Marcelo Schmitz

ADHD in a school sample of Brazilian adolescents : A study of prevalence, comorbid conditions, and impairments

OBJECTIVE To evaluate the prevalence, comorbid conditions, and impairments of attention-deficit/hyperactivity disorder (ADHD) among young adolescents in Porto Alegre, Brazil. METHOD 1,013 students aged 12 to 14 years were evaluated at 64 state schools, using a screening instrument based on the 18 DSM-IV ADHD symptoms. All positive screened students (n = 99) and a random subset of negative screened subjects (n = 92) had a psychiatric evaluation carried out within a hospital setting or at home. RESULTS The prevalence of ADHD was estimated to be 5.8% (95% confidence interval = 3.2-10.6), and the comorbidity with other disruptive behavior disorders was high (47.8%). Youths with ADHD (n = 23) had significantly higher rates of school repetitions, suspensions, and expulsions (p < .01) than controls (n = 168). No association was identified between ADHD and alcohol, marijuana, and inhalant use. CONCLUSION The results extend to adolescents well-documented findings in children, indicating that ADHD is quite prevalent in early adolescence and affected youths are at high risk for impairment and dysfunction in multiple domains.

Attention-Deficit/Hyperactivity Disorder in a Diverse Culture: Do Research and Clinical Findings Support the Notion of a Cultural Construct for the Disorder?

There is still some debate in the literature whether Attention-Deficit Disorder/Hyperactivity (ADHD) is best conceptualized as a biological disorder or if it is best understood as a cultural construct. This review aims to contribute to disentangle this issue assessing clinical and research data on ADHD in a complete diverse culture from a developing country. We performed a systematic computerized review of the literature on ADHD in Brazil. All investigations were included if dealing with ADHD prevalence, etiology, symptomatological construct, or treatment. Findings were compared to those from studies in developed countries. The prevalence rates of ADHD (5.8% using DSM-IV criteria, 1.5% using ICD-10), the bi-dimensional factor construct extracted from factor analyses (inattention and hyperactivity/impulsivity), the pattern of ADHD comorbidity in clinical samples, the family genetic data suggesting a 39% family transmission in clinical samples and the role of some potential candidate genes in dopaminergic and noradrenergic systems, as well as data on the efficacy of methylphenidate in the disorder are all very similar to findings from developed countries. Taken together, these findings suggest that ADHD is not a cultural construct, reinforcing the importance of applying similar research methodology in different cultures to make findings comparable.

Neuropsychological Performance in DSM-IV ADHD Subtypes: An Exploratory Study with Untreated Adolescents

Objective: To explore neuropsychological performance in untreated Brazilian adolescents suffering from attention-deficit hyperactivity disorder (ADHD). Method: We assessed 30 untreated adolescents with ADHD and 60 healthy control subjects, aged 12 to 16 years, using a neuropsychological battery including the Wisconsin Card-Sorting Test (WCST), the Stroop Test (ST), the Digit Span, and the Word Span. Results: We found neuropsychological differences among the DSM-IV ADHD subtypes. Adolescents with the predominantly inattentive subtype (ADHD-I) performed more poorly than did control subjects on both the Digit Span and the ST. On both the Digit Span and the WCST, adolescents with the combined subtype (ADHD-C) presented significantly more impairments than did control subjects. Adolescents with the predominantly hyperactive-impulsive type (ADHD-HI) did not differ significantly from the control subjects in any measure assessed, but had a better performance than did those with ADHD-C on both the Digit Span and the WCST. In addition, adolescents with ADHD-HI performed better on the ST than did adolescents with ADHD-I. Conclusions: These findings suggest cognitive differences among ADHD subtypes, supporting the diagnostic distinction among them. Adolescents with ADHD-HI do not seem to have significant cognitive deficits.

Smoking during Pregnancy and Attention-Deficit/Hyperactivity Disorder, Predominantly Inattentive Type: A Case-Control Study.

