Young Adult ADHD Symptoms in the General Population and Neurocognitive Impairment.

OBJECTIVE: Neurocognitive impairments are associated with child and adult ADHD in clinical settings. However, it is unknown whether adult ADHD symptoms in the general population are associated with the same pattern of cognitive impairment. We examined this using a prospective, population-based cohort spanning birth to age 25 years. METHODS: We examined associations between self-reported adult ADHD symptoms and cognitive task performance (attention and response inhibition) in adulthood and childhood. RESULTS: Self-rated ADHD symptoms at age 25 were associated with poorer performance in age 25 cognitive tasks capturing ADHD-related functioning (attention B = -0.03, 95% CI [0.05, -0.01], p = .005; response inhibition B = -0.03, 95% CI [-0.05, -0.01], p = .002). CONCLUSIONS: Neurocognitive impairments linked to adult ADHD symptoms in the general population, are similar to those found in people with childhood ADHD symptoms and are consistent with findings in adult ADHD clinical samples.

Following the children of depressed parents from childhood to adult life: A focus on mood and anxiety disorders.

Background: Parental depression increases risk for anxiety and depression in offspring. The transition from adolescence to adulthood is a common risk period for onset of such disorders. However, relatively few studies have considered development of these disorders from childhood to adulthood including multiple assessments during this transition period. Method: Offspring of depressed parents aged 9-17 years at baseline were followed prospectively for 13 years (n = 337). Average length of follow-up was 16 months between the first and second waves, 13 months between the second and third, and 8 years between the third and fourth. Current (3-month) psychopathology was assessed at each wave using diagnostic interviews. We derived estimates of 3-month prevalence, age at first diagnosis, course and comorbidity of disorders. Social functioning in adult life was assessed at the final wave and we assessed how prior and current disorder impacted adult functioning. Results: A quarter of young people met criteria for a mood disorder and a third for anxiety disorder at least once. Mood and anxiety disorder prevalence increased from 4.5% and 15.8% respectively in childhood (9-11 years) to 22.3% and 20.9% respectively by age 23-28. Increased prevalence across the transition from adolescence to adulthood was particularly marked in males, while prevalence increased earlier in adolescence in females. Age at first diagnosis varied widely (mood disorder mean = 16.5 years (range 9-26); anxiety disorder mean = 14.5 years (range 9-28)). Over half (52%) reported functional impairment in early adulthood, 31% harmful alcohol use, and 10% self-harm or a suicide attempt. Both previous and current mood or anxiety disorder were associated with functional impairment in early adulthood. Conclusions: There is a prolonged risk period for mood and anxiety disorders in this group, with prevalence peaking in early adulthood. This highlights the need for prolonged vigilance and effective targeted interventions in the offspring of depressed parents.

Validation of the Strengths and Difficulties Questionnaire (SDQ) emotional subscale in assessing depression and anxiety across development.

Emotional disorders are common in childhood, and their prevalence sharply increases during adolescence. The Strengths and Difficulties Questionnaire (SDQ) is widely used for screening emotional and behavioural difficulties in children and young people, but little is known about the accuracy of the emotional subscale (SDQ-E) in detecting emotional disorders, and whether this changes over development. Such knowledge is important in determining whether symptom changes across age are due to developmental or measurement differences. This study assessed the validity of the SDQ-E and two individual items (low mood and general worry) in differentiating between cases and non-cases of Major Depressive Disorder (MDD), Generalised Anxiety Disorder (GAD), and other anxiety disorders across ages 7, 10, 13, 15, and 25 years in a UK population cohort. Analyses showed moderate accuracy of the subscale in discriminating cases of MDD (AUC = 0.67-0.85), and high accuracy for discriminating cases of GAD (AUC = 0.80-0.93) and any anxiety disorder (AUC = 0.74-0.83) compared to non-cases. The SDQ-E performed well across ages and sex, and generally performed better than the two individual items. Together our findings validate the SDQ-E as a screen for emotional disorders during childhood, adolescence, and early adulthood, and as a tool for longitudinal research on depression and anxiety disorders.

Childhood attention-deficit hyperactivity disorder problems and mid-life cardiovascular risk: prospective population cohort study.

BACKGROUND: 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. AIMS: 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. METHOD: 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. RESULTS: 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. CONCLUSIONS: 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.

Characterising depression trajectories in young people at high familial risk of depression.

