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Attention-deficit hyperactivity disorder (ADHD) is associated with later depression and there is considerable genetic overlap between them. This study investigated if ADHD and ADHD genetic liability are causally related to depression using two different methods.
First, a longitudinal population cohort design was used to assess the association between childhood ADHD (age 7 years) and recurrent depression in young-adulthood (age 18–25 years) in N = 8310 individuals in the Avon Longitudinal Study of Parents and Children (ALSPAC). Second, two-sample Mendelian randomization (MR) analyses examined relationships between genetic liability for ADHD and depression utilising published Genome-Wide Association Study (GWAS) data.
Childhood ADHD was associated with an increased risk of recurrent depression in young-adulthood (OR 1.35, 95% CI 1.05–1.73). MR analyses suggested a causal effect of ADHD genetic liability on major depression (OR 1.21, 95% CI 1.12–1.31). MR findings using a broader definition of depression differed, showing a weak influence on depression (OR 1.07, 95% CI 1.02–1.13).
Our findings suggest that ADHD increases the risk of depression later in life and are consistent with a causal effect of ADHD genetic liability on subsequent major depression. However, findings were different for more broadly defined depression.
There is an enormous interest in identifying the causes of psychiatric disorders but there are considerable challenges in identifying which risks are genuinely causal. Traditionally risk factors have been inferred from observational designs. However, association with psychiatric outcome does not equate to causation. There are a number of threats that clinicians and researchers face in making causal inferences from traditional observational designs because adversities or exposures are not randomly allocated to individuals. Natural experiments provide an alternative strategy to randomized controlled trials as they take advantage of situations whereby links between exposure and other variables are separated by naturally occurring events or situations. In this review, we describe a growing range of different types of natural experiment and highlight that there is a greater confidence about findings where there is a convergence of findings across different designs. For example, exposure to hostile parenting is consistently found to be associated with conduct problems using different natural experiment designs providing support for this being a causal risk factor. Different genetically informative designs have repeatedly found that exposure to negative life events and being bullied are linked to later depression. However, for exposure to prenatal cigarette smoking, while findings from natural experiment designs are consistent with a causal effect on offspring lower birth weight, they do not support the hypothesis that intra-uterine cigarette smoking has a causal effect on attention-deficit/hyperactivity disorder and conduct problems and emerging findings highlight caution about inferring causal effects on bipolar disorder and schizophrenia.
Identifying prenatal environmental factors that have genuinely causal effects on psychopathology is an important research priority, but it is crucial to select an appropriate research design. In this review we explain why and what sorts of designs are preferable and focus on genetically informed/sensitive designs. In the field of developmental psychopathology, causal inferences about prenatal risks have not always been based on evidence generated from appropriate designs. We focus on reported links between maternal smoking during pregnancy and offspring attention-deficit/hyperactivity disorder or conduct problems. Undertaking a systematic review of findings from genetically informed designs and “triangulating” evidence from studies with different patterns of bias, we conclude that at present findings suggest it is unlikely that there is a substantial causal effect of maternal smoking in pregnancy on either attention-deficit/hyperactivity disorder or conduct problems. In contrast, for offspring birth weight (which serves as a positive control) findings strongly support a negative causal effect of maternal smoking in pregnancy. For maternal pregnancy stress, too few studies use genetically sensitive designs to draw firm conclusions, but continuity with postnatal stress seems important. We highlight the importance of moving beyond observational designs, for systematic evaluation of the breadth of available evidence and choosing innovative designs. We conclude that a broader set of prenatal risk factors should be examined, including those relevant in low- and middle-income contexts. Future directions include a greater use of molecular genetically informed designs such as Mendelian randomization to test causal hypotheses about prenatal exposure and offspring outcome.
Previous studies find that both schizophrenia and mood disorder risk alleles contribute to adult depression and anxiety. Emotional problems (depression or anxiety) begin in childhood and show strong continuities into adult life; this suggests that symptoms are the manifestation of the same underlying liability across different ages. However, other findings suggest that there are developmental differences in the etiology of emotional problems at different ages. To our knowledge, no study has prospectively examined the impact of psychiatric risk alleles on emotional problems at different ages in the same individuals.
