ADHD and thyroid abnormalities: a research note

Does Exposure to General Anesthesia Increase Risk of ADHD for Children Before Age of Three?

Objective: The objective of the study was to evaluate the relationship between frequency of exposure to general anesthesia before the age of 3 and subsequent risk of diagnosis for attention-deficit hyperactivity disorder (ADHD). Method: We searched PubMed, Embase, Web of Science, and Cochrane Library database for eligible inclusion in the meta-analysis. The indicated outcomes were extracted from the included studies, and the combined effects were calculated using the RevMan software 5.3. Results: Compared with no exposure to general anesthesia, single exposure to general anesthesia did not increase the risk of ADHD for children before the age of 3 [hazard ratio (HR): 1.14, 95%; confidence intervals (CI): 0.97-1.35; p = 0.11; I ² = 0%], while multiple exposures to general anesthesia did increase the risk of ADHD (HR: 1.83; 95% CIs: 1.00-3.32; p = 0.05; I ² = 81%). Conclusion: Multiple, but not single, exposures to general anesthesia in children before age of 3 increased the risk of ADHD.

The association between thyroid function biomarkers and attention deficit hyperactivity disorder

The relation between thyroid function biomarkers and attention deficit hyperactivity disorder (ADHD) in children and adolescents is currently unclear. Cross-sectional data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS Baseline) was analyzed to assess the association between thyroid function biomarkers and ADHD in a population-based, nationally representative sample. The study cohort included 11,588 children and adolescents with 572 and 559 having an ADHD diagnosis or symptoms, respectively. ADHD symptoms were assessed through the Inattention/Hyperactivity subscale of the Strength and Difficulties Questionnaire. ADHD diagnosis was determined by a physician or psychologist. Serum thyroid stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) concentrations were determined enzymatically. Adjusted regression models were used to relate serum TSH, fT3, and fT4 with risk for ADHD diagnosis or symptoms. In children, a 1 mIU/l higher TSH was related to a 10% lower risk (odds ratio [OR] 0.90; 95% confidence interval [CI] 0.81-1.00) of ADHD diagnosis. We found a significant positive association between fT3 and continuously assessed ADHD symptoms in children (β 0.08; 95% CI 0.03-0.14). Our results suggest that physical maturity may influence the association between thyroid function biomarkers and risk for ADHD.

Correlation between attention-deficit/hyperactivity disorder, its pharmacotherapy and thyroid dysfunction: A nationwide population-based study in Taiwan

OBJECTIVE

The aim of this study was to examine the comorbid rates of thyroid dysfunction among patients with attention-deficit/hyperactivity disorder (ADHD) and the general population. We further examined whether pharmacotherapy affects ADHD patients' risk of developing thyroid dysfunction.

DESIGN AND MEASUREMENT

We recruited 75 247 newly diagnosed ADHD patient and 75 247 healthy controls between January 1999 and December 2011 from the National Health Insurance database in Taiwan. We compared hyperthyroidism, hypothyroidism and other common paediatric psychiatric diseases between ADHD patients and controls. We carried out logistic regression analysis to identify an independent factor for predicting thyroid dysfunction. Furthermore, we analysed the time sequence of the diagnosis and the risk of developing a thyroid disorder after receiving pharmacotherapy.

RESULTS

Compared to the control group, the ADHD group had higher comorbidity rates of both hyperthyroidism (1.1% of ADHD vs 0.7% of controls, aOR: 1.72, P < 0.001) and hypothyroidism (0.6% of ADHD vs 0.2% of controls, aOR: 2.23, P < 0.001). Of the ADHD patients with comorbid thyroid dysfunction, about two-thirds and half of patients were diagnosed with ADHD prior to their diagnosis of hyperthyroidism and hypothyroidism, respectively. Furthermore, pharmacotherapy had no significant influence on the risk of developing hyperthyroidism (aHR: 1.09, P = 0.363) or hypothyroidism (aHR: 0.95, P = 0.719) among ADHD patients.

CONCLUSION

Patients with ADHD had greater comorbid rates with thyroid dysfunction than the control subjects, but pharmacotherapy for treating ADHD did not affect thyroid dysfunction later in life. However, these findings should be further verified using a clinical cohort with comprehensive laboratory assessment in future.

