Olavo B. Amaral

The article by Guilherme Polanczyk, M.D., et al, in the June 2007 issue of the American Journal of Psychiatry provides important insights pertaining to the worldwide prevalence of childhood attention deficit hyperactivity disorder (ADHD). Dr. Polanczyk et al. convincingly argued that symptoms of ADHD may have a more constant geographic prevalence than previously thought. However, the accompanying editorial may have overestimated the implications of these findings.

The statement that a constant prevalence of ADHD symptoms argues in favor of "ADHD’s identity as a bona fide mental disorder, as opposed to a social construction" ( p. 856) may be misinterpreting the nature of psychiatric nosology. The concept of a disorder and its diagnostic criteria are social constructions by definition, and the fact that a group of symptoms has a constant geographic prevalence has little to do with what leads these symptoms to be considered a diagnostic entity. Twin pregnancies, for example, are observed worldwide with limited prevalence variation; however, being a twin in some indigenous cultures in Africa and South America could lead a child to be left to die or to be attributed with supernatural powers, whereas the same biological occurrence has far less relevance in modern Western society. Thus, universal phenomena can be viewed as normal or dysfunctional according to cultural beliefs.

Perhaps the best way to judge whether ADHD is a social construction, therefore, is not to look at the worldwide prevalence of its symptoms, but rather to evaluate the prevalence of its recognition and treatment. In this area, differences are striking. The per capita consumption of methylphenidate in the United States between 2003 and 2005 was approximately six times greater than that of Australia, eight times greater than that of Spain, and 18 times greater than that of Chile. If the prevalence of hyperactive symptoms is indeed similar among these countries, this probably means that a "hyperactivity disorder" deserving treatment in one country is seen by parents and physicians as a nonmedical condition (perhaps at the higher end of the "childhood activity spectrum") elsewhere.

It is in defining such a diagnostic threshold that lies the social construction, as the boundaries of normality in a given region are set by psychiatrists (by choosing and applying diagnostic criteria) and society (by recognizing symptoms as deserving of medical care). Thus, it is probably not useful to ask whether DSM-IV has too low a threshold for ADHD or whether ICD-10 has too high a threshold, since there is little evidence of a biological threshold to be identified; the definition of such a threshold is the collective social duty of physicians, parents, and society.

It is crucial that we acknowledge not only the existence of this construction, but also the responsibilities inherent in taking part in it. Symptoms might be constant throughout the world, but it is how we view them that will give them meaning and define the care of children worldwide.

2. Drs. Polanczyk and Rohde Reply

Guilherme Polanczyk, M.D. and Luis Augusto Rohde, , M.D., Ph.D.

We appreciate the thoughtful views of Dr. Amaral. It is of paramount importance to discuss the perceptions of physicians and patients concerning mental health disorders. This is the only way that we can counter the stigma surrounding them. Cultural stigma is an important barrier to recognition and treatment of illnesses, particularly mental disorders, including ADHD.

Nevertheless, economic factors seem to be a major impediment to their successful management. In the United States, a survey of more than 100,000 families revealed that uninsured children and children of racial/ethnic minority populations were less likely than others to be receiving medications for ADHD. There is a significant gap between the needs and provisions of mental health services in virtually every country, especially in developing countries. In a Brazilian sample of 100 nonreferred subjects identified with ADHD in schools, only three subjects were currently receiving treatment. The same findings were revealed in a Venezuelan community survey, in which only 4% of children identified with ADHD by researchers were receiving treatment (unpublished study by Montiel-Nava et al. available upon request from the authors).

As Dr. Amaral points out, it is true that "universal phenomena can be viewed as normal or dysfunctional according to cultural beliefs." Psychiatric diagnostic criteria are based on conceptual theories, but not only on such theories. Empirical evidence supports the validity of ADHD diagnostic criteria, as well as the validity of several other medical conditions, even if specific cultures legitimize their occurrence as "normal" or "desirable." For instance, there is a higher prevalence of obesity among individuals of Pacific Island cultures compared with those of European ethnicity. This is probably related to economic factors and a cultural desire for bigger bodies. Nevertheless, the link between obesity and several adverse outcomes is well established, supporting its validity as a medical condition.

It has been demonstrated that the variability of estimates of ADHD prevalence in diverse locations around the world seems to be largely explained by methodological artifacts and not by demographic differences. This indicates that ADHD diagnostic criteria identify a similar frequency of an underlying construct in different locations, independent of local judgments. As previously pointed out, this does not mean that environmental factors are not involved in the etiological process. In fact, emerging evidence indicates that mental disorders are the result of complex interaction between genetic and environmental factors. It is clear that biological and cultural factors must be studied in conjunction, not only for a more comprehensive understanding of scientific phenomena, but also to implement effective treatment plans.

3. Risperidone-to-methylphenidate switch reaction in children: three cases.

Sabuncuoglu O.
Department of Child Psychiatry, School of Medicine, Marmara University, Istanbul, Turkey.

J Psychopharmacol. 2007 Mar; 21(2): 216-9

As atypical antipsychotics are increasingly used in the treatment of childhood behavioural disorders either as monotherapy or in combination with other medications, there is a need to know more about their safety, in particular during switching to and from methylphenidate treatment, as antipsychotics and methylphenidate have opposing effects on dopaminergic neurotransmission. This report is about three cases of children who developed severe adverse reactions during switching from risperidone to methylphenidate. The first patient was a 6-year-old boy, diagnosed with attention deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD).

