ADHD in adults--a familiar disease with unfamiliar challenges

Shared alterations in resting-state brain connectivity in adults with attention-deficit/hyperactivity disorder and their unaffected first-degree relatives

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a developmental condition that often persists into adulthood with extensive negative consequences on quality of life. Despite emerging evidence indicating the genetic basis of ADHD, investigations into the familial expression of latent neurocognitive traits remain limited.

METHODS

In a group of adult ADHD probands (n = 20), their unaffected first-degree relatives (n = 20) and typically developing control participants (n = 20), we assessed endophenotypic alterations in the default mode network (DMN) connectivity during resting-state functional magnetic resonance imaging in relation to cognitive performance and clinical symptoms. In an external validation step, we also examined the dimensional nature of this neurocognitive trait in a sample of unrelated healthy young adults (n = 100) from the Human Connectome Project (HCP).

RESULTS

The results illustrated reduced anti-correlations between the posterior cingulate cortex/precuneus and right middle frontal gyrus that was shared between adult ADHD probands and their first-degree relatives, but not with healthy controls. The observed connectivity alterations were linked to higher ADHD symptoms that was mediated by performance in a sustained attention task. Moreover, this brain-based neurocognitive trait dimensionally explained ADHD symptom variability in the HCP sample.

CONCLUSIONS

Alterations in the default mode connectivity may represent a dimensional endophenotype of ADHD, hence a significant aspect of the neuropathophysiology of this disorder. As such, brain network organisation can potentially be employed as an important neurocognitive trait to enhance statistical power of genetic studies in ADHD and as a surrogate efficacy endpoint in the development of novel pharmaceuticals.

Evaluation of Risk Factors for ADHD and Co-Morbid Psychiatric Disorders Among the Parents of Children With ADHD

OBJECTIVE

The aim of this study is to investigate the presence of ADHD and other psychiatric disorders among parents with at least one child with ADHD relative to parents with children who do not have ADHD.

METHOD

Eighty five parents of children with ADHD with 68 control parents who had healthy children without ADHD were interviewed for participation in present study. Each parent was evaluated for co-existing psychiatric disorders using the Structured Clinical Interview for the DSM IV Axis I Disorders (SCID I).

RESULTS

We found that ADHD and co-morbid psychiatric symptoms were increased in the parents of children with ADHD in comparison with the healthy control group.

CONCLUSION

Psychiatric co-morbidity was more common among the parents of patients with inattentive and combined presentations. Adult ADHD is associated with psychiatric co-morbidities including anxiety disorders, mood disorders, and somatoform disorders as well as substantial role impairment.

Temporal reproduction and its neuroanatomical correlates in adults with attention deficit hyperactivity disorder and their unaffected first-degree relatives

BACKGROUND

Little is known about time perception, its putative role as cognitive endophenotype, and its neuroanatomical underpinnings in adults with attention deficit hyperactivity disorder (ADHD).

METHOD

Twenty adults with ADHD, 20 unaffected first-degree relatives and 20 typically developing controls matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional grey-matter volumes. Temporal processing was investigated as a putative cognitive endophenotype using a temporal reproduction paradigm. General linear modelling was employed to examine the relationship between temporal reproduction performances and grey-matter volumes.

RESULTS

ADHD participants were impaired in temporal reproduction and unaffected first-degree relatives performed in between their ADHD probands and typically developing controls. Increased grey-matter volume in the cerebellum was associated with poorer temporal reproduction performance.

CONCLUSIONS

Adults with ADHD are impaired in time reproduction. Performances of the unaffected first-degree relatives are in between ADHD relatives and controls, suggesting that time reproduction might be a cognitive endophenotype for adult ADHD. The cerebellum is involved in time reproduction and might play a role in driving time performances.

Neuroanatomical abnormalities and cognitive impairments are shared by adults with attention-deficit/hyperactivity disorder and their unaffected first-degree relatives

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder, yet the search for genes with a definitive role in its etiology has been elusive. Deconstructing the disorder in its endophenotypic traits, where the variance is thought to be associated with a fewer number of genes, should boost the statistical power of molecular genetic studies and clarify the pathophysiology of ADHD. In this study, we tested for neuroanatomical and cognitive endophenotypes in a group of adults with ADHD, their unaffected first-degree relatives, and typically developing control subjects.

METHODS

Sixty participants, comprising 20 adults with ADHD, 20 unaffected first-degree relatives, and 20 typically developing control subjects matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional gray and white matter volumes. General linear analyses of the volumes of brain regions, adjusting for age and total intracranial volume, were used to compare groups. Sustained attention and response inhibition were also investigated as cognitive endophenotypes.

RESULTS

Neuroanatomical abnormalities in gray matter volume in the right inferior frontal gyrus and white matter volume in the caudal portion of the right inferior fronto-occipital fasciculus were shared between ADHD probands and their unaffected first-degree relatives. In addition, impairments in sustained attention were also found to be shared between ADHD patients and their relatives.

