Attention-Deficit/Hyperactivity Disorder and Co-Occurring Tics

Attention-deficit/hyperactivity disorder (ADHD) and tic disorders often co-occur. They also often emerge during childhood. They are common, but general pediatricians who report competence in their clinical management of patients with ADHD are sometimes confused by lingering controversy over appropriate clinical management when these patients also have, or later develop, tics. Particular concern often stems from the apprehension that use of stimulant medications in treating ADHD will cause or exacerbate tics. Consequently, these children may not be adequately treated, jeopardizing optimal social and academic outcomes.

ADHD and tics: Clinical relationships

Jacob is an 8-year-old with ADHD-combined type diagnosed a year ago by his primary care provider. Since then, Jacob’s parents have opted to “wait and see” before starting any medication treatment. Beginning 1 month ago, Jacob began frequent eye blinking.

Tic disorders affect up to 20% of all children at some time.¹ For most such children, tics are mild in severity and simple in complexity (eg, isolated to muscle groups or body regions and appear not to mimic purposeful movements or spoken language). The tics often go unnoticed and resolve within a year of onset.

In contrast, chronic tic disorders, including chronic motor or vocal tic disorder and Tourette disorder (chronic motor and vocal tic disorder, also known as Tourette syndrome), last more than a year² and are less common, affecting about 1% of all children.³

Chronic tic disorders usually persist beyond the first decade and often into adulthood, customarily reaching peak clinical severity when the patient is aged between 10 and 12 years,⁴ with symptoms naturally waxing and waning over time. Chronic tics are often simple but may also be complex (Table 1).² All tics are stereotyped to the patient, which means that the affected person performs the tics again and again in a repeated, similar way.

ADHD and tics commonly co-occur

Children with ADHD are even more likely than unaffected children to have tics, and up to 20% of children diagnosed with ADHD will develop a chronic tic disorder.⁵ Conversely, half or more of children diagnosed with Tourette disorder are found also to have ADHD.⁶ Signs of ADHD typically emerge before the onset of tics. 

Although the respective diagnostic features of ADHD and tic disorders differ, there are some important overlapping phenomena that may help to explain their frequent co-occurrence and guide management. Most specifically, impulsive actions in ADHD (sudden and unpremeditated, unfiltered behaviors often prompted by a sense of urgency) and tics (sudden stereotyped movements or noises usually prompted by unpleasant warning sensations) may suggest a neural circuitry “disinhibition,” or release, of undesired patterns of behavior linked to emotion, sensation, movement, and cognition.

The physiologic model of disinhibition centers largely on dysfunction in monoamine neurotransmitter systems in communications among the basal ganglia, the frontal and other cortex regions, and the thalamus.⁷ The mechanism has not been fully characterized, but ongoing epidemiologic, pathophysiologic, and genetic investigations support the relationship between ADHD and tics, as well as other related neurodevelopment disorders of disinhibition including obsessions and compulsions, anxiety, and “rage” attacks.^7-9

Conditions associated with co-occurring ADHD and tics

Henry is an 11-year-old diagnosed with ADHD and Tourette disorder whose ADHD symptoms are treated with methylphenidate and behavior-management support. Henry has performed well academically and socially, but for the past 2 weeks, he refuses to go to school. His mother states that Henry seems unusually fretful and has become caught up in peculiar rituals, including “counting and checking everything” over and over.

Both ADHD and tics each place the affected children, adolescents, and adults at risk for psychosocial and neurodevelopment challenges.¹⁰ Most often, however, those with co-occurring ADHD and tics have greater functional and quality-of-life impairment than do those solely with tic disorders.¹¹ Therefore, clinicians must be alert to this heightened challenge and include a focus on ADHD when considering evaluation and management. 

Children with co-occurring ADHD and Tourette disorder show poorer social adaptation and are more likely to be bullied than those who have Tourette disorder alone and to have cognitive and other neuropsychiatric impairments.^12-15 Dual-affected children are more prone than children with Tourette disorder alone to have anxiety and depression and to display greater maladaptive behaviors, including aggression and delinquency.^9,16,17 In adolescence and continuing into adulthood, internalizing behaviors and disorders such as depression, anxiety, and social withdrawal predominate over externalizing behaviors, and obsessions and compulsive behaviors often emerge or intensify in both groups.^18,19

In addition, adults with co-occurring ADHD and Tourette disorder are more prone than those with Tourette disorder alone to maladaptive behaviors.¹⁸ Thus, because there are significant challenges when ADHD co-occurs with tics, clinicians should consider all potentially helpful avenues; 1 such avenue is stimulant medication.