OBJECTIVE Few previous studies assessed specifically attention-deficit/hyperactivity disorder, predominantly inattentive subtype (ADHD-I) in nonreferred samples. This study investigated the association between ADHD-I and prenatal exposure to nicotine. METHOD In a case-control study performed between September 2002 and April 2005, we assessed a nonreferred Brazilian sample of 100 children and adolescents with ADHD-I and 100 non-ADHD controls (6-18 years old). Cases and controls, matched by gender and age, were screened using teacher reports in the Swanson, Nolan, and Pelham-IV (SNAP-IV) scale. They were systematically evaluated through structured diagnostic interviews. Prenatal exposure to nicotine and potential confounding factors were evaluated by direct interview with mothers. RESULTS Adjusting for confounding factors (maternal ADHD, oppositional defiant disorder, birth weight, and alcohol use during pregnancy), children whose mothers smoked>or=10 cigarettes per day during pregnancy presented a significantly higher odds ratio for ADHD-I than children who were not exposed to nicotine during pregnancy (odds ratio 3.44; 95% confidence interval 1.17-10.06). Dimensional analyses showed significantly higher inattentive scores in subjects whose mothers smoked>or=10 cigarettes per day than in others after adjusting for confounding factors (p=.002). CONCLUSIONS In a nonreferred sample, the authors expanded to ADHD-I previous findings documenting the association between prenatal exposure to nicotine and broadly defined ADHD in clinical samples.

Is the α-2A adrenergic receptor gene (ADRA2A) associated with attention-deficit/hyperactivity disorder?

Attention‐Deficit/Hyperactivity Disorder (ADHD) is a complex childhood‐onset psychiatric disorder characterized by marked symptoms of inattention, hyperactivity, and impulsivity. The role of genetic factors in its etiology is strongly supported by family, adoption, and twin studies. Although most of the molecular studies have investigated the dopamine D4 receptor gene (DRD4) and the dopamine transporter gene (DAT1) genes in its etiology, pharmacological and brain imaging evidences seem to indicate that genes of the adrenergic system could also be attractive for association studies. We investigated a sample of 96 Brazilian ADHD children and adolescents and their parents for the ADRA2A MspI polymorphism. Although no association with either MspI allele was observed through the haplotype relative risk (HRR) analysis, effects of the ADRA2A gene on inattention and combined (inattention + hyperactivity/impulsivity) symptom scores were detected (U = 222.5, z = 2.19, P = 0.03; and U = 208.5, z = 2.32, P = 0.02, respectively). Our results suggest that the ADRA2A gene might have a small effect on ADHD susceptibility or that this gene might modulate the severity of the disorder. They are also consistent with the noradrenergic theories of ADHD, suggesting a role for the α2A adrenergic receptors in the disorder.

Association between alpha-2a-adrenergic receptor gene and ADHD inattentive type.

BACKGROUND Previous investigations have demonstrated that an MspI polymorphism at the adrenergic alpha2A receptor gene (ADRA2A) is associated with severity of attention-deficit/hyperactivity disorder (ADHD) inattentive symptoms in clinical samples composed mainly of subjects with ADHD, combined type. This study aimed to investigate the association between this ADRA2A polymorphism and attention-deficit/hyperactivity disorder-inattentive type (ADHD-I) in a nonreferred sample. METHODS In a case-control study, we assessed a sample of 100 children and adolescents with ADHD-I and 100 non-ADHD controls. Cases and controls were matched by gender and age and were screened by using teacher reports in a revised version of the Swanson, Nolan, and Pelham rating scale at 12 schools. Psychiatric diagnoses were derived through structured diagnostic interviews. RESULTS Homozygous subjects for the G allele at the ADRA2A had significantly higher odds ratio (OR) for ADHD-I than did those with other genotypes (CC + CG genotypes), even after adjusting for potential confounders (p = .02; OR = 3.78; 95% confidence interval = 1.23-11.62). In family-based analyses, no significant associations were detected. CONCLUSIONS Our results suggest that the ADRA2A may be associated with ADHD-I, replicating previous findings from clinical samples that have suggested the importance of this gene for the dimension of inattention. In addition, these results support the role of the noradrenergic system in ADHD.

Exploring ADHD age-of-onset criterion in Brazilian adolescents.