BACKGROUND: Parental depression is a common and potent risk factor for depression in offspring. However, the developmental course of depression from childhood to early-adulthood has not been characterized in this high-risk group. METHODS: Using longitudinal data from 337 young people who had a parent with a history of recurrent major depressive disorder (MDD), we characterized trajectories of broadly defined depressive disorder using latent class growth analysis. We used clinical descriptions to further characterise trajectory classes. RESULTS: Two trajectory classes were identified: childhood-emerging (25 %) and adulthood-emerging (75 %). The childhood-emerging class showed high rates of depressive disorder from age 12.5, which persisted through the study period. The adulthood-emerging class showed low rates of depressive disorder until age 26. Individual factors (IQ and ADHD symptoms) and parent depression severity (comorbidity, persistence and impairment) differentiated the classes but there were no differences in family history score or polygenic scores associated with psychiatric disorder. Clinical descriptions indicated functional impairment in both classes, but more severe symptomatology and impairment in the childhood-emerging class. LIMITATIONS: Attrition particularly affected participation in young adulthood. Factors associated with attrition were low family income, single parent household status and low parental education. CONCLUSIONS: The developmental course of depressive disorder in children of depressed parents is variable. When followed up to adult life, most individuals exhibited some functional impairment. An earlier age-of-onset was associated with a more persistent and impairing course of depression. Access to effective prevention strategies is particularly warranted for at-risk young people showing early-onsetting and persistent depressive symptoms.

Developing and validating a prediction model of adolescent major depressive disorder in the offspring of depressed parents.

BACKGROUND: Parental depression is common and is a major risk factor for depression in adolescents. Early identification of adolescents at elevated risk of developing major depressive disorder (MDD) in this group could improve early access to preventive interventions. METHODS: Using longitudinal data from 337 adolescents at high familial risk of depression, we developed a risk prediction model for adolescent MDD. The model was externally validated in an independent cohort of 1,384 adolescents at high familial risk. We assessed predictors at baseline and MDD at follow-up (a median of 2-3 years later). We compared the risk prediction model to a simple comparison model based on screening for depressive symptoms. Decision curve analysis was used to identify which model-predicted risk score thresholds were associated with the greatest clinical benefit. RESULTS: The MDD risk prediction model discriminated between those adolescents who did and did not develop MDD in the development (C-statistic = .783, IQR (interquartile range) = .779, .778) and the validation samples (C-statistic = .722, IQR = -.694, .741). Calibration in the validation sample was good to excellent (calibration intercept = .011, C-slope = .851). The MDD risk prediction model was superior to the simple comparison model where discrimination was no better than chance (C-statistic = .544, IQR = .536, .572). Decision curve analysis found that the highest clinical utility was at the lowest risk score thresholds (0.01-0.05). CONCLUSIONS: The developed risk prediction model successfully discriminated adolescents who developed MDD from those who did not. In practice, this model could be further developed with user involvement into a tool to target individuals for low-intensity, selective preventive intervention.

The antecedents and outcomes of persistent and remitting adolescent depressive symptom trajectories: a longitudinal, population-based English study.

BACKGROUND: Depression often first emerges in adolescence and, for many, is a lifelong disorder. The long-term clinical course of depression is highly variable. We aimed to examine the adult outcomes of adolescent-onset trajectories of clinically significant depressive symptoms and to identify factors differentiating trajectories that persist and desist in adulthood. METHODS: We included participants from the English population-based Avon Longitudinal Study of Parents and Children with data on depressive symptoms. Self-reported depression symptoms were assessed on ten occasions when participants were age 10·5-25 years using the short Mood and Feelings Questionnaire, and major depressive disorder episodes were assessed at age 13·0 years, 15·0 years, 17·5 years, and 25·0 years. We characterised trajectories of depression symptoms using latent class growth analysis, for which we required depression data at least once from each of three key phases: ages 10·5-13·5 years; 16·5-18·5 years; and 21-25 years. We examined adult outcomes by assessing lifetime suicidal self-harm and functional impairment at age 24·0 years, and employment, education, and the self-reported Strengths and Difficulties Questionnaire at age 25·0 years. FINDINGS: We studied 4234 participants: 2651 (63%) female, 1582 (37%) male, and one individual with missing sex data. The mean age was 10·6 years (SD 0·2) at baseline and 25·8 years (SD 0·5) at the final timepoint. Data on ethnicity were not available in our data set. We identified four depression trajectory classes: adolescent-persistent depression with onset early in adolescence (7%, n≈279), adolescent-limited depression with onset later in adolescence and remittance by adult life (14%, n≈592), adult-increasing depression (25%, n≈1056), and stable-low levels of depression (54%, n≈2307). The adolescent-persistent class was associated with poor adult outcomes for functional impairment (62%), suicidal self-harm (27%), mental health difficulties (25%), and not being in education, employment, or training (16%). Adolescent-limited depression was associated with transient adolescent stress, but by early adulthood functional impairment and mental health difficulties were similar to the stable-low group. Major depressive disorder polygenic score (odds ratio [OR] 1·36, 95% CI 1·04-1·79), adolescent educational attainment (OR 0·47, 0·30-0·74), and any early childhood adversity (OR 2·60, 1·42-4·78), that persisted into adulthood (OR 1·60, 1·38-1·87) distinguished the adolescent-persistent and adolescent-limited groups. INTERPRETATION: The future course of adolescent depression can be differentiated by age at onset during adolescence, adolescent academic attainment, early and persistent adversity, and genetic loading. A detailed social and educational history could be helpful in making clinical decisions about the intensity of interventions for young people with clinically elevated depressive symptoms who seek help. FUNDING: Medical Research Council, Wolfson Centre for Young People's Mental Health, Wolfson Foundation.