A Preliminary Investigation of the Relation Between Thyroid Functioning and Sluggish Cognitive Tempo in Children

OBJECTIVE

To test the hypothesis that thyroid functioning would be uniquely associated with sluggish cognitive tempo (SCT) symptoms but not Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) symptoms of ADHD.

METHOD

Serum thyroid stimulating hormone (TSH) was collected from a sample of psychiatrically hospitalized children ( N = 570; ages = 6-12), with rates of TSH similar to those found in the normative pediatric population. Caregivers completed narrowband measures of SCT and ADHD symptoms and broadband measures of internalizing/externalizing symptoms.

RESULTS

A significant, positive relation was found between TSH concentration and SCT symptoms, but not between TSH and ADHD symptoms. Furthermore, regression analyses indicated that the association between TSH and SCT remained significant after controlling for child demographic characteristics, broadband measures of internalizing and externalizing symptoms, and ADHD symptoms. However, effects were small in magnitude.

CONCLUSION

Although preliminary, results indicate that thyroid functioning may be related to SCT. Given the small effects, however, it is important for future research to examine other endocrine and biological correlates that may inform models of the developmental psychopathology of SCT.

Association of attention-deficit/hyperactivity disorder with diabetes: a population-based study

BACKGROUND

Cognitive impairment has been documented in adult diabetes but is unclear in pediatric diabetes. No study had been conducted to explore the relationship between attention-deficit/hyperactivity disorder (ADHD) and diabetes. Using a population-based data set, we aimed to examine the association between ADHD and a prior diagnosis of diabetes mellitus (DM) in Taiwan.

METHODS

A total of 4,302 patients with ADHD were selected as cases and 21,510 randomly selected subjects as controls. We used conditional logistic regression to calculate the odds ratio (OR) for having previously received a diagnosis of DM between subjects with and without ADHD.

RESULTS

In this study, 116 of the 25,812 sampled subjects (0.5%) had received a diagnosis of DM prior to their index date. Subjects with ADHD had a higher proportion of prior DM diagnoses than controls (0.9% vs. 0.4%, P < 0.001). After adjusting for age, sex, index year, geographic location, and obesity, ADHD was significantly associated with a prior diagnosis of type 2 DM (OR = 2.75, 95% confidence interval (CI) = 1.82-4.16). However, no significant association was observed between ADHD and type 1 DM.

CONCLUSION

The findings suggest that ADHD was associated with a previous diagnosis of type 2 DM.

Comorbidities in ADHD children treated with methylphenidate: a database study

BACKGROUND

Methylphenidate (MPH) is the most common drug treatment of attention deficit / hyperactivity disorder (ADHD) in children. Treatment with MPH is contraindicated in the presence of certain psychiatric, cerebro- and cardiovascular conditions. We assessed MPH treatment prevalence and incidence and the frequency of comorbid conditions related to these contraindications in new MPH users compared to a control group without ADHD and ADHD medication.

METHODS

We used health care data for the years 2004 to 2006 from the German Pharmacoepidemiological Research Database (GePaRD) which includes about 18% of the German population. MPH treatment prevalence and incidence was assessed based on at least one MPH prescription in the given year. In MPH users, the prevalence of psychiatric and other comorbidities was assessed in the quarter of the first MPH prescription and the three preceding quarters, whereas in controls it was assessed in the earliest four quarters of continuous insurance time starting at 01.01.2004 or the start of insurance if this was later. Differences in the presence of comorbid diagnoses between MPH users and controls were tested by logistic regression.

RESULTS

In 2005, 1.5% of all children and adolescents aged 3 to 17 years (2.3% of males and 0.6% of females) received MPH in Germany. The proportion of children with a record of a psychiatric comorbidity in any of the nine ICD categories of diagnoses was substantially higher in new MPH users (83%) compared to controls (20%). Cerebro- and cardiovascular comorbidities were rare in general. Still, among new MPH users, 2% of males and females had a diagnosis of a pre-existing cardiovascular disorder but only 1.2% of controls.

