Claudia Maciel Szobot

Alcohol use among adolescents: concepts, epidemiological characteristics and etiopatogenic factors

Alcohol is the most consumed substance among young people, and the onset of its use is starting at an earlier age, raising the risks of future dependence. The use of alcohol in adolescence is associated with a series of risk behaviors, besides raising the risk of involvement in accidents, sexual violence, and participating in gangs. Alcohol use by adolescents is strongly associated with violent death, poor academic performance, learning difficulties and damage in the development and structuring of cognitive-behavioral and emotional abilities. Alcohol consumption causes neurochemical modifications, with damage in memory, learning and impulse control. Professionals who deal with adolescents must be prepared for a thorough evaluation regarding the possible abusive use or dependence of alcohol in this age group. However, it is important to emphasize that the criteria utilized by some diagnostic tools for abuse and dependence were developed for adults, and must be applied with caution in adolescents. Thus, it is fundamental that these professionals be aware of the characteristics and peculiarities of adolescence and chemical dependence in this age-group.

Dopamine transporter gene and response to methylphenidate in attention-deficit/hyperactivity disorder.

This study aims to evaluate whether a previously reported association between homozygosity for the 10-repeat allele of the dopamine transporter gene (10/10) and poor response to methylphenidate (MPH) would be replicated in a sample of Brazilian attention deficit/hyperactivity disorder (ADHD) boys. In a blind naturalistic study, 50 male ADHD youths were treated with MPH. Efficacy of the medication was measured by means of the 10-item Conners Abbreviated Rating Scale (ABRS), and the Childrens Global Assessment Scale (CGAS). While 75% (15/20) of the youths without 10/10 genotype demonstrated an improvement higher than 50% in the ABRS scores with MPH, only 47% (14/30) of the subjects with 10/10 genotype achieved the same level of improvement with medication (one-tailed P = 0.04). In addition, the group without this genotype had significantly higher increase in the CGAS scores than the other group (one-tailed P < 0.01). Our findings support an association between homozygosity for the 10-repeat allele at dopamine transporter gene locus and poor response to MPH.

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.

Adaptation and construct validation of the Barratt Impulsiveness Scale (BIS 11) to Brazilian Portuguese for use in adolescents

OBJECTIVE Impulsivity is associated with different psychiatric disorders. The Barratt Impulsiveness Scale version 11 is one of the scales mostly used to measure impulsivity and it does not have a validated version for Brazilian Portuguese. The objective of this study is to adapt and conduct the construct validation of the Barratt Impulsiveness Scale version 11 for adolescents. METHOD The scale was translated and adapted into Portuguese and then back-translated into English. The psychometric proprieties, factor analysis and construct validity were evaluated in two samples: 18 bilingual undergraduate medical students and 464 male adolescents between 15 and 20 years old from a well-delimited geographical area in the city of Canoas, southern Brazil. RESULTS The adolescent sample had a mean age of 17.3 +/- 1.7 years. Intra-class correlation coefficient achieved a value of 0.90, and internal consistency had a of 0.62. Factor analysis did not identify the 3 factors of the original scale. Impulsivity scores from the Barratt Impulsiveness Scale version 11 had a correlation with scores for attention deficit/hyperactive disorder and oppositional defiant disorder and with number of symptoms of conduct disorder, suggesting an appropriate construct validity of the scale. CONCLUSION Even considering some limitations in the Portuguese version, Barratt Impulsiveness Scale version 11 can be used in male adolescents and should be tested in other populations.

