Neuropsychological factors differentiating treated children with pediatric bipolar disorder from those with attention-deficit/hyperactivity disorder

Are patients with bipolar disorder and comorbid attention-deficit hyperactivity disorder more neurocognitively impaired?

OBJECTIVE

Research on neurocognitive impairment in adult patients with comorbid bipolar disorder (BD) and attention-deficit hyperactivity disorder (ADHD) is very scarce. This study assessed the neurocognitive profile of a comorbid group (BD+ADHD) compared with that of pure BD (pBD) group, pure ADHD (pADHD) group and healthy controls (HCs).

METHODS

This was a three-site study comprising 229 subjects: 70 patients with pBD, 23 with BD+ADHD, 50 with pADHD, and 86 HCs. All patients with BD had been euthymic for at least 6 months. Neuropsychological performance was assessed using a comprehensive neurocognitive battery.

RESULTS

Our results showed that all the clinical groups had poorer performance than the HCs in all the neurocognitive domains except for executive functions. No significant differences were observed between the pBD and BD+ADHD groups in any of the cognitive domains, with these two groups showing greater impairment than the pADHD group in executive functions and visual memory.

CONCLUSIONS

Our results, although preliminary, suggest that the BD+ADHD group showed the same neurocognitive profile as pBD patients, most likely reflecting the same neurobiological basis. On the other hand, the pADHD group showed a more selective moderate impairment in attention.

Response inhibition in the parametric go/no-go task and its relation to impulsivity and subclinical psychopathy

The current study utilizes the parametric go/no-go task (PGNG), a task that examines changes in inhibitory performance as executive function load increases, to examine the link between psychopathic traits, impulsivity, and response inhibition in a cohort of healthy participants. The results show that as executive function load increased, inhibitory ability decreased. High scores on the Cognitive Complexity subscale of the Barratt Impulsivity Scale (BIS-11) predict poor inhibitory ability in the PGNG. Similarly, high scores on the Psychopathy Personality Inventory-Revised (PPI-R) Blame Externalization subscale predict response inhibition deficits in the PGNG, which loads more on the executive functions than the standard go/no-go task. The remaining BIS-11 as well as PPI-R subscales did not interact with inhibitory performance in the PGNG highlighting the specificity of associations between aspects of personality and impulsivity with inhibitory performance as cognitive load is increased. These data point towards the sensitivity of the PGNG in studying response inhibition in the context of highly impulsive populations and its utility as a measure of impulsivity.

Comorbidity in pediatric bipolar disorder: prevalence, clinical impact, etiology and treatment

BACKGROUND

Research on pediatric bipolar disorder (PBD) is providing a plethora of empirical findings regarding its comorbidity. We addressed this question through a systematic review concerning the prevalence, clinical impact, etiology and treatment of main comorbid disorders involved.

METHOD

A comprehensive database search was performed from 1990 to August 2014. Overall, 167 studies fulfilled the inclusion criteria.

RESULTS

Bipolar youth tend to suffer from comorbid disorders, with highest weighted mean prevalence rate arising from anxiety disorders (54%), followed by attention deficit hyperactivity disorder (ADHD) (48%), disruptive behavior disorders (31%), and substance use disorders (SUD) (31%). Furthermore, evidence indicates that ADHD and anxiety disorders negatively affect the symptomatology, neurocognitive profile, clinical course and the global functioning of PBD. Likewise, several theories have been posited to explain comorbidity rates in PBD, specifically common risk factors, one disorder being a risk factor for the other and nosological artefacts. Lastly, randomized controlled trials highlight a stronger therapeutic response to stimulants and atomoxetine (vs. placebo) as adjunctive interventions for comorbid ADHD symptoms. In addition, research focused on the treatment of other comorbid disorders postulates some benefits from mood stabilizers and/or SGA.

LIMITATIONS

Epidemiologic follow-up studies are needed to avoid the risk of nosological artefacts. Likewise, more research is needed on pervasive developmental disorders and anxiety disorders, especially regarding their etiology and treatment.

CONCLUSIONS

Psychiatric comorbidity is highly prevalent and is associated with a deleterious clinical effect on pediatric bipolarity. Different etiological pathways may explain the presence of these comorbid disorders among bipolar youth. Standardized treatments are providing ongoing data regarding their effectiveness for these comorbidities among bipolar youth.