CONCLUSIONS

Besides MPH treatment prevalence we first publish age-specific incidence rates for Germany. A high proportion of children who were started on MPH had a record of a psychiatric comorbidity preceding the first prescription. Cerebro- and cardiovascular conditions were rare in the studied age range, but still higher among children who received MPH than in the control group. Results show that in a substantial subgroup of patients, comorbidities require a thorough weighting of possible risks of MPH medication against the risks of untreated ADHD.

Why most biomedical findings echoed by newspapers turn out to be false: the case of attention deficit hyperactivity disorder

Context

Because positive biomedical observations are more often published than those reporting no effect, initial observations are often refuted or attenuated by subsequent studies.

Objective

To determine whether newspapers preferentially report on initial findings and whether they also report on subsequent studies.

Methods

We focused on attention deficit hyperactivity disorder (ADHD). Using Factiva and PubMed databases, we identified 47 scientific publications on ADHD published in the 1990s and soon echoed by 347 newspapers articles. We selected the ten most echoed publications and collected all their relevant subsequent studies until 2011. We checked whether findings reported in each “top 10” publication were consistent with previous and subsequent observations. We also compared the newspaper coverage of the “top 10” publications to that of their related scientific studies.

Results

Seven of the “top 10” publications were initial studies and the conclusions in six of them were either refuted or strongly attenuated subsequently. The seventh was not confirmed or refuted, but its main conclusion appears unlikely. Among the three “top 10” that were not initial studies, two were confirmed subsequently and the third was attenuated. The newspaper coverage of the “top 10” publications (223 articles) was much larger than that of the 67 related studies (57 articles). Moreover, only one of the latter newspaper articles reported that the corresponding “top 10” finding had been attenuated. The average impact factor of the scientific journals publishing studies echoed by newspapers (17.1 n = 56) was higher (p<0.0001) than that corresponding to related publications that were not echoed (6.4 n = 56).

Conclusion

Because newspapers preferentially echo initial ADHD findings appearing in prominent journals, they report on uncertain findings that are often refuted or attenuated by subsequent studies. If this media reporting bias generalizes to health sciences, it represents a major cause of distortion in health science communication.

Attention-deficit/hyperactivity disorder after early exposure to procedures requiring general anesthesia

OBJECTIVE

To study the association between exposure to procedures performed under general anesthesia before age 2 years and development of attention-deficit/hyperactivity disorder (ADHD).

PATIENTS AND METHODS

Study patients included all children born between January 1, 1976, and December 31, 1982, in Rochester, MN, who remained in Rochester after age 5. Cases of ADHD diagnosed before age 19 years were identified by applying stringent research criteria. Cox proportional hazards regression assessed exposure to procedures requiring general anesthesia (none, 1, 2 or more) as a predictor of ADHD using a stratified analysis with strata based on a propensity score including comorbid health conditions.

RESULTS

Among the 5357 children analyzed, 341 ADHD cases were identified (estimated cumulative incidence, 7.6%; 95% confidence interval [CI], 6.8%-8.4%). For children with no postnatal exposure to procedures requiring anesthesia before the age of 2 years, the cumulative incidence of ADHD at age 19 years was 7.3% (95% CI, 6.5%-8.1%). For single and 2 or more exposures, the estimates were 10.7% ( 95% CI, 6.8%-14.4%) and 17.9% ( 95% CI, 7.2%-27.4%), respectively. After adjusting for gestational age, sex, birth weight, and comorbid health conditions, exposure to multiple (hazard ratio, 1.95; 95% CI, 1.03-3.71), but not single (hazard ratio,1.18; 95% CI, 0.79-1.77), procedures requiring general anesthesia was associated with an increased risk for ADHD.

CONCLUSION

Children repeatedly exposed to procedures requiring general anesthesia before age 2 years are at increased risk for the later development of ADHD even after adjusting for comorbidities.