Abstract Objective: To explore age-of-onset criterion for the diagnosis of attention–deficit hyperactivity disorder (ADHD) in a school sample of young Brazilian adolescents. Methods: 191 students aged 12 to 14 years were evaluated using DSM-IV ADHD criteria, measures of ADHD symptoms and global impairment. Results: Both adolescents with ADHD (n=30) and adolescents who fulfilled all DSM-IV ADHD criteria, except age of onset of impairment criterion (ADHD w/o age-of-onset, n=27) had significantly higher scores on Attention Problems, Delinquent and Aggressive Behavior scales of the Child Behavior Checklist (CBCL) and lower scores on the Child Global Assessment scale (CGAS) than non-ADHD adolescents (n=134). Adolescents with ADHD and youths with ADHD w/o age-of-onset did not differ significantly in any measure assessed. Conclusion: These results concur with recent literature proposing revision of the age-of-onset criterion for the diagnosis of ADHD.

Juvenile bipolar disorder in Brazil: clinical and treatment findings.

BACKGROUND Because few studies were conducted to evaluate bipolar disorder in children and adolescents outside North America, this investigation aims to describe clinical features, pattern of comorbidities, and response to pharmacologic treatment in a sample of youths with bipolar disorder (BD) from a pediatric psychopharmacology outpatient clinic in Brazil. METHODS We performed a retrospective chart review of all patients under age 15 with BD diagnoses who were evaluated and treated in our clinic from 1998-2001. A comparison sample of subjects with attention-deficit/hyperactivity disorder (ADHD) without BD (n = 362) was also evaluated. RESULTS The prevalence of juvenile BD in our sample was 7.2% (36/500) (95% confidence interval = 5.2-9.9). Irritable mood was detected in 91.7% of the bipolar patients. The main comorbidity found was ADHD (58.3%). Children with BD had significantly higher rates of abnormally elevated CBCL scores in the externalizing dimension, anxiety and depression, delinquent behavior, and aggressive behavior scales than ADHD subjects (p <.05). Most BD patients (78%) needed combination drug therapy to achieve symptomatic control. CONCLUSIONS Our results replicate clinical and treatment findings from U.S. investigations in a different culture demonstrating that juvenile BD is not a rare disorder in clinical samples.

Adrenergic α2A receptor gene and response to methylphenidate in attention-deficit/hyperactivity disorder-predominantly inattentive type

SummaryAn association between ADRA2A −1291 C > G polymorphism and response to methylphenidate in inattentive symptoms was previously suggested in children with ADHD. No investigation specifically assessed this association in ADHD–inattentive type (ADHD-I). In this naturalistic pharmacogenetic study, 59 subjects with ADHD-I from a non-referred sample were treated with short-acting methylphenidate and genotyped for ADRA2A −1291 C > G polymorphism. The primary outcome measure was the inattentive subscale of the SNAP-IV applied by a child psychiatrist blinded to genotype at baseline and first month of treatment. Children and adolescents with the G allele showed significantly lower inattentive scores with MPH treatment at the first month of treatment than subjects without the G allele (n = 59; F = 6.14; p = 0.016). We extended to ADHD-I previous findings suggesting the influence of the G allele at the ADRA2A −1291 C > G polymorphism on the improvement of inattentive symptoms with methylphenidate in children with all ADHD subtypes.

Food intake and serum levels of iron in children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE To investigate hematologic variables related to iron deficiency and food intake in attention-deficit/hyperactivity disorder. METHOD The sample comprised 62 children and adolescents (6-15 years old) divided into three groups: Group 1: 19 (30.6%) patients with attention-deficit/hyperactivity disorder using methylphenidate for 3 months; Group 2: 22 (35.5%) patients with attention-deficit/hyperactivity disorder who were methylphenidate naive and Group 3: 21 (33.9%) patients without attention-deficit/hyperactivity disorder. Serum iron, ferritin, transferrin, hemoglobin, mean corpuscular volume, red cell distribution width, mean corpuscular hemoglobin concentration, nutritional diagnostic parameters - Body Mass Index Coefficient, food surveys were evaluated among the groups. RESULTS The attention-deficit/hyperactivity disorder group drug naive for methylphenidate presented the highest red cell distribution width among the three groups (p = 0.03). For all other hematologic and food survey variables, no significant differences were found among the groups. No significant correlation between dimensional measures of attention-deficit/hyperactivity disorder symptoms and ferritin levels was found in any of the three groups. CONCLUSION Peripheral markers of iron status and food intake of iron do not seem to be modified in children with attention-deficit/hyperactivity disorder, but further studies assessing brain iron levels are needed to fully understand the role of iron in attention-deficit/hyperactivity disorder pathophysiology.