Impulsivity, age of first alcohol use and substance use disorders among male adolescents: a population based case–control study

AIMS To evaluate the association between impulsivity, age of first alcohol consumption (AFD) and substance use disorders (SUD) in a non-clinical sample of adolescents. DESIGN AND SETTING Population-based case-control study of male adolescents between 15 and 20 years of age nested in a community survey in southern Brazil. PARTICIPANTS Cases were drug or alcohol abusers/dependents defined according to DSM-IV abuse/dependence criteria (n = 63). Individuals who had experienced alcohol use but where non-abusers served as controls (n = 355). Cases and controls completed a structured face-to-face interview. MEASUREMENTS The Mini International Neuropsychiatric Interview (MINI) was completed during the original survey and used to identify cases and controls. Impulsivity was measured by means of the Barratt Impulsivity Scale (BIS 11). Self-reported AFD and socio-demographic data were collected and analyzed through logistic regression according to a hierarchical model. FINDINGS Impulsivity and AFD were significantly associated with SUD. Both higher impulsivity [odds ratio (OR) 3.3, 95% confidence interval (CI) 1.4-7.8] and earlier AFD (OR 1.2, 95% CI 1.0-1.3) remained associated with SUD after model adjustments. CONCLUSIONS The findings from this population-based case-control study suggest that impulsivity and age of first alcoholic drink are associated strongly with alcohol and drug problems. Additionally, impulsivity seems to contribute to a premature exposure to alcohol by hastening the AFD. If the temporal effect of these associations is confirmed in longitudinal designs including broader population groups, our findings may contribute to the development of clinical and policy interventions aiming at reducing the incidence and morbidity associated with substance-related problems among adolescents.

Cognitive impairment in school-aged children with early trauma

Exposure to traumatic events during childhood is often associated with the development of psychiatric disorders, cognitive impairment, and poor functioning in adulthood. However, few studies have examined cognitive function, including executive function, memory, and attention, in school-aged children with early trauma compared with age- and sex-matched controls. We recruited 30 medication-naive children between 5 and 12 years of age with a history of early severe trauma from a foster care home, along with 30 age- and sex-matched controls. Psychiatric diagnoses were based on Kiddie Schedule for Affective Disorders and Schizophrenia Epidemiologic Version (K-SADS-E) for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria and were confirmed with a clinical interview. The neuropsychologic battery was tailored to assess broad cognitive domains such as learning/working memory, executive function, attention, verbal/premorbid intellectual functioning, and impulsivity. There was a higher prevalence of subsyndromal symptoms in children with a history of childhood trauma, although they rarely met all of the diagnostic criteria for a disorder. Moreover, lower estimated intellectual functioning scores were associated with subsyndromal symptoms in children with a history of trauma, and they performed more poorly on the Digits Span Test of the Wechsler Intelligence Scale for Children-III Edition, suggesting attention impairment. There is a high prevalence of subsyndromal symptoms in school-aged children with trauma and an attention impairment, which may contribute to a cumulative deficit early in cognitive development. These findings further support the need for early interventions that can prevent cognitive impairment when childhood trauma occurs.

The acute effect of methylphenidate on cerebral blood flow in boys with attention-deficit/hyperactivity disorder

Methylphenidate (MPH) is the most commonly prescribed treatment for attention-deficit/hyperactivity disorder (ADHD). The therapeutic mechanisms of MPH are not, however, fully understood. We studied the effects of MPH on brain activity in male children and adolescents with ADHD, using the blood flow radiotracer technetium-99m ethyl cysteinate dimer (99mTc-ECD) and single-photon emission tomography (SPET) . The study was randomized, double blind, and placebo controlled (MPH group, n=19; placebo group, n=17), Radiotracer was administered during the performance of the Continuous Performance Test and before and after 4 days of MPH treatment. Statistical parametric mapping (SPM99) analysis showed a significant reduction in regional cerebral blood flow in the left parietal region in the MPH group compared with the placebo group (P<0.05, corrected for multiple comparisons). Our findings suggest that the posterior attentional system, which includes the parietal cortex, may have a role in the mediation of the therapeutic effects of MPH in ADHD.

