Childhood neurodevelopmental problems and adolescent bully victimization: population-based, prospective twin study in Sweden

Research Review: A review of the past decade of family and genomic studies on adolescent mental health

BACKGROUND

Mental health problems and traits capturing psychopathology are common and often begin during adolescence. Decades of twin studies indicate that genetic factors explain around 50% of individual differences in adolescent psychopathology. In recent years, significant advances, particularly in genomics, have moved this work towards more translational findings.

METHODS

This review provides an overview of the past decade of genetically sensitive studies on adolescent development, covering both family and genomic studies in adolescents aged 10-24 years. We focus on five research themes: (1) co-occurrence or comorbidity between psychopathologies, (2) stability and change over time, (3) intergenerational transmission, (4) gene-environment interplay, and (5) psychological treatment outcomes.

RESULTS

First, research shows that much of the co-occurrence of psychopathologies in adolescence is explained by genetic factors, with widespread pleiotropic influences on many traits. Second, stability in psychopathology across adolescence is largely explained by persistent genetic influences, whereas change is explained by emerging genetic and environmental influences. Third, contemporary twin-family studies suggest that different co-occurring genetic and environmental mechanisms may account for the intergenerational transmission of psychopathology, with some differences across psychopathologies. Fourth, genetic influences on adolescent psychopathology are correlated with a wide range of environmental exposures. However, the extent to which genetic factors interact with the environment remains unclear, as findings from both twin and genomic studies are inconsistent. Finally, a few studies suggest that genetic factors may play a role in psychological treatment response, but these findings have not yet been replicated.

CONCLUSIONS

Genetically sensitive research on adolescent psychopathology has progressed significantly in the past decade, with family and twin findings starting to be replicated at the genomic level. However, important gaps remain in the literature, and we conclude by providing suggestions of research questions that still need to be addressed.

Understanding the prospective associations between neuro-developmental problems, bullying victimization, and mental health: Lessons from a longitudinal study of institutional deprivation

Studies suggest that children who have experienced neglect are at risk for bullying which in turn increases the risk for poor mental health. Here we extend this research by examining whether this risk extends to the neglect associated with severe institutional deprivation and then testing the extent to which these effects are mediated by prior deprivation-related neuro-developmental problems such as symptoms of inattention, hyperactivity and autism. Data were collected at ages 6, 11, 15, and young adulthood (22-25 years) from 165 adoptees who experienced up to 43 months of deprivation in Romanian Orphanages in 1980s and 52 non-deprived UK adoptees (N = 217; 50.23% females). Deprivation was associated with elevated levels of bullying and neuro-developmental symptoms at ages 6 through 15 and young adult depression and anxiety. Paths from deprivation to poor adult mental health were mediated via cross-lagged effects from earlier neuro-developmental problems to later bullying. Findings evidence how deep-seated neuro-developmental impacts of institutional deprivation can cascade across development to impact social functioning and mental health. These results elucidate cascade timing and the association between early deprivation and later bullying victimization across childhood and adolescence.

Below average motor skills predict victimization from childhood bullies: A study of adults with ADHD

Children with ADHD are frequently clumsy and involved in bullying, both as victims and perpetrators. The relationship between motor skills and bully status is poorly understood. The aim of the current study was to evaluate the effect of motor skills in childhood on bully victimization/perpetration in those with ADHD. In this cross-sectional study, 403 adults diagnosed with ADHD filled out a questionnaire on their recall of bully victimization, bully perpetration, performance in physical education (PE) (defined as performance below average in i.e., ball dexterity, coordination or agility) as a proxy for motor skills, and academic skills at age 12, as compared to their peers. Of the current sample, 63% remembered being victimized and 31% noted they were perpetrators. Thirty-two percent recalled that they performed below average in PE. Being diagnosed with ADHD and having poor motor skills was strongly associated with bully victimization (OR = 2.63; 95% CI:1.62, 4.27, p < .001). Victimization was more common during all measured time periods, from nursery school until the age of 15, among those with poor performance in PE as compared to those without poor performance. No relationship was found between poor motor skills and bully perpetration. CONCLUSION: A crucial role of the cerebellum is coordination and the linking of sequenced motor actions through milli-second timing. Aberrations in this ability makes a person present as "different", which was stated as the most common reason for social exclusion by other children. Therefore, subtle clumsiness (presumed by poor performance in PE class) is suggested to mirror deficits in social skills, which is intuitively observed by peers, leading to victimization.

Associations between poor gross and fine motor skills in pre-school and peer victimization concurrently and longitudinally with follow-up in school age - results from a population-based study

BACKGROUND

Children with poor motor skills are at increased risk of peer victimization. However, it is unclear whether poor gross and fine motor skills are differently linked to peer victimization among pre-school and schoolchildren.