Stimulant use in co-occurring ADHD and tics

Samantha is a 6-year-old diagnosed last month with ADHD, and shortly thereafter a low-dose trial of short-acting methylphenidate was begun. Within days, her mother and her kindergarten teacher noticed Samantha nodding her head repeatedly at irregular times. Samantha’s mother has heard from a neighbor that methylphenidate causes tics.

Historical concern

Families of children with co-occurring ADHD and tic disorders may have questions or strong concerns about psychotropic medications and about stimulant medications in particular. The popular lay and professional impression that stimulants cause or exacerbate tics is mostly untrue, and historical context along with recognition of some physiologic principles shed light on the basis of this misunderstanding.

Stimulants are believed to act beneficially in treating ADHD in large part by increasing dopamine activity, whereas excessive transmission of this monoamine is believed to cause or contribute to tics. Currently, the most effective medication treatments for reducing tics work by reducing the neurotransmission of the monoamine dopamine.⁵ Several uncontrolled case reports and case series in the 1960s to the early 1980s, generally based on retrospective chart reviews, noted associations of stimulant medication use and subsequent tic onset or exacerbation.^5,12 Ultimately, the US Food and Drug Administration (FDA) required that package inserts contraindicate the use of methylphenidate in patients with preexisting tic disorders or who have a family history of Tourette disorder, and for the use of amphetamines, a warning/precaution is provided.²⁰

Stimulants are unlikely to cause or exacerbate tics 

Beginning in the 1980s, a series of prospective studies adhering to rigorous, well-controlled, standard scientific design examined this issue. Despite the conventional and generally unchallenged assumptions of a stimulant-tic association, the results of these studies nearly universally failed to find a reliable association.²¹ These surprising findings ushered in our contemporary understanding that stimulants are very unlikely to evoke or exacerbate tics and are now a primary option in managing ADHD in patients with or predisposed to tic disorders. 

Evaluating ADHD in children with co-occurring tics

Gather information

Assessment for ADHD and tics is guided by careful attention to medical, neurodevelopment, and family histories; psychosocial influences, including parenting style, temperament, and academic performance; and completion of a physical examination, with heightened attention to neurologic elements. 

A standard approach to evaluation, diagnosis, and management is warranted in all children who are suspected to have ADHD whether co-occurring tics are present. The paradigm that ADHD is a diagnosis of exclusion holds: Carefully identify other potential sources of inattention, impulsivity, and hyperactivity that may mimic and/or exacerbate ADHD, including obsessions and compulsions, learning disabilities, anxiety, mood disorders, or somnolence.²²

Tic history

Any diagnostic uncertainty regarding tics requires appropriate evaluation to clarify. Many children and nearly all adolescents with tics can identify the presence of an involuntary, unpleasant, or distracting premonitory sensation that is unique to each tic type. This alerting sensory phenomenon is experienced as an urge and is specific to tics, often likened to a feeling of pressure, tension, or itch. The sensation is reduced or eliminated, temporarily, by committing the semivoluntary tic. The awareness of this sensation is virtually pathognomonic for tics. 

At the time of tic onset, it’s not possible to predict whether tics will follow a brief course (as is true for most children who develop tics) or will instead persist beyond 1 year to become a chronic tic disorder. Other unknowns include the anticipated complexity, interference, or number of eventual tic types. 

Particular attention to tics and their perceived influences on core features of ADHD behaviors is paramount. Frequent varied minor tics (eye blinking, shoulder shrugging, arm thrusting, or abdominal tensing) or bouts of a single tic type may be confused as fidgetiness or hyperactivity.²³ A child’s attempts to suppress tics can exacerbate ADHD symptoms by increasing emotional tension or by distracting the child.

When considering tics among children diagnosed with ADHD, determine who is raising behavioral concerns and delineate what his or her concerns are. The perspectives of the importance and interference of tic behaviors likely vary across social circumstances and across persons. Because media portrayals of Tourette disorder often feature only very severe, unflattering, or exaggerated clinical examples, it’s often useful to ask families about their understanding of tic disorders to ascertain any misconceptions or specific worries.