Etiologic classification of attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder is a neurobiological syndrome with an estimated prevalence among children and adolescents of 5%. It is a highly heritable disorder, but acquired factors in etiology are sometimes uncovered that may be amenable to preventive measures or specific therapy. Early reports have described symptoms similar to attention-deficit/hyperactivity disorder that followed brain trauma or viral encephalitis, and recent MRI studies have demonstrated brain volumetric changes that may be involved in the pathophysiology of the syndrome. The American Psychiatric Association's Diagnostic Statistical Manual, introduced in 1968, emphasizes symptomatic criteria in diagnosis. Here, an overview of environmental factors in the etiology of attention-deficit/hyperactivity disorder is presented to encourage more emphasis and research on organic causal factors, preventive intervention, and specific therapies. An organic theory and the genetic and biochemical basis of attention-deficit/hyperactivity disorder are briefly reviewed, and an etiologic classification is suggested. Environmental factors are prenatal, perinatal, and postnatal in origin. Pregnancy- and birth-related risk factors include maternal smoking and alcohol ingestion, prematurity, hypoxic-ischemic encephalopathy, and thyroid deficiency. Childhood illnesses associated with attention-deficit/hyperactivity disorder include virus infections, meningitis, encephalitis, head injury, epilepsy, toxins, and drugs. More controversial factors discussed are diet-related sensitivities and iron deficiency. Early prenatal recognition, prevention, and treatment of environmental etiologies of attention-deficit/hyperactivity disorder may reduce physician reliance on symptomatic modification with medication, a frequent reason for parental concern.

Height, weight, IGF-I, IGFBP-3 and thyroid functions in prepubertal children with attention deficit hyperactivity disorder: effect of methylphenidate treatment

OBJECTIVE

To investigate if there are any disease-related or methylphenidate-induced aberrations in growth parameters, growth hormone insulin-like growth factor (IGF)-I, IGFBP-3 axis and the thyroid function tests in children with attention deficit hyperactivity disorder (ADHD).

METHODS

Newly diagnosed and untreated prepubertal children with ADHD were longitudinally followed before and approximately every 4 months after methylphenidate treatment for up to 16 months. Height SDS, weight SDS, BMI SDS, serum GH, IGF-I, IGFBP-3, T4, free T4, T3, and TSH were measured at each visit.

RESULTS

All of the examined parameters were within normal limits for age before treatment. Methylphenidate treatment did not significantly affect SDS of height, weight, BMI, IGF-I and IGFBP-3 in the long run. Serum T4 and free T4 levels showed modest reductions within normal limits in a time-dependent manner.

CONCLUSIONS

Prepubertal children with ADHD had normal height, weight, BMI, serum IGF-I and IGFBP-3 and thyroid functions. Methylphenidate treatment had no sustained effects on growth parameters, IGF-I and IGFBP-3 during the follow-up period of this study. However, it caused a mild decrease in total and free T4 which may warrant further monitoring.

Thyroid function tests and neurocognitive functioning in children referred for attention deficit/hyperactivity disorder

BACKGROUND

Thyroid abnormalities have been associated with attention deficit/hyperactivity disorder (ADHD) and with other childhood psychiatric disorders. The goal of this study was to determine the relationships between thyroid hormone concentrations, neurocognitive functioning, and psychiatric diagnosis in children.

METHODS

Free thyroxine index (FT4I) and thyroid stimulating hormone (TSH) were obtained, along with diagnostic and descriptive information for 338 children referred to a clinic specializing in learning and behavior problems.

RESULTS

Thyroid abnormalities were uncommon in children referred for ADHD. After excluding children with thyroid disease, there was a greater proportion with low concentrations of normal FT4I for ADHD-Predominantly Inattentive type (ratio=7.0), but not for ADHD-Combined Type. High concentrations of normal FT4I were associated with mood lability, preoccupations, and lower ratings of attention problems. Thyroxine concentrations within the normal range were differentially associated with ADHD-Combined Type compared to ADHD-Predominantly Inattentive, mood disorders, and pervasive developmental disorders.

CONCLUSION

Thyroxine concentrations were associated with mood symptoms and unusual behaviors, and were less strongly related to attentional functioning. Thyroxine concentrations were not related to hyperactivity.