Data were analyzed using regression-based analyses in a prospective, population-based UK cohort (the National Child Development Study). Schizophrenia and major depressive disorder (MDD) polygenic risk scores (PRS) were derived from published Psychiatric Genomics Consortium genome-wide association studies. Emotional problems were assessed prospectively at six time points from age 7 to 42 years.
Schizophrenia PRS were associated with emotional problems from childhood [age 7, OR 1.09 (1.03–1.15), p = 0.003] to mid-life [age 42, OR 1.10 (1.05–1.17), p < 0.001], while MDD PRS were associated with emotional problems only in adulthood [age 42, OR 1.06 (1.00–1.11), p = 0.034; age 7, OR 1.03 (0.98–1.09), p = 0.228].
Our prospective investigation suggests that early (childhood) emotional problems in the general population share genetic risk with schizophrenia, while later (adult) emotional problems also share genetic risk with MDD. The results suggest that the genetic architecture of depression/anxiety is not static across development.
Objectives: Previous studies have found that oxytocin (OXT) can improve the recognition of emotional facial expressions; it has been proposed that this effect is mediated by an increase in attention to the eye-region of faces. Nevertheless, evidence in support of this claim is inconsistent, and few studies have directly tested the effect of oxytocin on emotion recognition via altered eye-gaze Methods: In a double-blind, within-subjects, randomized control experiment, 40 healthy male participants received 24 IU intranasal OXT and placebo in two identical experimental sessions separated by a 2-week interval. Visual attention to the eye-region was assessed on both occasions while participants completed a static facial emotion recognition task using medium intensity facial expressions. Results: Although OXT had no effect on emotion recognition accuracy, recognition performance was improved because face processing was faster across emotions under the influence of OXT. This effect was marginally significant (p<.06). Consistent with a previous study using dynamic stimuli, OXT had no effect on eye-gaze patterns when viewing static emotional faces and this was not related to recognition accuracy or face processing time. Conclusions: These findings suggest that OXT-induced enhanced facial emotion recognition is not necessarily mediated by an increase in attention to the eye-region of faces, as previously assumed. We discuss several methodological issues which may explain discrepant findings and suggest the effect of OXT on visual attention may differ depending on task requirements. (JINS, 2017, 23, 23–33)
Past research has identified maternal depression and family of origin maltreatment as precursors to adolescent depression and antisocial behavior. Caregiving experiences have been identified as a factor that may ameliorate or accentuate adolescent psychopathology trajectories. Using a multilevel approach that pools the unique attributes of two geographically diverse, yet complementary, longitudinal research designs, the present study examined the role of maternal caregiver involvement as a factor that promotes resilience-based trajectories related to depressive symptoms and antisocial behaviors among adolescent girls. The first sample comprises a group of US-based adolescent girls in foster care (n = 100; mean age = 11.50 years), each of whom had a history of childhood maltreatment and removal from their biological parent(s). The second sample comprises a group of UK-based adolescent girls at high familial risk for depression (n = 145; mean age = 11.70 years), with all girls having biological mothers who experienced recurrent depression. Analyses examined the role of maternal caregiving on girls' trajectories of depression and antisocial behavior, while controlling for levels of co-occurring psychopathology at each time point. Results suggest increasing levels of depressive symptoms for girls at familial risk for depression but decreasing levels of depression for girls in foster care. Foster girls' antisocial behavior also decreased over time. Maternal caregiver involvement was differentially related to intercept and slope parameters in both samples. Results are discussed with respect to the benefits of applying multilevel (multisample, multiple outcome) approaches to identifying family-level factors that can reduce negative developmental outcomes in high-risk youth.
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.
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.
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.
Children with 22q11.2 deletion syndrome (22q11.2DS) have been reported to have high rates of cognitive and psychiatric problems.
To establish the nature and prevalence of psychiatric disorder and neurocognitive impairment in children with 22q11.2DS and test whether risk of psychopathology is mediated by the children's intellectual impairment.
Neurocognition and psychopathology were assessed in 80 children with 22q11.2DS (mean age 10.2 years, s.d. = 2.1) and 39 sibling controls (mean age 10.9 years, s.d. = 2.0).