Attention-based classification pattern, a research domain criteria framework, in youths with bipolar disorder and attention-deficit/hyperactivity disorder

OBJECTIVE

The National Institute of Mental Health has initiated the Research Domain Criteria (RDoC) project. Instead of using disorder categories as the basis for grouping individuals, the RDoC suggests finding relevant dimensions that can cut across traditional disorders. Our aim was to use the RDoC's framework to study patterns of attention deficit based on results of Conners' Continuous Performance Test (CPT II) in youths diagnosed with bipolar disorder (BD), attention-deficit/hyperactivity disorder (ADHD), BD+ADHD and controls.

METHOD

Eighteen healthy controls, 23 patients with ADHD, 10 with BD and 33 BD+ADHD aged 12-17 years old were assessed. Pattern recognition was used to partition subjects into clusters based simultaneously on their performance in all CPT II variables. A Fisher's linear discriminant analysis was used to build a classifier.

RESULTS

Using cluster analysis, the entire sample set was best clustered into two new groups, A and B, independently of the original diagnoses. ADHD and BD+ADHD were divided almost 50% in each subgroup, and there was an agglomeration of controls and BD in group B. Group A presented a greater impairment with higher means in all CPT II variables and lower Children's Global Assessment Scale. We found a high cross-validated classification accuracy for groups A and B: 95.2%. Variability of response time was the strongest CPT II measure in the discriminative pattern between groups A and B.

CONCLUSION

Our classificatory exercise supports the concept behind new approaches, such as the RDoC framework, for child and adolescent psychiatry. Our approach was able to define clinical subgroups that could be used in future pathophysiological and treatment studies.

Distinguishing bipolar disorder from other psychiatric disorders in children

Pediatric onset bipolar disorder (BD) is a challenging diagnosis with potentially debilitating outcomes. This review aims to critically evaluate recently published literature relevant to the diagnosis of BD in youth, emphasizing interesting and important new findings characterizing pediatric BD and reporting updates in the diagnostic and statistical manual relevant to this disorder in youth. Challenges regarding the diagnosis of BD will be discussed, in addition to important distinctions with other childhood disorders, including other bipolar spectrum disorders; major depressive disorder; dysthymia; disruptive mood dysregulation disorder (DMDD); attention-deficit/hyperactivity disorder (ADHD) and other disruptive behavioral disorders; anxiety disorders, including post-traumatic stress disorder (PTSD); psychotic disorders; autism spectrum disorders; substance use disorders; and borderline personality disorder. The review concludes with a comment on past research limitations and future directions in the field.

Neurocognitive impairments among youth with pediatric bipolar disorder: a systematic review of neuropsychological research

BACKGROUND

Pediatric bipolar disorder (PBD) has emerged as a field of research in which neuropsychological studies are continuously providing new empirical findings. Despite this, a comprehensive framework for neurocognitive impairments is still lacking, and most of the evidence remains unconnected. We addressed this question through a systematic review of neuropsychological research, with the aim of elucidating the main issues concerning this topic.

METHOD

A comprehensive search of databases (PubMed, PsycINFO) was performed. Published manuscripts between 1990 and January 2014 were identified. Overall, 124 studies fulfilled inclusion criteria. Methodological differences between studies required a descriptive review of findings.

RESULTS

Evidence indicates that verbal/visual-spatial memory, processing speed, working memory, and social cognition are neurocognitive domains impaired in PBD youth. Furthermore, these deficits are greater among those who suffer acute affective symptoms, PBD type I, and/or attention deficit hyperactivity disorder (ADHD) comorbidity. In addition, several neurocognitive deficits imply certain changes in prefrontal cortex activity and are somewhat associated with psychosocial and academic disabilities. Strikingly, these deficits are consistently similar to those encountered in ADHD as well as severe mood dysregulation (SMD). Besides, some neurocognitive impairments appear before the onset of the illness and tend to maintain stable across adolescence. Finally, any therapy has not yet demonstrated to be effective on diminishing these neurocognitive impairments.

LIMITATIONS

More prolonged follow-up studies aimed at delineating the course of treatment and the response to it are warranted.

CONCLUSIONS

Despite noteworthy research on the neurocognitive profile of PBD, our knowledge is still lagging behind evidence from adult counterparts.