Validation of the short Mood and Feelings Questionnaire in young adulthood.

BACKGROUND: Depression often onsets in adolescence and is associated with recurrence in adulthood. There is a need to identify and monitor depression symptoms across adolescence and into young adulthood. The short Mood and Feelings Questionnaire (sMFQ) is commonly used to measure depression symptoms in adolescence but has not been validated in young adulthood. This study aimed to (1) examine whether the sMFQ is valid in young adulthood, and (2) identify cut-points best capturing DSM-5 depression diagnosis at age 25 METHODS: The sample included participants in the Avon Longitudinal Study of Parents and Children (ALSPAC) at age 25 (n = 4098). Receiver Operating Characteristic analyses examined how well the self-rated sMFQ discriminates between cases and non-cases of DSM-5 Major Depressive Disorder (MDD) classified using the self-rated Development and Well Being Assessment. Sensitivity and specificity values were used to identify cut-points on the sMFQ RESULTS: The sMFQ had high accuracy for discriminating MDD cases from non-cases at age 25. The commonly used cut-point in adolescence (≥12) performed well at this age, best balancing sensitivity and specificity. However, a lower cut-point (≥10) may be appropriate when favouring sensitivity over specificity e.g., in context of screening. Sensitivity analyses suggested similar results for males and females LIMITATIONS: ALSPAC is a longitudinal population cohort that suffers from non-random attrition CONCLUSIONS: The sMFQ is a valid measure of depression in young adults in the general population. It can be used to screen for and monitor depression across adolescence and early adulthood.

Investigating the validity of the Strengths and Difficulties Questionnaire to assess ADHD in young adulthood.

Attention Deficit Hyperactivity Disorder (ADHD) symptoms typically onset early and persist into adulthood for many. Robust investigation of symptom continuity and discontinuity requires repeated assessments using the same measure, but research is lacking into whether measures used to assess ADHD symptoms in childhood are also valid in adulthood. The Strengths and Difficulties Questionnaire (SDQ) is widely used to assess ADHD symptoms in children, but little is known about its utility in adulthood. The aim of this study was to assess the validity of the SDQ hyperactivity/ADHD subscale to distinguish between cases and non-cases of DSM-5 ADHD at age 25 years in a UK population cohort (N = 4121). ADHD diagnosis was derived using the Barkley Adult ADHD Rating Scale-IV. Analyses suggested that the self-rated SDQ ADHD subscale had high validity in distinguishing ADHD cases/non-cases in young adulthood (area under the curve=0.90, 95% CI=0.87-0.93) and indicated a lower cut-point for identifying those who may have an ADHD diagnosis in this age group compared to that currently recommended for younger ages. Findings were similar for parent-reports. Our findings suggest that the SDQ is suitable for ADHD research across different developmental periods, which will aid the robust investigation of ADHD from childhood to young adulthood.

Variable Emergence of Autism Spectrum Disorder Symptoms From Childhood to Early Adulthood.