More than half (54%) of children with 22q11.2DS met diagnostic criteria for one or more DSM-IV-TR psychiatric disorder. These children had lower IQ (mean 76.8, s.d. = 13.0) than controls (mean 108.6, s.d. = 15.2) (P<0.001) and showed a range of neurocognitive impairments. Increased risk of psychopathology was not mediated by intellectual impairment.
22q11.2DS is not related to a specific psychiatric phenotype in children. Moreover, the deletion has largely independent effects on IQ and risk of psychopathology, indicating that psychopathology in 22q11.2DS is not a non-specific consequence of generalised cognitive impairment.
There is recent evidence of some degree of shared genetic susceptibility between adult schizophrenia and childhood attention-deficit hyperactivity disorder (ADHD) for rare chromosomal variants.
To determine whether there is overlap between common alleles conferring risk of schizophrenia in adults with those that do so for ADHD in children.
We used recently published Psychiatric Genome-wide Association Study (GWAS) Consortium (PGC) adult schizophrenia data to define alleles over-represented in people with schizophrenia and tested whether those alleles were more common in 727 children with ADHD than in 2067 controls.
Schizophrenia risk alleles discriminated ADHD cases from controls (P = 1.04 × 104, R2 = 0.45%); stronger discrimination was given by alleles that were risk alleles for both adult schizophrenia and adult bipolar disorder (also derived from a PGC data-set) (P = 9.98 ×10−6, R2 × 0.59%).
This increasing evidence for a small, but significant, shared genetic susceptibility between adult schizophrenia and childhood ADHD highlights the importance of research work across traditional diagnostic boundaries.
Parental depression is associated with disruptions in the parent–child relationship, exposure to stressful family life events, and offspring depressive symptoms. Evidence suggests that intergenerational transmission of depression involves environmental and inherited contributions. We sought to evaluate the role of passive gene–environment correlation (rGE) in relation to depression, family life events that were due to parental behavior, and parental positivity in a sample where children varied in genetic relatedness to their rearing parents. Our study included 865 families with children born through assisted conception (444 related to both parents, 210 related to the mother only, 175 related to the father only, and 36 related to neither parent). Consistent with previous studies, the intergenerational transmission of depressive symptoms was largely due to environmental factors, although parent and child gender influenced results. Maternal and paternal depressive symptoms were associated with reduced positivity and increased parentally imposed life events regardless of parent–child relatedness. Results of path analysis were consistent with passive rGE for both maternal and paternal positivity in that positivity partially mediated the link between maternal/paternal depression and child depression only in genetically related parent–child pairs. Results also suggested passive rGE involving parentally imposed life events for mothers and fathers although passive rGE effects were smaller than for positivity.
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.
To consider whether the overall burden of co-occurring psychopathology in mothers with recurrent depression predicts new-onset psychopathology in offspring.
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.
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).
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.
Past research has linked interparental conflict, parent psychopathology, hostile parenting, and externalizing behavior problems in childhood. However, few studies have examined these relationships while simultaneously allowing the contribution of common genetic factors underlying associations between family- and parent-level variables on child psychopathology to be controlled. Using the attributes of a genetically sensitive in vitro fertilization research design, the present study examined associations among interparental conflict, parents' antisocial behavior problems, parents' anxiety symptoms, and hostile parenting on children's antisocial behavior problems among genetically related and genetically unrelated mother–child and father–child groupings. Path analyses revealed that for genetically related mothers, interparental conflict and maternal antisocial behavior indirectly influenced child antisocial behavior through mother-to-child hostility. For genetically unrelated mothers, effects were apparent only for maternal antisocial behavior on child antisocial behavior through mother-to-child hostility. For both genetically related and genetically unrelated fathers and children, interparental conflict and paternal antisocial behavior influenced child antisocial behavior through father-to-child hostility. Effects of parental anxiety symptoms on child antisocial behavior were apparent only for genetically related mothers and children. Results are discussed with respect to the relative role of passive genotype–environment correlation as a possible confounding factor underlying family process influences on childhood psychopathology.
Submicroscopic, rare chromosomal copy number variants (CNVs) contribute to neurodevelopmental disorders but it is not known whether they define atypical clinical cases.
