Maternal vitamin-D and omega-3 fatty acid (DHA) deficiencies during pregnancy have previously been associated with offspring neurodevelopmental traits. However, observational study designs cannot distinguish causal effects from confounding.

First, we conducted Mendelian randomisation (MR) using genetic instruments for vitamin-D and DHA identified in independent genome-wide association studies (GWAS). Outcomes were (1) GWAS for traits related to autism and ADHD, generated in the Norwegian mother, father, and child cohort study (MoBa) from 3 to 8 years, (2) autism and ADHD diagnoses. Second, we used mother–father–child trio-MR in MoBa (1) to test causal effects through maternal nutrient levels, (2) to test effects of child nutrient levels, and (3) as a paternal negative control.

Associations between higher maternal vitamin-D levels on lower ADHD related traits at age 5 did not remain after controlling for familial genetic predisposition using trio-MR. Furthermore, we did not find evidence for causal maternal effects of vitamin-D/DHA levels on other offspring traits or diagnoses. In the reverse direction, there was evidence for a causal effect of autism genetic predisposition on lower vitamin-D levels and of ADHD genetic predisposition on lower DHA levels.

Triangulating across study designs, we did not find evidence for maternal effects. We add to a growing body of evidence that suggests that previous observational associations are likely biased by genetic confounding. Consequently, maternal supplementation is unlikely to influence these offspring neurodevelopmental traits. Notably, genetic predisposition to ADHD and autism was associated with lower DHA and vitamin-D levels respectively, suggesting previous associations might have been due to reverse causation.

Copy number variants (CNVs) are large changes in the structure of DNA. Certain rare CNVs are associated with elevated chance of neurodevelopmental conditions and difficulties (NDs), including autism spectrum disorder (ASD) and intellectual disability, alongside various physical health complications. Currently, CNV testing in children with NDs is only recommended under limited circumstances, in part because their impact on outcomes and prognosis remains unknown. We aimed to investigate whether individuals with NDs in childhood, with and without rare pathogenic CNVs, differ in terms of functional outcomes in early adulthood.

Pathogenic CNV carriers were identified in the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK birth cohort of individuals born in 1991–1992. Individuals with the following childhood NDs were identified through parent-reported diagnostic interviews and questionnaires, and assessment with the child: Attention Deficit Hyperactivity-Disorder (ADHD), ASD, reading difficulties, coordination difficulties, language difficulties, and chronic tics. Outcomes were measured at age 25 and included: presence of an emotional disorder, being in receipt of sickness/disability benefit, ability to make and maintain friendships, not being in education, employment, or training (NEET), and self-reported life satisfaction. We will use logistic regression to measure the association between carrying a pathogenic CNV and each functional outcome in ALSPAC. Sensitivity analyses will be conducted on all large (>250kb), rare (<1%) CNVs, as opposed to only pathogenic CNVs.

983 individuals with probable NDs (39.4% female, n = 387) were identified in ALSPAC, including 495 people with ASD, 163 with ADHD, 16 with Tourette's syndrome, 210 with reading difficulties, 295 with language difficulties, and 166 with coordination difficulties. Many individuals met criteria for more than one ND.

43 (4.4%) of individuals with an ND carried a pathogenic CNV. CNV carrier status amongst individuals with a ND was not associated with sex (4.4% of females vs 4.4% of males, OR = 1.007 [0.539–1.882] p = 0.981). Analysis of CNV carrier status on outcomes in NDs will be conducted between February and April 2024.

Evidence in support of poorer outcomes in CNV carriers could suggest that neurodiverse young people with CNVs may benefit from intervention to improve outcomes, and thus more individuals may benefit from genetic testing. Conversely, evidence indicating that CNVs do not impact outcomes may suggest that current clinical guidelines are appropriate within the current research landscape, and that further research is needed to understand the impact of carrying a pathogenic CNV in young people with NDs.

Sex differences in the prevalence of ADHD are well reported in the literature, with childhood ADHD being diagnosed 7–8 times more frequently in males than females, despite a population sex ratio of 3–4:1. A recent consensus statement argued that ADHD is under-identified and under-diagnosed in the UK, and this is especially concerning with regards to females. This systematic review aims to investigate specific symptoms characterising the manifestation of ADHD in females compared with both males with ADHD and females without ADHD.