AIMS

To investigate associations between poor gross and fine motor skills measured in pre-school and the associations to peer victimization measured concurrently and in school age.

SAMPLE

Data from the Norwegian Mother, Father and Child Cohort Study (MoBa), and the Medical Birth Registry of Norway were used. Participants with complete questionnaires at 3, 5, and 8 years (n = 23 215) were included.

METHODS

A longitudinal design and an autoregressive cross-lagged model were used to investigate if poor gross and fine motor skills at 3 and 5 years predicted peer victimization at 5 and 8 years. Because emotional difficulties are associated with both motor skills and peer victimization, the results were adjusted for emotional difficulties.

RESULTS

Only poor fine motor skills at 3 years had a significant association to peer victimization at 5 years. Poor gross motor skills at 5 years had a stronger association to peer victimization measured concurrently compared to poor fine motor skills, and only poor fine motor skills at 5 years was significantly linked to peer victimization at 8 years. No gender difference was found between these paths.

CONCLUSIONS

Teachers and parents should be aware that motor skills predict peer victimization, and that poor gross and fine motor skills have different associations to peer victimization measured at different ages.

A Co-Twin Control Study of the Association Between Bullying Victimization and Self-Harm and Suicide Attempt in Adolescence

PURPOSE

The aim of the study was to investigate the magnitude of an independent association between bullying victimization and self-harm and suicide attempt in adolescence after adjusting for unmeasured and measured confounding factors.

METHODS

Using the Child and Adolescent Twin Study in Sweden, we examined twins born between 1994 and 1999 (n = 13,852). Twins self-reported bullying victimization at age 15 years and self-harm and suicide attempt at age 18 years. We created a factor score of 13 bullying items, on which self-harm and suicide attempt items were regressed in three models: (1) among unrelated individuals; (2) among co-twins, in which a twin exposed to more bullying was compared with his/her co-twin who was exposed to less; and (3) among co-twins while adjusting for indicators of childhood psychopathology.

RESULTS

Among unrelated individuals, a one standard deviation increase in bullying victimization was associated with increased odds for self-harm (odds ratio [OR], 1.29 [95% confidence interval, 1.23-1.36]) and suicide attempt (OR, 1.68 [1.53-1.85]). Among co-twins, the odds attenuated for self-harm (OR, 1.19 [1.09-1.30]) and suicide attempt (OR, 1.39 [1.17-1.66]). Finally, when accounting for childhood psychopathology, there was a 14% (1.04-1.25) and 25% (1.03-1.52) relative increase in odds of self-harm and suicide attempt, respectively.

CONCLUSIONS

The results suggest that bullying victimization was uniquely associated with self-harm and suicide attempt over and above the confounding because of unmeasured and measured factors (i.e., familial vulnerability and pre-existing psychopathy). However, magnitudes were small, suggesting that additional interventions and screenings are needed to address suicidality apart from bullying interventions.

Psychosis Risk and Development: What Do We Know From Population-Based Studies?

Recent years have seen an advent in population-based studies in children, adolescents, and adults that examine the prevalence, etiology, and developmental trajectories of diverse subclinical psychopathological symptoms that pose a risk for the later development of severe mental illnesses. It is increasingly recognized that most categorically defined psychiatric disorders occur on a spectrum or continuum, show high heterogeneity and symptom overlap, and share genetic and environmental risk factors. We discuss neurodevelopmental underpinnings of psychosis spectrum symptoms and review brain morphometric and functional alterations as well as genetic liability for psychosis in individuals experiencing psychotic symptoms (PSs) in the general population. With regard to brain structure and function, findings of qualitatively similar alterations in individuals experiencing subthreshold PSs and individuals with overt psychotic disorders support the notion of a psychosis continuum. However, genetic and epidemiological studies have emphasized the overlap of PSs and other psychiatric illnesses. In particular, PSs during adolescence appear to be a nonspecific precursor of different psychopathological outcomes. Given the evidence presented in this review, we argue that findings from population-based studies are appropriate to guide policy-making to further emphasize public health efforts. Broadly accessible mental health programs are promising to make a difference in the field of adolescent mental health. However, the specific efficacy of these programs warrants further study, and caution is advised to not overpathologize potentially transient occurrence of mental health problems.

Peer-Victimization of Young Children With Developmental and Behavioral Difficulties-A Population-Based Study

OBJECTIVE

The aim is to investigate if young children with developmental and behavioral difficulties (DBDs) have greater risk of peer-victimization compared with typically developing (TD) children.

