Deciding on stimulant use for childhood ADHD

Attention deficit hyperactivity disorder (ADHD) is one of the most commonly investigated psychiatric disorders of childhood, and stimulants are among the most scrutinized evidence-based treatments. Controversy persists, however, about whether stimulants are appropriate and to what extent they should be used to treat problems of inattention and hyperactivity in children. Although detailed protocols are available to guide assessment and treatment of ADHD (eg, Dulcan,¹ American Academy of Pediatrics²), I argue there are 3 primary questions that can facilitate a decision about medication use for problems of inattention and hyperactivity and a clearer discourse on appropriate stimulant use for such problems.

Is the child functionally impaired?

A child suspected of having ADHD is typically identified by an adult, usually a parent or teacher. Physicians assessing these children must first determine whether the children are functionally impaired. Physicians must rule out the unreasonably high expectations of parents or teachers and determine whether children are functioning within normal limits given their developmental age. Without functional impairment, stimulants (or any other medications) are not indicated.

The main challenge is how to measure functional impairment. Ideally, functional impairment is established by systematically questioning at least 2 informants (typically parent and teacher) to determine function and dysfunction in a variety of settings (eg, home, school, community) and for a variety of tasks (eg, academic, interpersonal interaction, community participation). Unfortunately, there is a lack of user-friendly, validated instruments for measuring functional impairment in children with mental health problems (the new Brief Impairment Scale³ could be an exception, though it might still be difficult to implement in a busy practice). Ultimately, a threshold judgment is required to determine at what point dysfunction begins on a functional spectrum. Thresholds vary among individuals (eg, physicians, parents, teachers) and social groups (eg, North Americans versus Europeans or those oriented toward naturopathic approaches versus biomedical approaches) and might change over time. Tension arises when substantially different thresholds exist among different stakeholders (eg, physicians, parents, children, other family members, teachers).

If the child is functionally impaired, the second question is asked.

Do the ADHD symptoms cause the functional impairment?

Functional impairment determines the need for intervention but not the nature of that intervention. We must now determine whether a cluster of ADHD symptoms exists. Core ADHD symptoms are clearly identified in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).⁴ A variety of standardized instruments (such as the MTA-SNAP-IV, a short, free-for-clinical-use instrument that maps onto DSM-IV symptoms) completed by teachers and parents can help identify the presence of ADHD symptom clusters.⁵ The diagnostic thresholds proposed by DSM-IV (at least 6 of 9 symptoms from the inattentive items and/or the impulsive-hyperactive items), however, are not a determining point for treatment. If a child has only 5 symptoms but they are of sufficient severity to impair function, a medication trial might be warranted (diagnostically this is captured through the use of the DSM-IV category “ADHD—Not Otherwise Specified”). The important judgment is whether the cluster of ADHD symptoms contributes substantially, though not necessarily exclusively, to the functional impairment. This judgment could be corroborated by a stimulant trial, even though this might appear to contradict the typical caution to not use a stimulant trial to assist in ADHD diagnosis.⁶ Entertaining the notion of a stimulant-responsive behavioural disorder, as suggested by Dugdale,⁷ might be relevant here (ie, the goal in providing the stimulant is to improve the child’s behaviour and function, not to make a diagnosis).

Is a medication trial indicated?

Two factors need to be considered. First, is the functional impairment severe enough to warrant pharmacologic intervention? Second, are there contraindications to proceeding with a medication trial?

Whether there is sufficient functional impairment to justify medication is, again, a threshold judgment. There is no distinct point at which medication works and below which it does not. In addition, there appear to be few absolute contraindications to stimulant use. Rare medical conditions presenting with ADHD-like symptoms, such as hyperthyroidism, clearly require other medical interventions and can usually be differentiated by other concomitant symptoms. A history of severe adverse reaction to stimulants (or other medications under consideration) would obviously be a contraindication. Common psychiatric conditions comorbid with ADHD, such as oppositional defiant disorder and depressive disorders, do not contraindicate stimulant use. In general, it is prudent to address ADHD symptoms with a stimulant first in such comorbid cases, unless the child is in danger (eg, at risk of suicide) or the comorbid condition is much more severe than the ADHD. This is consistent with the general strategy outlined in the Texas Children’s Medication Algorithm Project for ADHD.⁸ This does not mean that stimulants are the only treatment that will be offered; however, there appears to be little reason to delay introduction of stimulant medication.

Comorbid bipolar disorder does not necessarily contraindicate a stimulant trial to treat ADHD. There continues to be controversy about the prevalence of bipolar disorder in children and about the extent of overlap or comorbidity with ADHD. Use of a stimulant to treat ADHD might be warranted, however, and might result in improvement among children with ADHD who have manic-like symptoms.^9,10 Use caution in cases of full bipolar disorder; stimulants might be more appropriately introduced after treatment with a mood stabilizer in such cases.¹¹ Specialist support would typically be needed for these complex cases.

Difficult psychosocial contexts also do not necessarily preclude the use of stimulants. For example, poor parenting practices should not prevent a stimulant trial if there are serious ADHD symptoms in the classroom, though such a case might entail making additional recommendations (eg, participation in a parent-training program). Caution and increased monitoring is suggested, however, when there is high risk of diversion (eg, youths selling their stimulant medication¹² or a family member with an active substance abuse problem).

The focus on medication in this article is not meant to minimize other evidence-based interventions for ADHD.¹³ Nevertheless, stimulant medication alone has been found to be less expensive and more effective than behavioural interventions alone on several outcome measures, and there is little evidence for greater effectiveness of combined treatment for ADHD.^14-16 Evidence-based behavioural interventions alone might be appropriate for mild or moderate ADHD, and they might be appropriate in combination with medication for children with complex and comorbid conditions.

A focus on thresholds is required to advance the important discourse on the extent of use of stimulants (and other medications) for ADHD. Increasing use of standardized instruments to measure ADHD symptoms and functional impairment in clinical practice might facilitate this discourse. Not only will this improve assessment and treatment practices, it will also indicate where we are currently setting our threshold for psychopharmacologic intervention. Unfortunately, primary care physicians often do not use standardized instruments, despite best-practice recommendations for their use for diagnostic assessment and determination of optimal dosing.^8,17 Innovations, such as the San Diego ADHD project, in which a centralized mechanism supports such data collection for a panel of primary care providers,¹⁸ could facilitate best practice and provide data to inform a productive discourse on thresholds.

Biography

Dr McLennan is a consulting child psychiatrist and Assistant Professor in the Departments of Community Health Sciences, Psychiatry, and Pediatrics at the University of Calgary in Alberta.