OBJECTIVE: Autism spectrum disorder (ASD) is currently considered an early-onset neurodevelopmental condition. Follow-up studies of clinic-ascertained autism suggest that autistic symptoms typically decline with age, although symptom improvement is limited for some. To date there have been no population-based prospective studies investigating the natural history of autistic symptoms from childhood to adulthood. The aim of this study was to characterize the development and heterogeneity of autistic symptoms in a population-based cohort from childhood to age 25. METHODS: Data were analyzed in a prospective U.K. population-based cohort (ALSPAC). Trajectories were derived using five assessments of the parent-rated Social and Communication Disorders Checklist (SCDC) spanning ages 7-25. Additional measures were used to validate symptom trajectories. RESULTS: Three distinct SCDC symptom trajectory classes were identified: low (88.5%), declining (5.0%), and late-emerging (6.5%). Both the declining and late-emerging trajectory classes were associated with child and adult ASD measures, low IQ, communication problems, peer problems, and worse adult functioning compared with the low trajectory class. Male sex was associated with a higher likelihood of being in the declining trajectory class (odds ratio=2.84, 95% CI=2.19, 3.69). This sex difference was not observed in the late-emerging class (odds ratio=1.00, 95% CI=0.80, 1.24) compared with the low trajectory class. CONCLUSIONS: ASD symptom levels that emerged early tended to decline across development, although impairment was still present in adulthood for some. For others, autistic symptoms emerged across adolescence and adulthood. This challenges our current understanding that ASD symptoms inevitably first manifest early in development.

The Effect of Attention Deficit/Hyperactivity Disorder on Physical Health Outcomes: A 2-Sample Mendelian Randomization Study.

Attention-deficit/hyperactivity disorder (ADHD) is associated with a broad range of physical health problems. Using different research designs to test whether ADHD has a causal role in these associations is important because comorbid health problems increase the serious social and economic impacts of ADHD. We used 2-sample Mendelian randomization (MR) to infer causal relationships between ADHD and previously implicated physical health conditions. Different MR methods were used to test the robustness and plausibility of our findings. Consistent findings underwent bidirectional and multivariable MR. We found evidence of ADHD having a causal effect on childhood obesity (odds ratio = 1.29, 95% confidence interval: 1.02, 1.63) and coronary artery disease (odds ratio = 1.11, 95% confidence interval: 1.03, 1.19) with consistent results across MR approaches. There was additional MR evidence for a bidirectional relationship between ADHD and childhood obesity. The relationship with coronary artery disease attenuated when controlling for childhood obesity. There was little evidence for inferring a causal effect on other cardiometabolic, autoimmune, allergic, and neurological diseases. Our findings strengthen the argument for effective treatment of children with ADHD, and suggest that clinicians who manage ADHD need to be aware of the risk of childhood obesity to reduce future risks of coronary artery disease.

ADHD and depression: investigating a causal explanation.

BACKGROUND: 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. 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. RESULTS: 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). CONCLUSIONS: 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.

Assessment of age-at-onset criterion for adult attention-deficit hyperactivity disorder.

To investigate the accuracy of the age-at-onset criterion in those who meet other DSM-5 criteria for attention-deficit hyperactivity disorder, using a prospective population cohort we compared four different approaches to asking those aged 25 years (n = 138) when their symptoms started. Receiver operating characteristic curves showed variation between the approaches (χ(3) = 8.99, P = 0.03); all four showed low discrimination against symptoms that had been assessed when they were children (area under the curve: 0.57-0.68). Asking adults to recall specific symptoms may be preferable to recalling at what age symptoms started. However, limitations to retrospective recall add to debate on the validity of ADHD age-at-onset assessment.

Investigating attention-deficit hyperactivity disorder and autism spectrum disorder traits in the general population: What happens in adult life?

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are generally considered early-onset disorders so most research has therefore tended to focus on children. Differences between ADHD/ASD in adult life and childhood have been noted, but few population-based studies have examined them in adulthood. Furthermore, the interpretation of findings is hampered by changes in measure and from parent report to self-report. METHOD: We examined continuous/trait measures of parent- and self-rated ADHD and ASD in adulthood (age 25 years) in a UK prospective longitudinal sample ALPSAC (the Avon Longitudinal Study of Parents and Children), using many of the same measures that parents reported on in childhood (N = 6,064). Our aim was to investigate these traits in this population for mean-level sex differences, overlaps with other cognitive, learning and communication problems and their associations with polygenic risk scores (PRS) for neuropsychiatric disorders (ADHD, ASD, schizophrenia, depression and anxiety). RESULTS: ADHD and ASD traits in adulthood, as in childhood, showed associations with childhood cognitive, learning and communication problems and adult communication/language measures, although less so for self-ratings than parent-ratings. Males had higher ADHD and ASD trait levels, but this was not as marked as in childhood. In adulthood, ADHD (both parent- and self-rated) and ASD (parent-rated) symptoms showed associations with ADHD PRS; self-reported ADHD also showed association with depression PRS, whereas self-reported ASD did not show strong PRS associations. CONCLUSIONS: Our findings suggest that in young adults, ADHD and ASD symptoms have similar characteristics as they do in childhood. Associations with other cognitive, learning and communication problems, and ADHD PRS were somewhat less pronounced for self-reported adult ADHD and ASD symptoms, suggesting that even at age 25, parent reports, where available, could be clinically useful.