He developed severe hyperactivity and agitation on taking methylphenidate after the discontinuation of risperidone treatment. The second patient was a girl of 6, already on risperidone for ADHD and borderline intellectual functioning when referred. She displayed severe hyperactivity, agitation and irritability upon switching to methylphenidate medication. The third patient was a 15-year-old female adolescent with a similar clinical course as the previous patients.

In all the cases described here, it is only with the discontinuation of methylphenidate that the adverse reactions resolved and readministration of methylphenidate in two patients did not produce any adverse effect after a drug-free interval. Functional regulation of certain neuroreceptors during risperidone treatment may lead to altered behavioural responses upon switching to methylphenidate. Thus, a drug-free interval is recommended in order to prevent adverse reactions.

4. Societal Costs and Quality of Life of Children Suffering From Attention Deficit Hyperactivity Disorder (ADHD)

Hakkaart-van Roijen L, Zwirs BW, Bouwmans C, et al.

Eur Child Adolesc Psychiatry. 2007

Study Design: This study assessed the direct medical costs of a sample of children with ADHD, the medical costs of their mothers, and overall quality of life. The sample included 70 children treated by a pediatrician for DSM-IV diagnosed ADHD, a nonmatched group of 35 children with behavior problems, and 60 children with no behavior problem. This group of children was part of a large school population-based study of the detection of ADHD. Health care utilization of the children was based upon the Trimbos and iMTA questionnaire on Costs associated with Psychiatric illness' (TiC-P). Health-related quality of life was assessed with the Dutch 50-item parent version of the Child Health Questionnaire (CHQ PF-50). Measurements were taken at baseline and at 6 months. Investigators also collected data on the health utilization of the mothers and their production losses due to absence from work and reduced efficiency.

Results: The mean direct medical costs per ADHD patient per year were € 2040 (or €1173 when leaving out 1 patient with a long-term hospital admission), compared with €288 for the group of children with behavior problems and €177 for the group of children with no behavior problems. The direct medical costs for children who had psychiatric comorbidities were significantly higher compared with children with ADHD alone. The mean medical costs per year for the mothers of children with ADHD were significantly higher (€728) than for the mothers of the children with behavior problems (€202) and the mothers of children with no behavior problems (€154).

The physical summary score showed no significant differences between the groups. However, the psychosocial summary score dimension scores were significantly lower for ADHD patients compared with scores of the children in the 2 other samples. The mean annual indirect costs related to absence from work and reduced efficiency at work were €2243 for the mothers of children with ADHD compared with €408 for the mothers of children with behavior problems and €674 for the mothers of children with no behavior problems.

Conclusion: This study from the Netherlands showed that the direct medical costs of ADHD patients were relatively high. In addition, ADHD was accompanied by increased indirect costs for this group, with elevated rates in work absenteeism and reduced efficiency.

Commentary: This study demonstrates the importance of taking a broad view of the child with ADHD, to consider the impact on the daily lives of working families. Previous reports have compared the impact of the disorder on the quality of life of children with ADHD and their families to other populations, including children with medical conditions, such as asthma.

5. Tic Severity in Tourette Syndrome: Relationship to Co-morbid Attention Deficit Hyperactivity Disorder and Obsessive Compulsive Disorder

Tamara Pringsheim, MD, Division of Neurology, University of Toronto, Toronto, Ontario, Canada

October 12, 2007 -- Annual Meeting of the American Neurological Association (

ADHD is present in about 60% of children with TS, and OCD occurs in approximately 30% of children with TS.
The study enrolled 94 children: 27 with TS only; 33 with TS + ADHD; 12 with TS + OCD; and 22 TS patients with both ADHD + OCD. The mean age of the subjects was 11.1 years (range 7-17); 83% were male.

Tic severity was assessed using the Yale Global Tic Severity Scale (YGTSS), which measures both tic severity and the impairment associated with tics (social, self-image, quality of life). A higher YGTSS value indicates greater severity.
Mean YGTSS tic score, and the mean YGTSS tic plus impairment score, were significantly (P <.05) higher in the children with TS + ADHD + OCD than in those with TS only, or in those with TS + ADHD.

The percentage of children taking medication to control their tics was also significantly (P <.05) higher in the TS + ADHD + OCD group (73%) than in any of the other three groups -- TS (22%), TS + ADHD (45%), TS + OCD (25%).
Tics typically become more severe in high-stress situations. The report suggests, therefore, that the greater tic severity reported in children with all three disorders may be the result of greater psychosocial stress due to multiple clinical problems. Alternatively, greater tic severity in those with children with TS + ADHD + OCD may be part of a more severe clinical phenotype.

Statistical analysis established that tic severity is significantly associated with multiple factors, including gender (higher YGTSS scores in males), diagnosis (TS, TS + ADHD, TS + OCD, or TS + ADHD + OCD), and treatment for ADHD (compared to no ADHD treatment; P <.02).

Dr. Pringsheim noted that studies from 20 or 30 years ago showed increased tic behaviour in children treated for ADHD. By contrast, recent studies, including this one, have demonstrated that medications for ADHD actually decrease tic severity, as borne out by lower YGTSS scores.