent (CCC) model. This allows modelling of the relationship between initiation of use and progression to heavier use as a two-stage model and the examination of genetic and environmental influences on both stages, while taking into account their relationship.

PARTICIPANTS

The participants consisted of 1214 twin pairs (69% response rate) aged 11-19 years sampled from the UK population-based Cardiff Study of All Wales and North-west of England Twins (CaStANET).

MEASUREMENTS

Data on adolescent initiation and progression to more serious use of alcohol, cigarettes and marijuana were obtained using self-report questionnaires.

FINDINGS

Initiation of alcohol and progression to heavier alcohol use had separate but related underlying aetiologies. For cigarette and marijuana use the relation between initiation and progression to heavier use was stronger, suggesting greater overlap in aetiologies. For all three substances, environmental influences that make twins more similar (common environment) tended to be greater for initiation, while genetic influences were stronger for heavier use.

CONCLUSIONS

These findings have implications for policy decisions aimed at an adolescent and early adult age group. Specifically, these findings suggest that it may be more efficacious to focus alcohol interventions on risk factors for the development of heavier use rather than initiation of use. In contrast, interventions aimed at reducing the initiation of cigarettes and marijuana use may be more appropriate.

Twin studies in pediatric depression

Pediatric depression is an important clinical problem that is known to be familial. Twin studies have been used not only to examine the genetic etiology of depression but also to investigate developmental changes and gender effects, the relationship of depression with anxiety, and increasingly, the interplay of genetic liability with environmental risk factors. There is evidence that pediatric depression symptom scores and clinical depression are genetically influenced, but results from different twin studies have varied. These studies also have demonstrated the important contribution of environmental risk factors. Some of the differences in findings may be caused partly by clinical heterogeneity, developmental differences in etiology (stronger genetic influences for depression symptom scores in adolescence than in childhood), and measurement issues, such as who rates the symptoms.

The effect of birth-weight with genetic susceptibility on depressive symptoms in childhood and adolescence

Low birth-weight has been associated with depression and related outcomes in adults, and with problem behaviours in children. This study aimed to examine the association between low birth-weight for gestation and depressive symptoms in children and adolescents and to examine whether the relationship is moderated by genetic risk for depression. An epidemiological, genetically sensitive design was used including 2,046 twins aged 8-17 years (1,023 families). Data were obtained by parental report and analysed using regression analysis. A small but significant association between birth-weight for gestation and early depressive symptoms was observed. The unit increase in depressive symptoms per unit decrease in birth-weight for gestation was greater for individuals at genetic or familial risk for depression. For low birth-weight children, genetic risk for depression moderated the influence of birth-weight for gestation in predicting early depressive symptoms. Birth-weight for gestation is moderated by genetic and familial risk for depression in influencing early depression symptoms. These observations have clinical implications in that the impact of being small for gestational age on depressive symptoms is greater in children at familial/genetic risk although the association between birth weight and depression does not imply causality.

Relationship between disabling fatigue and depression in children: genetic study

BACKGROUND

Medically unexplained disabling fatigue in young people is familial and frequently associated with depressed mood.

AIMS

To examine the degree of sharing of genetic and environmental influences on the symptoms of depression and fatigue in this age group.

METHOD

The parents of twins aged 8-17 years, derived from a population-based register, completed a questionnaire regarding lifetime-ever disabling fatigue in both twins. Twins aged 11 years or over completed the Mood and Feelings Questionnaire. The genetic and environmental influences on fatigue and the relationship with depression were examined using bivariate genetic analysis.

RESULTS

Parent-rated data were obtained for 1468 twin pairs (65%) and self-rated data from 930 older twin pairs (58%). Bivariate analysis of fatigue and depression suggested that genetic and environmental influences on disabling fatigue were mainly specific to fatigue.

CONCLUSIONS

Unexplained disabling fatigue in childhood is substantially familial and has mainly an independent aetiology from depression.

Family conflict interacts with genetic liability in predicting childhood and adolescent depression

OBJECTIVE

To test for gene-environment interaction with depressive symptoms and family conflict. Specifically, to first examine whether the influence of family conflict in predicting depressive symptoms is increased in individuals at genetic risk of depression. Second, to test whether the genetic component of variance in depressive symptoms increases as levels of family conflict increase.

METHOD

A longitudinal twin design was used. Children ages 5 to 16 were reassessed approximately 3 years later to test whether the influence of family conflict in predicting depressive symptoms varied according to genetic liability. The conflict subscale of the Family Environment Scale was used to assess family conflict and the Mood and Feelings Questionnaire was used to assess depressive symptoms. The response rate to the questionnaire at time 1 was 73% and 65% at time 2. Controlling for initial symptoms levels (i.e., internalizing at time 1), primary analyses were conducted using ordinary least-squares multiple regression. Structural equation models, using raw score maximum likelihood estimation, were also fit to the data for the purpose of model fit comparison.

RESULTS

Results suggested significant gene-environment interaction specifically with depressive symptoms and family conflict. Genetic factors were of greater importance in the etiology of depressive symptoms where levels of family conflict were high. The effects of family conflict on depressive symptoms were greater in children and adolescents at genetic risk of depression.

CONCLUSIONS

The present results suggest that children with a family history of depression may be at an increased risk of developing depressive symptoms in response to family conflict. Intervention programs that incorporate one or more family systems may be of benefit in alleviating the adverse effect of negative family factors on children.