Newborn thyroxine levels and childhood ADHD

OBJECTIVES

Normal brain development is highly dependent on adequate levels of iodine and thyroid hormone. It has been suggested that Attention Deficit Hyperactivity Disorder (ADHD) is the consequence of prenatal thyroidal endocrine disruption. The hypothesis was examined using neonatal thyroxine levels as a bio-marker of prenatal thyroid status and comparing it to subsequent development of ADHD.

DESIGN AND METHODS

In a matched case-control study, cases were defined as children diagnosed with ADHD, while children born in the same hospital and tested on the same day served as matched controls. Conditional logistic regression analysis with unequal numbers of controls was performed.

RESULTS

The neonatal thyroxine levels were within normal limits for each of the children who were subsequently diagnosed as having ADHD, and their distribution was no different from that of their controls.

CONCLUSIONS

Children diagnosed with ADHD do not demonstrate prenatal thyroidal dysfunction as reflected in the newborn thyroxine levels, therefore neonatal thyroxine levels are not a bio-marker for the subsequent development of ADHD.

Prevalence and assessment of attention-deficit/hyperactivity disorder in primary care settings

Research literature relating to the prevalence of attention-deficit/hyperactivity disorder (ADHD) and co-occurring conditions in children from primary care settings and the general population is reviewed as the basis of the American Academy of Pediatrics clinical practice guideline for the assessment and diagnosis of ADHD. Epidemiologic studies revealed prevalence rates generally ranging from 4% to 12% in the general population of 6 to 12 year olds. Similar or slightly lower rates of ADHD were revealed in pediatric primary care settings. Other behavioral, emotional, and learning problems significantly co-occurred with ADHD. Also reviewed were rating scales and medical tests that could be employed in evaluating ADHD. The utility of using both parent- and teacher-completed rating scales that specifically assess symptoms of ADHD in the diagnostic process was supported. Recommendations were made regarding the assessment of children with suspected ADHD in the pediatric primary care setting.

Clinical practice guideline: diagnosis and evaluation of the child with attention-deficit/hyperactivity disorder. American Academy of Pediatrics

This clinical practice guideline provides recommendations for the assessment and diagnosis of school-aged children with attention-deficit/hyperactivity disorder (ADHD). This guideline, the first of 2 sets of guidelines to provide recommendations on this condition, is intended for use by primary care clinicians working in primary care settings. The second set of guidelines will address the issue of treatment of children with ADHD. The Committee on Quality Improvement of the American Academy of Pediatrics selected a committee composed of pediatricians and other experts in the fields of neurology, psychology, child psychiatry, development, and education, as well as experts from epidemiology and pediatric practice. In addition, this panel consists of experts in education and family practice. The panel worked with Technical Resources International, Washington, DC, under the auspices of the Agency for Healthcare Research and Quality, to develop the evidence base of literature on this topic. The resulting evidence report was used to formulate recommendations for evaluation of the child with ADHD. Major issues contained within the guideline address child and family assessment; school assessment, including the use of various rating scales; and conditions seen frequently among children with ADHD. Information is also included on the use of current diagnostic coding strategies. The deliberations of the committee were informed by a systematic review of evidence about prevalence, coexisting conditions, and diagnostic tests. Committee decisions were made by consensus where definitive evidence was not available. The committee report underwent review by sections of the American Academy of Pediatrics and external organizations before approval by the Board of Directors. The guideline contains the following recommendations for diagnosis of ADHD: 1) in a child 6 to 12 years old who presents with inattention, hyperactivity, impulsivity, academic underachievement, or behavior problems, primary care clinicians should initiate an evaluation for ADHD; 2) the diagnosis of ADHD requires that a child meet Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria; 3) the assessment of ADHD requires evidence directly obtained from parents or caregivers regarding the core symptoms of ADHD in various settings, the age of onset, duration of symptoms, and degree of functional impairment; 4) the assessment of ADHD requires evidence directly obtained from the classroom teacher (or other school professional) regarding the core symptoms of ADHD, duration of symptoms, degree of functional impairment, and associated conditions; 5) evaluation of the child with ADHD should include assessment for associated (coexisting) conditions; and 6) other diagnostic tests are not routinely indicated to establish the diagnosis of ADHD but may be used for the assessment of other coexisting conditions (eg, learning disabilities and mental retardation). This clinical practice guideline is not intended as a sole source of guidance in the evaluation of children with ADHD. Rather, it is designed to assist primary care clinicians by providing a framework for diagnostic decisionmaking. It is not intended to replace clinical judgment or to establish a protocol for all children with this condition and may not provide the only appropriate approach to this problem.