To identify whether large, rare CNVs in attention-deficit hyperactivity disorder (ADHD) are confined to a distinct clinical subgroup.
A total of 567 children with ADHD aged 5–17 years were recruited from community clinics. Psychopathology was assessed using the Child and Adolescent Psychiatric Assessment. Large, rare CNVs (>500 kb, <1% frequency) were defined from single nucleotide polymorphism data.
Copy number variant carriers (13.6%) showed no differences from non-carriers in ADHD symptom severity, symptom type, comorbidity, developmental features, family history or pre-/ perinatal markers. The only significant difference was a higher rate of intellectual disability (24% v. 9%, χ2 = 15.5, P = 0.001). Most CNV carriers did not have intellectual disability.
Large, rare CNVs are not restricted to an atypical form of ADHD but may be more highly enriched in children with cognitive problems.
Some research suggests that children with attention-deficit hyperactivity
disorder (ADHD) have a higher than expected risk of bipolar affective
disorder. No study has examined the prevalence of bipolar disorder in a
UK sample of children with ADHD.
To examine the prevalence of bipolar disorder in children diagnosed with
ADHD or hyperkinetic disorder.
Psychopathology symptoms and diagnoses of bipolar disorder were assessed
in 200 young people with ADHD (170 male, 30 female; age 6–18 years, mean
11.15, s.d. = 2.95). Rates of current bipolar disorder symptoms and
diagnoses are reported. A family history of bipolar disorder in parents
and siblings was also recorded.
Only one child, a 9-year-old boy, met diagnostic criteria for both ICD–10
hypomania and DSM–IV bipolar disorder not otherwise specified.
In a UK sample of children with ADHD a current diagnosis of bipolar
disorder was uncommon.
The neurodevelopmental hypothesis of schizophrenia provided a valuable
framework that allowed a condition that usually presents with frank disorder
in adolescence or early adulthood to be understood at least in part as a
consequence of events occurring early in development. However, the
implications of the neurodevelopmental hypothesis for nosological
conceptions of the disorder can only now be fully appreciated. Recent
research indicates genetic overlap between schizophrenia and syndromes in
which psychopathology is manifest in childhood and that are often grouped
together as ‘neurodevelopmental disorders' such as autism-spectrum
disorders, intellectual disability and attention-deficit hyperactivity
disorder. These findings challenge the aetiological basis of current
diagnostic categories and, together with evidence for frequent comorbidity,
suggest that we should view the functional psychoses as members of a group
of related and overlapping syndromes that result in part from a combination
of genetic and environmental effects on brain development and that are
associated with specific and general impairments of cognitive function. This
has important implications for future research and for the configuration of
Psychiatrists make important and specific contributions to the care of those
with mental health problems and high-quality services should enable patients
to benefit optimally from a psychiatrist's distinctive skills. In this
article we seek to identify and consider the core expertise of the
Attention-deficit hyperactivity disorder (ADHD) is recognised as a
common, disabling condition. Little information is available regarding
the long-term outcomes for individuals with ADHD in the UK.
To examine the 5-year outcome for a UK cohort of children with diagnosed,
treated ADHD and identify whether maternal and social factors predict key
One hundred and twenty-six school-aged children (mean age 9.4 years, s.d.
= 1.7) diagnosed with ADHD were reassessed 5 years later during
adolescence (mean age 14.5 years, s.d. = 1.7) for ADHD, conduct disorder
and other antisocial behaviours.
Most adolescents (69.8%) continued to meet full criteria for ADHD, were
known to specialist services and exhibited high levels of antisocial
behaviour, criminal activity and substance use problems. Maternal
childhood conduct disorder predicted offspring ADHD continuity; maternal
childhood conduct disorder, lower child IQ and social class predicted
offspring conduct disorder symptoms.
The treatment and monitoring of ADHD need to be intensified as outcomes
are poor especially in offspring of mothers with childhood conduct
Many prenatal risk factors are known to have adverse consequences on fetal
development and there is increasing interest in effects on the mental health
of offspring. However, associations with prenatal risk factors may arise
because of postnatal risk or through confounders, including inherited ones.
As a result, caution is required in assuming causation.
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.
To examine psychopathy traits in ADHD.
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.
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.
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.