A systematic search of eligible studies was conducted using predefined search criteria across six databases (Ovid MEDLINE, Ovid EMBASE, Ovid APA PsycINFO, ProQuest, EBSCO ERIC and EBSCO British Education Index), in line with a registration protocol on PROSPERO. Eligible studies included those with statistical analysis comparing ADHD, impact or co-occurring mental health difficulties at the item level, which compared ADHD symptoms in both sexes, or contrasted females with and without ADHD. Studies that exclusively reported total scores without item-level statistical results were excluded. A total of 5,378 articles were identified in the search and 13 studies met the criteria for inclusion.

Outcomes from 13 studies were analysed thematically. 7 studies looked at ADHD at an item level, while 7 studies explored disparities in impairment or other items. Of the eligible studies, 12 compared males and females with ADHD and 4 compared females with and without ADHD. 7 studies focussed on children with ADHD and 6 on adults. Preliminary results from 3 studies of ADHD symptoms in children indicated sex differences in hyperactive and impulsive symptoms: males were more likely to exhibit symptoms such as fidgeting and difficulty remain seated, while females exhibited higher rates of excessive talking and interrupting. Sex differences in impairment showed mixed results. Females with ADHD endorsed self-reported items related to mind-wandering and parent-reported impairment, including friendship difficulties, more than females without ADHD. Overall, the analysis of the results suggested that most studies do show some sex differences in ADHD and impairment items.

While current studies of individuals diagnosed with ADHD highlight important sex differences, the limited number of direct investigations and predominant focus on total symptoms underscore the need for further research. Item-level analysis of symptoms and their impact is essential in exploring how sex influences the associations between ADHD, risk factors and functional outcomes. Recognising potential sex differences is essential for improving ADHD assessment in females and later life outcomes.

It is well-known that childhood attention-deficit hyperactivity disorder (ADHD) is associated with later adverse mental health and social outcomes. Patient-based studies suggest that ADHD may be associated with later cardiovascular disease (CVD) but the focus of preventive interventions is unclear. It is unknown whether ADHD leads to established cardiovascular risk factors because so few cohort studies measure ADHD and also follow up to an age where CVD risk is evident.

To examine associations between childhood ADHD problems and directly measured CVD risk factors at ages 44/45 years in a UK population-based cohort study (National Child Development Study) of individuals born in 1958.

Childhood ADHD problems were defined by elevated ratings on both the parent Rutter A scale and a teacher-rated questionnaire at age 7 years. Outcomes were known cardiovascular risk factors (blood pressure, lipid measurements, body mass index and smoking) at the age 44/45 biomedical assessment.

Of the 8016 individuals assessed both during childhood and at the biomedical assessment 3.0% were categorised as having childhood ADHD problems. ADHD problems were associated with higher body mass index (B = 0.92 kg/m2, s.d. = 0.27–1.56), systolic (3.5 mmHg, s.d. = 1.4–5.6) and diastolic (2.2 mmHg, s.d. = 0.8–3.6) blood pressure, triglyceride levels (0.24 mol/l, s.d. = 0.02–0.46) and being a current smoker (odds ratio OR = 1.6, s.d. = 1.2–2.1) but not with LDL cholesterol.

Childhood ADHD problems predicted multiple cardiovascular risk factors by mid-life. These findings, when taken together with previously observed associations with cardiovascular disease in registries, suggest that individuals with ADHD could benefit from cardiovascular risk monitoring, given these risk factors are modifiable with timely intervention.

Current psychiatric diagnoses, although heritable, have not been clearly mapped onto distinct underlying pathogenic processes. The same symptoms often occur in multiple disorders, and a substantial proportion of both genetic and environmental risk factors are shared across disorders. However, the relationship between shared symptoms and shared genetic liability is still poorly understood.

Well-characterised, cross-disorder samples are needed to investigate this matter, but few currently exist. Our aim is to develop procedures to purposely curate and aggregate genotypic and phenotypic data in psychiatric research.

As part of the Cardiff MRC Mental Health Data Pathfinder initiative, we have curated and harmonised phenotypic and genetic information from 15 studies to create a new data repository, DRAGON-Data. To date, DRAGON-Data includes over 45 000 individuals: adults and children with neurodevelopmental or psychiatric diagnoses, affected probands within collected families and individuals who carry a known neurodevelopmental risk copy number variant.

We have processed the available phenotype information to derive core variables that can be reliably analysed across groups. In addition, all data-sets with genotype information have undergone rigorous quality control, imputation, copy number variant calling and polygenic score generation.

DRAGON-Data combines genetic and non-genetic information, and is available as a resource for research across traditional psychiatric diagnostic categories. Algorithms and pipelines used for data harmonisation are currently publicly available for the scientific community, and an appropriate data-sharing protocol will be developed as part of ongoing projects (DATAMIND) in partnership with Health Data Research UK.

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.

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.

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.

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.