The treatment of attention-deficit hyperactivity disorder: an annotated bibliography and critical appraisal of published systematic reviews and metaanalyses

CONTEXT

The Agency for Health Care Policy and Research charged the McMaster Evidence-based Practice Center with conducting a comprehensive systematic review of the literature on the treatment of attention-deficit hyperactivity disorder (ADHD), with input from various groups of stakeholders. One strategy used to avoid duplication of work included a critical appraisal of existing systematic reviews and metaanalyses.

OBJECTIVE

To identify and appraise published metaanalyses and systematic reviews on the treatment of ADHD and to produce an annotated bibliography.

DATA SOURCES

Medline, Cumulative Index in Nursing and Allied Health (CINAHL), Healthstar, Psycinfo, and Embase were searched to September 1998; the Cochrane Database (1998 issue 3), selected Internet sites, and the files of investigators were also reviewed.

STUDY SELECTION

Review articles described as systematic reviews or metaanalyses or including a Methods section were identified independently by 3 reviewers.

DATA EXTRACTION

Two reviewers extracted, by consensus, relevant information on the name, methodological quality, ADHD-related aspects (comorbid disorders, family characteristics) of those reviews; data on the population, study setting, interventions, and outcomes evaluated by the reviews were also retrieved.

RESULTS

Thirteen reviews, published from 1982 to 1998, were included. Eight included metaanalysis and 5 a qualitative review. Nonpharmacological treatments were mentioned in 6 reviews and combination therapies in 3. One review focused on the treatment of adults. Forty-seven drugs and 20 adverse effects were mentioned. Most reviews had major methodological flaws.

CONCLUSIONS

Most published systematic reviews and metaanalyses on the treatment of ADHD have limited value for guiding clinical, policy, and research decisions. A rigorous, systematic review following established methodological criteria is warranted.

Neuropsychiatric aspects of pediatric thyrotoxicosis

The neurobehavioural and neuropsychiatric changes associated with thyrotoxicosis are multiple and varied. This association is well recognised although the true incidence of neuropsychiatric symptoms in thyrotoxicosis is not known. Review of available literature suggests that frank psychiatric symptoms in thyrotoxicosis may be in the order of 10%. In pediatric thyrotoxicosis the neuropsychiatric symptoms may be pronounced and may antedate the medical diagnosis by six months to one year. One of the classic presentation is deterioration in school performance. Frequently noticed cognitive and behavioural abnormalities in pediatric thyrotoxicosis are hyperactivity, irritability or anxious dysphoria, and problems of attention. Successful treatment of thyrotoxicosis usually leads to resolution of the major mental disturbances associated with it and delayed treatment possibly results in enduring neuropsychiatric problems. Awareness of neuropsychiatric symptomatology can help in early detection and appropriate management of children with thyrotoxicosis.

Practice parameters for the assessment and treatment of children, adolescents, and adults with attention-deficit/hyperactivity disorder. American Academy of Child and Adolescent Psychiatry

These practice parameters review the literature on children, adolescents, and adults with attention-deficit/hyperactivity disorder (ADHD). There are three types of ADHD: predominantly inattentive, predominantly hyperactive-impulsive, and combined. Together, they occur in as many as 10% of boys and 5% of girls of elementary school age. Prevalence declines with age, although up to 65% of hyperactive children are still symptomatic as adults. Frequency in adults is estimated to be 2% to 7%. Assessment includes clinical interviews and standardized rating scales from parents and teachers. Testing of intelligence and academic achievement usually are required. Comorbidity is common. The cornerstones of treatment are support and education of parents, appropriate school placement, and pharmacology. The primary medications are psychostimulants, but antidepressants and alpha-adrenergic agonists are used in special circumstances. Other treatments such as behavior modification, school consultation, family therapy, and group therapy address remaining symptoms.