A Digital Intervention for Adolescent Depression (MoodHwb): Mixed Methods Feasibility Evaluation.

BACKGROUND: Treatment and prevention guidelines highlight the key role of health information and evidence-based psychosocial interventions for adolescent depression. Digital health technologies and psychoeducational interventions have been recommended to help engage young people and to provide accurate health information, enhance self-management skills, and promote social support. However, few digital psychoeducational interventions for adolescent depression have been robustly developed and evaluated in line with research guidance. OBJECTIVE: We aimed to evaluate the feasibility, acceptability, and potential impact of a theory-informed, co-designed digital intervention program, MoodHwb. METHODS: We used a mixed methods (quantitative and qualitative) approach to evaluate the program and the assessment process. Adolescents with or at elevated risk of depression and their parents and carers were recruited from mental health services, school counselors and nurses, and participants from a previous study. They completed a range of questionnaires before and after the program (related to the feasibility and acceptability of the program and evaluation process, and changes in mood, knowledge, attitudes, and behavior), and their Web usage was monitored. A subsample was also interviewed. A focus group was conducted with professionals from health, education, social, and youth services and charities. Interview and focus group transcripts were analyzed using thematic analysis with NVivo 10 (QSR International Pty Ltd). RESULTS: A total of 44 young people and 31 parents or carers were recruited, of which 36 (82%) young people and 21 (68%) parents or carers completed follow-up questionnaires. In all, 19 young people and 12 parents or carers were interviewed. Overall, 13 professionals from a range of disciplines participated in the focus group. The key themes from the interviews and groups related to the design features, sections and content, and integration and context of the program in the young person's life. Overall, the participants found the intervention engaging, clear, user-friendly, and comprehensive, and stated that it could be integrated into existing services. Young people found the "Self help" section and "Mood monitor" particularly helpful. The findings provided initial support for the intervention program theory, for example, depression literacy improved after using the intervention (difference in mean literacy score: 1.7, 95% CI 0.8 to 2.6; P<.001 for young people; 1.3, 95% CI 0.4 to 2.2; P=.006 for parents and carers). CONCLUSIONS: Findings from this early stage evaluation suggest that MoodHwb and the assessment process were feasible and acceptable, and that the intervention has the potential to be helpful for young people, families and carers as an early intervention program in health, education, social, and youth services and charities. A randomized controlled trial is needed to further evaluate the digital program.

Adult mood problems in children with neurodevelopmental problems: evidence from a prospective birth cohort followed to age 50.

PURPOSE: Specific child neurodevelopmental (ND) disorders such as ADHD and learning problems are associated with concurrent and future (up to early adulthood) mood problems. However, it is unclear whether findings generalise to population traits as well as diagnoses, to general as well as specific neurodevelopmental domains, and whether risk associations extend to later adulthood or diminish with age. METHODS: We used data from a UK cohort of children born in 1958, the National Child Development Study (NCDS). ND problems were assessed at ages 7 and 11 years with parent- and teacher ratings of restlessness, hyperactivity and motor co-ordination difficulties, and by individual tests of reading, arithmetic and general cognitive ability. Mood (depression/anxiety) problems were assessed using the Malaise symptom screen at 23, 33, 42, and 50 years. Factor analyses were conducted to assess whether the specific neurodevelopmental domains could be aggregated into a general "ND" latent factor as well as specific factors. Associations with mood outcomes were then tested. RESULTS: A bi-factor model with a general "ND" latent factor and specific "motor" and "cognition" factors fits the data well. The specific cognition and motor factor scores were associated with mood problems in early adulthood only. The "ND" factor demonstrated associations with mood problems at each adult follow-up (men - age 23 years: ß = 0.17; age 33: ß = 0.16; age 42: ß = 0.14; age 50: ß = 0.16; women - 23 years: ß = 0.25; 33 years: ß = 0.26; 42 years: ß = 0.14; 50 years: ß = 0.16; all ps < 0.01). Interactions by sex indicated that the association between this general factor and mood problems was more pronounced for women than men at ages 23 years (ß = 0.09, p = 0.005) and 33 years (ß = 0.10, p = 0.003), but not at 42 or 50 years (ps > 0.8). CONCLUSIONS: Our results suggest that, in a population-based cohort, a general, childhood neurodevelopmental difficulty factor is stably associated with mood problems in adult life.

