ADHD a hot topic at the AACAP conference

The 54th American Academy of Child & Adolescent Psychiatry (AACAP) Conference was successfully held at the Sheraton Boston Hotel in Boston from October 23rd to 28th 2007.1 Attention Deficit Hyperactive Disorder (ADHD) was a major theme. Dr Lawrence Greenhill gave three excellent presentations featuring the latest research into ADHD treatment in preschool aged children.

The 54th American Academy of Child & Adolescent Psychiatry (AACAP) Conference like its predecessors was a large success. Both international and local experts in the field were in attendance. Delegates received an excellent academic program consisting of plenary lectures, interactive workshops, research forums, poster sessions, symposiums and case based discussions, achieving an adequate balance between theory and practical applications.¹ A wide array of child and adolescent psychiatry topics were featured including neuroimaging techniques, ADHD, eating disorders, psychopharmacology, genetics, ethics, sexuality, neuropsychiatric development, substance abuse, genetics and autism spectrum disorders.¹ In addition, the most breaking research in these fields was presented.

One of the many highlights of the conference included the discussions of ADHD and its treatment in children. ADHD is a developmental disorder characterised by a persistent pattern or poor attention, hyperactivity, poor impulse control and distractibility. Although problems exist with our current diagnostic criteria, to achieve diagnosis according to DSM-IV (the gold standard), patients must have impairments in at least two different settings (for example home and school).² In addition, symptomatology must commence before 7 years of age and have a duration of greater than 6 months.² Patients are currently divided into inattentive and impulsive/hyperactive subtypes according to which category they achieve greater than 6 out of the 9 listed symptoms. Furthermore, symptoms must not be explicable by other psychiatric disorders such as anxiety, depression or pervasive development disorder. Current problems with diagnostic criteria will hopefully be addressed for the release of the DSM-V criteria.²

ADHD is one of the most common behavioural disorders of childhood. It is estimated to have a world wide prevalence of 5.2% but rates vary widely across countries. ADHD presents in childhood in 60% of cases but almost two thirds of cases can have persistence of symptoms into adolescent and adult life.² Today approximately 4% of adults meet DSM-IV criteria for ADHD.² The aetiology is not entirely understood but there is a strong heritability with up to 80% of patients having a positive family history. Maternal smoking, alcohol exposure and low birth weights are also thought to be contributing factors.² ADHD is not a trivial disorder and has the potential to cause significant impairment in a child’s social and educational functioning and lead to increased risk taking behaviours. It is not uncommon to meet refractory cases and almost two thirds have other co-morbid axis I DSM-IV psychiatric disorders (such as oppositional defiant and conduct disorders). Co-morbidity is thus described as the rule, not the exception and poses further impairments and challenges for treatment.

ADHD treatment has received large public attention in recent years due to controversies surrounding the diagnosis and apparent over-exposure of our children to psychostimulant medications. During the conference Dr Lawrence Greenhill, winner of the prestigious AACAP Elaine Schlosser Lewis Award for Research on Attention-Deficit Disorder, provided three riveting lectures of the latest evidence in this area. He presented findings of his ground-breaking research – The Preschooler ADHD Treatment (PAT) Study, which was a follow on from the previous MTA study of primary school aged children. Recognising the considerable use of stimulant medications in preschool kids, Dr. Greenhill challenged the Food and Drug Administration (FDA)’s warnings surrounding use of stimulant medication in children less than 6 years and the controversies of prescribing a drug of potential abuse to young children.⁴ As such the research team enrolled an initial cohort of 303 preschool children with moderate to severe ADHD to receive Methylphenidate hydrochloride (brand names Concerta, Ritalin) or placebo following parent education.

