Bullying Mediates Between Attention-Deficit/Hyperactivity Disorder in Childhood and Psychotic Experiences in Early Adolescence

Timo Hennig; Edo S. Jaya; Tania M. Lincoln

Disclosures

Schizophr Bull. 2017;43(5):1036-1044. 

In This Article

Abstract and Introduction

Abstract

Although a childhood diagnosis of attention-deficit/hyperactivity disorder (ADHD) is known to be linked to psychotic experiences and psychotic disorders in later life, the developmental trajectories that could explain this association are unknown. Using a sample from the prospective population-based Avon Longitudinal Study of Parents and Children (ALSPAC) (N = 8247), we hypothesized that the previously reported association of ADHD combined subtype in childhood and psychotic experiences in early adolescence is mediated by traumatic events and by involvement in bullying. Moreover, we expected this mediation to be specific to ADHD and tested this by comparison with specific phobia. Children with ADHD combined subtype at age 7 were more often involved in bullying at age 10 (OR 3.635, 95% CI 1.973–6.697) and had more psychotic experiences at age 12 (OR 3.362, 95% CI 1.781–6.348). Moreover, children who were involved in bullying had more psychotic experiences (2.005, 95% CI 1.684–2.388). Bullying was a significant mediator between ADHD and psychotic experiences accounting for 41%–50% of the effect. Traumatic events from birth to age 11 were also significantly associated with ADHD combined subtype and psychotic experiences; however, there was no evidence of mediation. Specific phobia was significantly associated with psychotic experiences, but not with bullying. To conclude, bullying is a relevant translating mechanism from ADHD in childhood to psychotic experiences in early adolescence. Interventions that eliminate bullying in children with ADHD could potentially reduce the risk of having psychotic experiences in later life by up to 50%. Clinicians should thus screen for bullying in routine assessments of children with ADHD.

Introduction

Attention-deficit/hyperactivity disorder (ADHD), that is prevalent in approximately 3%–5% of children,[1,2] has been found to be a common precursor of psychotic disorders in medical register studies[3–5] as well as in retrospective[6–9] and prospective studies.[10,11] A recent study found childhood ADHD not only to be more frequent in patients with a first-episode psychosis than in the general population but also to predict poorer response to treatment.[12] However, the developmental trajectories and mechanisms behind the association between ADHD and psychotic disorders are unknown. Longitudinal designs including mediation analysis can help to shed light on them.

Consistent with traditional developmental models of psychosis,[13] our conceptualization is that ADHD represents a risk indicator in the premorbid phase of psychosis that is associated with an increased likelihood of psychotic experiences in the prodrome that in turn precede the full-blown disorder. Despite promising interventions to prevent the "late" transition from the prodrome to the disorder, their outcomes to date are limited and there still is a substantial amount of transition to psychosis.[14,15] Therefore, the "early" transition from the premorbid phase to the prodrome is a worthy target of examination.[16,17]

One possible mediator between ADHD and psychotic experiences is childhood trauma. Children with ADHD are inattentive, impulsive, and have a tendency towards risk and sensation seeking with the consequence that they are more prone to accidents[18,19] and to being injured than the general population.[20] In a representative study, adults diagnosed with ADHD in childhood retrospectively reported more physical and sexual abuse than adults without ADHD.[21] Similarly, posttraumatic stress disorder was more common in adolescents with ADHD than in adolescents without the disorder.[22] Childhood trauma is also a common experience in individuals with psychotic disorders.[23–25] According to the traumagenic neurodevelopmental model of psychosis, traumatic experiences disturb stress regulation mechanisms and establish an enduring oversensitivity to stress which renders people vulnerable to future psychosis.[26,27] Putting the pieces together, ADHD may increase the risk of traumatic experiences in childhood which in turn increases the likelihood of psychotic experiences.

Another possible mediator between ADHD and psychotic experiences is bullying. Compared to their nonaffected peers, children and adolescents with ADHD are more likely to be bullied as well as to bully others.[28,29] Factors that contribute to being bullied by peers are being different in some way and having poor relationships with teachers and peers.[30] Studies find that children with ADHD are less liked and more often rejected by peers, have fewer close friends, and are more likely to have friends who exhibit deviant behavior.[31,32] Having been a victim of bullying in childhood is also frequent in people with psychotic disorders.[33,34] Consequences of bulling have been found in emerging psychotic experiences and symptoms, not only in pure victims but also in those who are both victims and perpetrators (bully/victims) and in pure bullies.[35–37] Summing up, children with ADHD are more likely to be involved in bullying compared to children without ADHD and children who are involved in bullying are more likely to have psychotic experiences in adolescence.

To conclude, there is evidence that ADHD is associated with trauma and bullying and that trauma and bullying are associated with psychotic experiences. However, so far, no study has tested whether trauma and bullying explain the association between ADHD and psychosis that has been found in previous research. In a prior study on data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we found the combined subtype of ADHD assessed at age 7 to be strongly associated with psychotic experiences at age 12 even when potential confounders and the occurrence of other disorders were controlled for (OR 3.35, 95% CI 1.59–7.07; Hennig et al[38]). Moreover, although the full range of possible childhood disorders was assessed, the only other comparably frequent childhood disorder significantly associated with psychotic experiences at age 12 after controlling for other disorders was specific phobia.

In the present study, we further investigated the connection between ADHD combined subtype and psychotic experiences by testing whether it is, at least partially, mediated by traumatic experiences or involvement in bullying. As there is evidence that all childhood disorders are associated with an increased risk for psychotic disorders,[5] we repeated the analyses with specific phobia to investigate whether the mediation is specific to ADHD or represents a general feature of childhood psychopathology.

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