Using Genetics to Examine a General Liability to Childhood Psychopathology.

Psychiatric disorders show phenotypic as well as genetic overlaps. There are however also marked developmental changes throughout childhood. We investigated the extent to which, for a full range of early childhood psychopathology, a general "p" factor was explained by genetic liability, as indexed by multiple different psychiatric polygenic risk scores (PRS) and whether these relationships altered with age. The sample was a UK, prospective, population-based cohort with psychopathology data at age 7 (N = 8161) and age 13 (N = 7017). PRS were generated from large published genome-wide association studies. At both ages, we found evidence for a childhood "p" factor as well as for specific factors. Schizophrenia and attention-deficit/hyperactivity disorder (ADHD) PRS were associated with this general "p" factor at both ages but depression and autism spectrum disorder (ASD) PRS were not. We also found some evidence of associations between schizophrenia, ADHD and depression PRS with specific factors, but these were less robust and there was evidence for developmental changes.

Identifying Novel Types of Irritability Using a Developmental Genetic Approach.

OBJECTIVE: Irritability, which is strongly associated with impairment and negative outcomes, is a common reason for referral to mental health services but is a nosological and treatment challenge. A major issue is how irritability should be conceptualized. The authors used a developmental approach to test the hypothesis that there are several forms of irritability, including a "neurodevelopmental/ADHD-like" type, with onset in childhood, and a "depression/mood" type, with onset in adolescence. METHODS: Data were analyzed from the Avon Longitudinal Study of Parents and Children, a prospective U.K. population-based cohort. Irritability trajectory classes were estimated for 7,924 individuals with data at multiple time points across childhood and adolescence (four possible time points from approximately ages 7 to 15). Psychiatric diagnoses were assessed at approximately ages 7 and 15. Psychiatric genetic risk was indexed by polygenic risk scores (PRSs) for attention deficit hyperactivity disorder (ADHD) and depression, derived using large genome-wide association study results. RESULTS: Five irritability trajectory classes were identified: low (81.2%), decreasing (5.6%), increasing (5.5%), late-childhood limited (5.2%), and high-persistent (2.4%). The early-onset high-persistent trajectory was associated with male preponderance, childhood ADHD (odds ratio=108.64, 95% CI=57.45-204.41), and ADHD PRS (odds ratio=1.31, 95% CI=1.09-1.58). The adolescent-onset increasing trajectory was associated with female preponderance, adolescent depression (odds ratio=5.14, 95% CI=2.47-10.73), and depression PRS (odds ratio=1.20, 95% CI=1.05-1.38). Both the early-onset high-persistent and adolescent-onset increasing trajectory classes were associated with adolescent depression diagnosis and ADHD PRS. CONCLUSIONS: The developmental context of irritability may be important in its conceptualization: early-onset persistent irritability may be more neurodevelopmental/ADHD-like and later-onset irritability more depression/mood-like. These findings have implications for treatment as well as nosology.

Brief report: a comparison of child mental health inequalities in three UK population cohorts.

There are substantial health disparities between children from low and higher income families. The study aimed to test changes in child mental health inequalities across three large UK population cohorts of 11-year-old children assessed in 1999, 2004 and 2012 as part of the British Child and Adolescent Mental Health Surveys and Millennium Cohort Study. Child mental health was assessed using parent and teacher versions of the Strengths and Difficulties Questionnaire. There were substantial differences in parent and teacher reported symptom scores between children from low and higher income families in each cohort. Differences in parent-reported symptoms increased over time (ES 0.35 [95% CI 0.20, 0.49] in 1999, ES 0.39 [95% CI 0.17, 0.61] in 2004, ES 0.54 [95% CI 0.49, 0.58] in 2012); cohort interaction: p = 0.01). This study found that marked child mental health inequalities exist. The mental health gap between advantaged and disadvantaged children has not reduced over the last 20 years and may be getting worse.