The research showed that the optimal doses (adjusted to height and weight) for pre-school children were lower than were expected. This is explained by pharmacokinetic studies that show young children clear methylphenidate at approximately half the rate of school age children, hence lower doses are associated with higher serum levels.⁴ The 85% response rate to methylphenidate was similar to that seen in the MTA study of primary school children but effects were not as brisk or robust.⁴ Authors postulated that the guarded effects may have been associated with the capped doses they were permitted to prescribe.^4,5 Adverse effects in this age group were generally similar to those in the primary age group but parents must be warned that young children may be more susceptible to tantrums, bouts of crying and irritability which were noted to be above the usual baseline. Growth was affected with increase in height 1.5cm less and weight 2.5kg less than predicted over the 375 days of the trial.⁵

Although participants enlisted in the PAT study had severe forms of ADHD and thus were not representative of the true population, the study provides evidence of the potential benefit of psychostimulant drugs in young children. However, to apply the results of this study safely, practitioners should ensure their patients meet all the criteria of the study. If so, practitioners can be more confident their patient will respond to medications, hence they may consider treatment.⁵ In addition, parents need to understand the uncertainties of diagnosis, the properties of the various drugs, and the risks of not treating. It is important to warn them about expected side-effects, identify any specific concerns, discuss benefit versus risk and obtain informed consent. They can be referred to valuable resources such as the parentsmedguide.org website.²

The above research findings were supplemented by Dr. Timothy Wilens’ presentation that provided an overview of the various psychopharmacology agents available for refractory cases of ADHD. FDA approved treatments for ADHD include stimulants (amphetamines and methylphenidate preparations), the non-stimulant atomoxetine (Strattera), and behavioural intervention. New preparations such as liz-dexamphetamine (a pro-drug stimulant) and alternative treatments such as buproprion (Zyban), tricyclics and clonidine were also discussed.³ ADHD sufferers now have access to more stimulant medication options including tablets, capsules, long duration capsules, osmotic release capsules, patches and pro-drugs offering potential for greater convenience.⁵ Take home messages of Dr. Wilens’ presentation included recognition of ADHD as a major disorder with refractory and co-morbid cases, encouraging adequate use of medications (including elevating the doses and monitoring blood levels if necessary) and prescribing combinations of medications which you are comfortable. In treating co-morbid cases, he recommended treating the most serious disorder first.

The conference thus provided new insight into the treatment of ADHD particularly considering the role of stimulant medications in young children. Decision to treat this age group with medications will depend on the severity and threat of the patient’s symptoms and the overall potential risks and benefits of medications. A combination of medications and behavioural therapy may be the most effective treatment.⁴ Monitoring of height, weight and cardiovascular effects is also essential. Hopefully armed with greater knowledge clinicians will be able to improve the quality of life of their ADHD sufferers and caregivers.

The 55th Annual Meeting of the AACAP is set to be held at Sheraton Chicago Hotel and Towers Cityfront Center, Chicago from October 28 to November 2, 2008. For further information and details of the 54th conference, please refer to the following website: http://www.aacap.org/cs/AnnualMeeting/2007

References:

1. American Academy of Child Adolescent Psychiatry, 54th Annual Meeting, 2007. Available [online] at URL http://www.aacap.org/cs/AnnualMeeting/2007
2. Kratochvil C, Greenhill L, Prince J, Walkup T, Robb A, Busch B, Harrison W. Practical Pediatric Psychopharmacology for the Primary Care Clinician (Pediatrician and Primary Care Institute – 27/10/07), AACAP Conference, Boston 2007.
3. Wilens T, Geller D, Solhkhah R, Findling R, Emslie G, DelBello M, Posey D. Advanced Psychopharmacology for Clinical Practice (Institute 1 – 23/10/07), AACAP Conference, Boston 2007.
4. Greenhill L. Efficacy and Safety of IR-MPH Treatment for Preschoolers with ADHD (Honours Presentation 4 – 23/10/07), AACAP Conference, Boston 2007.
5. Gleason M, Egger H, Greenhill L, Luby J, Scahill L, Wise B, Zeanah C. Preschool Psychopharmocology: Evidence and Perspectives (Institute 7 – 27/10/07), AACAP Conference, Boston 2007.