METHOD

The sample was drawn from the Norwegian Mother and Child Cohort Study (MoBa). MoBa has collected population-based data on children's health and development for 114,500 children. We included children that were 5 years of age (n = 41,609). Multivariate logistic regression was used to estimate the effect of different DBDs and of co-occurring DBDs on peer-victimization compared with TD children. Categories of DBDs included autistic traits, emotional difficulties, behavioral difficulties, general learning difficulties, attention difficulties/impulsive behavior, motor development difficulties, language difficulties, and hearing and vision difficulties. Results were adjusted for socioeconomic status and the child's sex.

RESULTS

Peer-victimization was 2.8% (933) among TD children, and 8.0% (615) among children with DBD. The highest risk of peer-victimization was found among children with autistic traits and children with five or more co-occurring DBDs (adjusted odds ratios [ORs] = 12.76; 95% confidence interval [CI] 8.64-18.84; p ≤ .001) and 17.37 (95% CI 12.15-24.82; p ≤ .001)], respectively. The lowest risk was found among children with hearing and vision difficulties and children with only one DBD [adjusted ORs = 1.98 (95% CI 1.71-2.29; p ≤ .001) and 1.95 (95% CI 1.70-2.22; p ≤ .001)].

CONCLUSION

Children with DBD have a substantially higher risk of peer-victimization compared with TD children. Peer-victimization varies with type of DBD and increases cumulatively by number of DBDs.

Heritability of Bullying and Victimization in Children and Adolescents: Moderation by the KiVa Antibullying Program

Objective: Bullying affects approximately a quarter of schoolchildren and is associated with numerous adverse outcomes. Although distinct risk factors for bullying and victimization have been identified, few studies have investigated the genetic and environmental underpinnings of bullying and victimization. The aims of this study were twofold: first, to examine the contributions of genetic and environmental factors to bullying and victimization, and second, to analyze whether the KiVa antibullying program moderated the magnitude of these contributions by comparing estimates derived from the KiVa versus control groups.Method: The sample comprised students from schools that participated in the evaluation of the KiVa antibullying program in Finland during 2007-2009. Bullying and victimization were measured using peer nominations by classmates. The sample for the twin analyses comprised of 447 twins (107 monozygotic and 340 dizygotic twins) aged 7-15.Results: Genetic contributions accounted for 62% and 77% of the variance in bullying and in victimization at pre-intervention, respectively. There was a post-intervention difference in the overall role of genetic and environmental contributions between the intervention and the control group for bullying and victimization, with non-shared environmental effects playing a lesser role (and genes a larger role) in the intervention than in the control group context.Conclusions: This study replicates previous findings on the genetic underpinnings of both bullying and victimization, and indicates that a school-based antibullying program reduces the role of non-shared environmental factors in bullying and victimization. The results indicate that prevention and intervention efforts need to target both environmental and (heritable) individual level factors to maximize effectiveness.

Childhood neurodevelopmental disorders and risk of coercive sexual victimization in childhood and adolescence - a population-based prospective twin study

BACKGROUND

Autism spectrum disorder (ASD), Attention-deficit/Hyperactivity disorder (ADHD), and other related neurodevelopmental disorders (NDDs) have, in some previous studies, been shown to increase the risk of being sexually victimized. However, no studies have examined whether the association is driven by a general NDD phenotype versus specific diagnoses, nor the etiology of the association.

METHOD

Using a genetically informative, prospective design, we examined the association between ASD and ADHD in childhood and coercive sexual victimization up to age 18. A total of 4,500 children participating in the Child and Adolescent Twin Study in Sweden (CATSS) were rated by their parents on NDDs at age 9 or 12 years, and self-reported at age 18 on lifetime experiences of coercive sexual touching and/or coercive sex. First, we regressed sexual victimization on the NDDs. Second, we regressed sexual victimization on general and specific NDD symptoms identified via a bifactor model. Third, we decomposed the observed associations into genetic and environmental parts.

RESULTS

In females, ASD was associated with an almost threefolded increased risk of coercive sexual victimization, and ADHD with a doubled risk. In males, the risk associated with ASD and ADHD was of the same magnitude but not significant. When controlling for overall NDD symptom load ASD or ADHD, no longer uniquely predicted coercive sexual victimization. The association between the NDD general factor and coercive sexual victimization was due to shared genetics.

CONCLUSIONS

General NDD symptom load, rather than specific ASD or ADHD symptoms, seems to be a moderate vulnerability factor for coercive sexual victimization. We speculate that an evocative gene-environment correlation might account for this observation, such that sexual perpetrators actively target NDD individuals.