A randomized crossover clinical study showing that methylphenidate-SODAS improves attention-deficit/hyperactivity disorder symptoms in adolescents with substance use disorder

Our objective was to evaluate the effectiveness of a long-acting formulation of methylphenidate (MPH-SODAS) on attention-deficit/hyperactivity disorder (ADHD) symptoms in an outpatient sample of adolescents with ADHD and substance use disorders (SUD). Secondary goals were to evaluate the tolerability and impact on drug use of MPH-SODAS. This was a 6-week, single-blind, placebo-controlled crossover study assessing efficacy of escalated doses of MPH-SODAS on ADHD symptoms in 16 adolescents with ADHD/SUD. Participants were randomly allocated to either group A (weeks 1-3 on MPH-SODAS, weeks 4-6 on placebo) or group B (reverse order). The primary outcome measures were the Swanson, Nolan and Pelham Scale, version IV (SNAP-IV) and the Clinical Global Impression Scale (CGI). We also evaluated the adverse effects of MPH-SODAS using the Barkley Side Effect Rating Scale and subject reports of drug use during the study. The sample consisted of marijuana (N = 16; 100%) and cocaine users (N = 7; 43.8%). Subjects had a significantly greater reduction in SNAP-IV and CGI scores (P < 0.001 for all analyses) during MPH-SODAS treatment compared to placebo. No significant effects for period or sequence were found in analyses with the SNAP-IV and CGI scales. There was no significant effect on drug use. MPH-SODAS was well tolerated but was associated with more severe appetite reduction than placebo (P < 0.001). MPH-SODAS was more effective than placebo in reducing ADHD symptoms in a non-abstinent outpatient sample of adolescents with comorbid SUD. Randomized clinical trials, with larger samples and SUD intervention, are recommended.

Brain perfusion and dopaminergic genes in boys with attention-deficit/hyperactivity disorder

Neuroimaging studies have suggested the involvement of several brain areas in attention‐deficit/hyperactivity disorder (ADHD). Genetic investigations have supported the role of both dopamine D4 receptor gene (DRD4) and dopamine transporter gene (DAT1) in the vulnerability to the disorder. This study evaluates whether the presence of risk alleles at DRD4 and/or DAT1 genes is associated with differences in regional cerebral blood flow (rCBF) in a sample of ADHD boys. The rCBF was compared between ADHD patients with and without risk alleles at DRD4 (7‐repeat allele) and/or at DAT1 (homozygosis for the 10‐repeat allele) genes by single photon emission computed tomography (SPECT) during continuous performance test. Images were analyzed using statistical parametric mapping (SPM‐99). No significant differences in rCBF were found both between ADHD boys with and without the 7‐repeat allele at DRD4 locus, as well as between ADHD boys homozygous for the 10‐repeat allele and ADHD subjects with other genotypes at the DAT1 locus. However, a significantly higher perfusion in the right middle temporal gyrus was found in the group with risk alleles at both DRD4 and DAT1 loci (n = 6) compared to ADHD boys without risk alleles at both loci (n = 28) (P < 0.05). Our findings suggest that a higher recruitment in middle temporal gyrus, an area associated to working memory and selective attention, should exist to compensate a putative effect of the interaction between these dopaminergic genes.

The acute effect of methylphenidate in Brazilian male children and adolescents with ADHD: A randomized clinical trial

Objective: To evaluate the acute efficacy of methylphenidate (MPH) in Brazilian male children and adolescents with ADHD. Method: In a 4-day, double-blind, placebo-controlled, randomized, fix dose escalating, parallel-group trial, 36 ADHD children and adolescents were allocated to two groups: MPH (n = 19) and placebo (n = 17). Participants were evaluated pre- and posttreatment using the 10-item Conners Abbreviated Rating Scale (ABRS), the Children’s Global Assessment Scale (CGAS), and a simplified version of the Continuous Performance Test (CPT). Results: The MPH group had a significantly greater decrease in ABRS scores and a significantly higher increase in CGAS scores than the placebo group (p < 0.01). The MPH group showed also a significantly higher proportion of patients with a robust improvement (decrement of at least 50% in the ABRS score after the intervention) than the placebo group (p < 0.01). The MPH effect size for the ABRS was 1.05 (95% CI = 0.73-1.37). Conclusion: Our results extend the efficacy of MPH on the ADHD core symptoms extensively demonstrated in clinical trials with samples from some developed countries to a sample from a developing country where a diverse culture may modulate the clinical presentation of the disorder.