Thyroid function in attention deficit and hyperactivity disorder

In view of the recent conflicting findings regarding the causative role of thyroid abnormalities in attention deficit hyperactivity disorder (ADHD), we performed a replication study to clarify the issue and establish clinical guidelines. Thyroid tests were performed in 43 ADHD children and 28 age- and gender-matched controls. Sixteen ADHD children showed total triiodothyronine (TT3) levels which were slightly above the upper limit of normal, but no significant difference in TT3 values was noted between the ADHD and the control groups. Moreover, none of the ADHD subjects had abnormal levels of total thyroxine, free thyroxine, thyroid stimulating hormone or total triiodothyronine reuptake. The present study supplies additional evidence for the lack of an association between thyroid function and ADHD, and counters the suggestion that thyroid function be routinely screened for in ADHD children.

Attention-deficit hyperactivity disorder. In pursuit of diagnostic accuracy

Attention-deficit behaviors create a substantial burden for healthcare facilities. The incidence of ADHD is estimated at 5% to 10% of school-age children, but it is possible that many diagnoses of ADHD are flawed. At present, because the etiology of the disorder is not well understood, the diagnosis of ADHD by DSM-IV criteria hinges on the presence of inattention, hyperactivity, impulsivity, or a combination of these. Children who do not have ADHD also exhibit such behaviors in certain environments, as do children with learning disorders, family relational problems, and emotional difficulties. Thus it is imperative that physicians take a comprehensive approach to diagnosis when a child presents with behavioral difficulties. Noting that a number of myths about ADHD (eg, that improved behavior after being given stimulant medication proves a diagnosis of ADHD) have recently gained currency, the authors recommend going beyond the first step of behavior checklists in diagnosing the disorder and describe situations in which further assessment is indicated.

Attention Deficit Hyperactivity Disorder (ADHD): Selected review of causes, comorbidity and treatment

A limited review of the causes, comorbidity, diagnosis and treatment is offered to emphasize the difficulties in diagnosing and treating Attention Deficit Hyperactivity Disorder and Hyperkinetic Disorder. Some of the difficulties include controversies about the existence of a separate disorder, the changes in symptoms with age, the short-lived improvement on medication and the claims of unsubstantiated treatments. This selected review should help the reader to consider recent findings in the aetiology, diagnosis and treatment of ADHD.

Utility of thyroid function screening in adolescent psychiatric inpatients

OBJECTIVE

Thyroid function abnormalities have been associated with psychiatric symptoms. This study examines the utility of thyroid screening among adolescent psychiatric inpatients.

METHOD

A retrospective chart review of 196 first-time admissions to an adolescent psychiatric unit was conducted. Charts were screened for demographics, presence/absence of thyroid function testing, history of thyroid disease, medication/illicit substance use, and other factors of influence on thyroid testing. Thyroid test results were reviewed for abnormalities.

RESULTS

Thyroid function testing was conducted in 150 of the 196 admissions. Fifty-two patients had abnormalities, most of which were isolated abnormalities of thyroxine (T4) or triiodothyronine uptake (T3U). Laboratory diagnosis of hyperthyroidism and mild hypothyroidism was met by two and eight patients, respectively; five had profiles that were normal upon subsequent testing 1 week later. None of the patients was symptomatic, and none required thyroid supplementation or antithyroid medications. Gender differences in T4 and T3U were noted, and age was positively correlated with T3U.

CONCLUSIONS

Thyroid function tests may be spuriously abnormal in routine screening of newly admitted psychiatric patients. Routine thyroid screening among adolescent psychiatric inpatients is unwarranted except in patients who display physical signs or symptoms suggestive of thyroid disease.

Thyroid hormone and attention in school-age children with congenital hypothyroidism

The relationship between attention and thyroid hormone was examined using a retrospective database of 85 7-year-old children with congenital hypothyroidism who received psychological evaluations and thyroid function tests on the same day. Four unique subgroups with different levels of thyroxine and thyrotropin were compared on psychological tasks and measures of attention. Children with high levels of both hormones were found to be significantly more distractable on an index of cognitive attention but were reportedly less hyperactive. Level of thyroxine accounted for over 10% of the variance in attention.