Bipolar disorder in children: assessment in general pediatric practice

PURPOSE OF REVIEW

Pediatricians are increasingly confronted with the mental health needs of children. Given the unanticipated role, well-described diagnostic guidelines and treatment protocols are essential: but often lacking. Identification of bipolar disorder in children, a condition which lacks diagnostic criteria consensus, presents a particular challenge. Despite this, it is generally regarded as a condition associated with considerable morbidity and mortality. Extended delays to treatment, typical for the condition, contribute to significantly reduced adult functionality.

RECENT FINDINGS

Most children with bipolar disorder exhibit a subsyndromal course of illness. This has prompted many investigative groups to explore whether such a presentation is developmental or unique. Despite the ongoing debate, there has been a rapid increase in the rate of diagnoses. Concurrently, breakthroughs in neurology, neuroimaging, and genetics have called into question the existing conceptually based psychiatric constructs altogether. New research approaches which reflect these advances are more likely to lead to evidence-based diagnosis and treatment. Such an example is a novel phenotype called Fear of Harm (FOH). A new research perspective resulted in the unification of a broad range of symptoms from bipolar disorder as well as many of the co-occurring disorders. When considered as a whole, the syndrome maps on to a known neural pathway and has led investigators to a putative biomarker.

SUMMARY

If given the right information and tools, pediatricians are uniquely positioned to interrupt the decline caused by mental illnesses. Importantly, the newly defined FOH syndrome includes clinical symptoms which are frequently first brought to the attention of pediatricians. Although these symptoms are not exclusive to the mood disorder, they could alert pediatricians to the need for further evaluation.

Genetic and neurocognitive foundations of emotion abnormalities in bipolar disorder

INTRODUCTION

Bipolar Disorder (BD) is a serious mood disorder, the aetiology of which is still unclear. The disorder is characterised by extreme mood variability in which patients fluctuate between markedly euphoric, irritable, and elevated states to periods of severe depression. The current research literature shows that BD patients demonstrate compromised neurocognitive ability in addition to these mood symptoms. Viable candidate genes implicated in neurocognitive and socioemotional processes may explain the development of these core emotion abnormalities. Additionally, links between faulty neurocognition and impaired socioemotional ability complement genetic explanations of BD pathogenesis. This review examines associations between cognition indexing prefrontal neural regions and socioemotional impairments including emotion processing and regulation. A review of the effect of COMT and TPH2 on these functions is also explored.

METHODS

Major computer databases including PsycINFO, Google Scholar, and Medline were consulted in order to conduct a comprehensive review of the genetic and cognitive literature in BD.

RESULTS

This review determines that COMT and TPH2 genetic variants contribute susceptibility to abnormal prefrontal neurocognitive function which oversees the processing and regulation of emotion. This provides for greater understanding of some of the emotional and cognitive symptoms in BD.

CONCLUSIONS

Current findings in this direction show promise, although the literature is still in its infancy and further empirical research is required to investigate these links explicitly.

An update on the debated association between ADHD and bipolar disorder across the lifespan

Diagnostic formulations for attention deficit hyperactivity disorder (ADHD) and bipolar disorder (BD) both include symptoms of distractibility, psychomotor agitation and talkativeness, alongside associated emotional features (irritability and emotional lability). Treatment studies suggest the importance of accurate delineation of ADHD and BD. However, boundaries between the two disorders are blurred by the introduction of broader conceptualisations of BD. This review attempts to elucidate whether associations between ADHD and BD are likely to be driven by superficial symptomatological similarities or by a more meaningful etiological relationship between the disorders. This is achieved by outlining findings on comorbidity, temporal progression of the disorders, familial co-variation, and neurobiology in ADHD and BD across the lifespan. Longitudinal studies fail to consistently show developmental trajectories between ADHD and BD. Comparative research investigating neurobiology is in its infancy, and although some similarities are seen between ADHD and BD, studies also emphasise differences between the two disorders. However, comorbidity and family studies appear to show that the two disorders occur together and aggregate in families at higher than expected rates. Furthermore close inspection of results from population studies reveals heightened co-occurrence of ADHD and BD even in the context of high comorbidity commonly noted in psychopathology. These results point towards a meaningful association between ADHD and BD, going beyond symptomatic similarities. However, future research needs to account for heterogeneity of BD, making clear distinctions between classical episodic forms of BD, and broader conceptualisations of the disorder characterised by irritability and emotional lability, when evaluating the relationship with ADHD.