CONCLUSIONS

Cognitive impairments in sustained attention and neuroanatomical abnormalities in the right inferior frontal gyrus and the posterior part of right inferior fronto-occipital fasciculus are putative neurocognitive endophenotypes in adult ADHD.

Attention-deficit/hyperactivity disorder in adults with bipolar disorder or major depressive disorder: results from the international mood disorders collaborative project

OBJECTIVE

Relatively few studies have evaluated the clinical implications of lifetime attention-deficit/hyperactivity disorder (ADHD) in adults with bipolar disorder or major depressive disorder (MDD). Herein, we sought to determine the prevalence as well as the demographic and clinical correlates of lifetime ADHD in persons with a mood disorder.

METHOD

The first 399 patients enrolled in the International Mood Disorders Collaborative Project (IMDCP) were evaluated for lifetime ADHD using the Mini-International Neuropsychiatric Interview-Plus (MINI-Plus) as the primary instrument to derive current and lifetime DSM-IV diagnoses. All analyses of variables of interest were conducted utilizing the MINI-Plus, the Adult ADHD Self-Report Scale-v1.1, and the Wender Utah Rating Scale-Short Form. The effect of ADHD on clinical presentation, course of illness variables, comorbidity, anamnesis, treatment, and outcome are reported. The IMDCP is a joint initiative of the Mood Disorders Psychopharmacology Unit at the University Health Network, University of Toronto, Toronto, Ontario, Canada, and the Cleveland Clinic Center for Mood Disorders Treatment and Research at Lutheran Hospital, Cleveland, Ohio. All data for this study were procured between January 2008 and January 2009.

RESULTS

The percentages of subjects with MDD or bipolar disorder meeting the DSM-IV criteria for lifetime adult ADHD were 5.4% and 17.6% (P < .001), respectively. Lifetime comorbid ADHD in both mood disorder populations was associated with earlier age at illness onset (MDD, P = .049; bipolar disorder, P = .005), a higher number of psychiatric comorbidities (eg, MDD and current panic disorder with agoraphobia [P = .002]; bipolar disorder and social phobia [P = .012]), and decreased quality of life (MDD, P = .018).

CONCLUSIONS

The overarching findings herein are that the adult ADHD phenotype is commonly reported by individuals with MDD or bipolar disorder and is associated with a greater illness burden and complexity.

Bipolar disorder and ADHD: Clinical concerns

During the past decade, a similar composite has emerged for both bipolar disorder and adult attention-deficit/hyperactive disorder (ADHD). First, both conditions have a relatively high prevalence, a low case detection, a protracted illness course, a high rate of comorbidity, multifactorial ideology, substantial heritable liability, and tremendous burden of illness in economic cost as well as interpersonal and vocational maladjustments. What has also been interesting along with these reports is that there has been emerging scientific studies implicating common brain regions and neural circuits subserving essential features of both conditions.

Once-daily atomoxetine for adult attention-deficit/hyperactivity disorder: a 6-month, double-blind trial

This randomized, double-blind, placebo-controlled, 6-month trial examined the efficacy and safety of once-daily morning-dosed atomoxetine in adult patients with attention-deficit/hyperactivity disorder (ADHD) and the efficacy of atomoxetine in ameliorating symptoms through the evening hours. Patients received once-daily atomoxetine (n = 250) or placebo (n = 251) in the morning for approximately 6 months. The efficacy measures included the Adult ADHD Investigator Symptom Rating Scale (AISRS), Conners' Adult ADHD Rating Scale-Investigator Rated: Screening Version, Clinical Global Impressions-ADHD-Severity of Illness, and Adult ADHD Quality of Life Scale. Overall, 94 patients randomized to atomoxetine and 112 patients randomized to placebo completed the study. On the AISRS total score, Conners' Adult ADHD Rating Scale-Investigator Rated: Screening Version evening index total score, Clinical Global Impressions-ADHD-Severity of Illness score, and Adult ADHD Quality of Life Scale total score, atomoxetine was statistically superior to placebo at the 10-week and 6-month time points. From the visitwise analysis, the mean (SD) AISRS total scores for atomoxetine decreased from 38.2 (7.5) at baseline to 21.4 (12.3) at the 6-month end point compared with 38.6 (7.0) to 25.8 (13.2) for placebo (P = 0.035). Nausea, dry mouth, fatigue, decreased appetite, urinary hesitation, and erectile dysfunction were the treatment-emergent adverse events reported significantly more often with atomoxetine. Discontinuations due to adverse events were 17.2% and 5.6% for atomoxetine and placebo, respectively (P < 0.001). Once-daily morning-dosed atomoxetine is efficacious for treating ADHD in adults when measured 10 weeks and 6 months after initiating treatment. Atomoxetine demonstrated significant efficacy that continued into the evening. Adverse events were similar to previous trials.