Comorbid conditions

Particular mention of obsessive-compulsive disorder (OCD) and related anxiety disorders is critical to understanding the clinical complexity of tic disorders in children. Although children with ADHD only are susceptible to anxiety disorders, those who also have co-occurring chronic tic disorders are much more highly susceptible to having OCD and may also be more susceptible to generalized anxiety disorder than those with ADHD only.¹⁶ To complicate matters, those who also have anxiety disorders are additionally at increased risk for depression. 

Clinicians should be aware of other frequent co-occurring conditions such as aggression, oppositional behavior, mood disorders,²² specific learning disabilities, and sleep disturbances, each of which may impart additional behavior and psychosocial burden and may aggravate or mimic signs and symptoms of ADHD and require appropriate screening, monitoring, and management.

Once a comprehensive evaluation has been completed and an initial determination of co-occurring conditions with other influences identified, priority in management usually should be directed to ADHD and, when present, to OCD and other anxiety disorders, rather than to tics. Effective treatments of these conditions may also secondarily reduce tic severity, because improvement in mental focus and attention may enable better social participation and reduced stress and less distraction or worry. At that point, tic severity can be reassessed.²² In rare exceptions, children whose tics cause intense interference or pain or that threaten self-injury require more immediate intervention targeting tic reduction. 

Managing ADHD in children with co-occurring tics

Family, education, and community focus

Early identification of tics among children with ADHD may provide the ounce of prevention needed to offset later diagnostic confusion, shame, or blame in child behavior. By providing accurate information, resources, and reassurance about tic disorders to families and by anticipating and responding to families’ questions or fears, clinicians often can then manage tics with families by monitoring the symptoms over time without more specific intervention.

Chronic tics naturally wax and wane over periods of minutes, days, weeks, and months, and their expressions are also heavily influenced by psychosocial stress, fatigue, prolonged attempts to suppress tics, and other variables. Anxiety states, in particular, frequently exacerbate tic severity. Although an initial comprehensive evaluation may not reveal other co-occurring behavior or development concerns, such conditions may evolve over time and should be monitored and screened periodically. 

Ideally, a family-centered management approach elicits prosocial communication and understanding among its members. Many neurodevelopment conditions are highly heritable, so that commonly 1 or both parents or siblings of affected children also have related neurodevelopment challenges.^18,24 Building positive parenting strategies that take into account surrounding impatience, anger, guilt, or misunderstanding may be central to effective management. 

The primary care provider can help to educate families regarding legally available accommodations to qualified children with ADHD or Tourette disorder whose conditions result in special education needs (via the Individuals with Disabilities Education Act) or restrict equal access within the public school (via Section 504 of the Rehabilitation Act).

Providers can and should encourage families to contact regional chapters of national agencies that are invested in supporting families and health care providers in their shared efforts to learn about ADHD and about tic disorders. In particular, the Tourette Syndrome Association (www.tsa-usa.org) and Children and Adults with Attention-Deficit/Hyperactivity Disorder (www.chadd.org) provide evidence-based information on issues of self-advocacy, special education, and medical care (Table 2).

Stimulants

A multimodal approach is optimal in the treatment of ADHD, and when inclusion of medication is indicated, psychostimulants have the proven best short-term efficacy.²⁵ Although data are less clear regarding which medications show superiority when ADHD co-occurs with tics,²¹ results from well-designed, placebo-controlled studies are clear that stimulant medications are unlikely either to exacerbate tics or to evoke tics among patients who are predisposed.²⁶

Families should understand that if they do observe tic severity to increase after initiation of stimulant medication, they could suspend medication use and consider reintroducing stimulants at a later time or consider alternative medication and other management strategies.¹²

Because the symptoms of ADHD are usually the most problematic, the priority will often begin with ADHD management.²¹ Methylphenidate has been investigated more closely than amphetamines in treating ADHD in patients with co-occurring tics, so it’s reasonable to consider methylphenidate first when choosing to use a stimulant medication in these patients. Advantages to stimulant medications include their fast-acting property and their superior profile in treating the core features of ADHD. There is some, albeit limited, evidence that stimulants may even modestly improve tic symptom severity and reduce oppositional behaviors, when such behaviors are part of the symptom profile.²¹

As a rule of thumb, begin with a low dose of a short-acting stimulant preparation. This approach reduces adverse-effect risks, allows more immediate discontinuation if necessary, and enhances titration control. Switch to a long-acting preparation if a stimulant proves effective and tolerable. If a stimulant proves ineffective and/or intolerable, consider a different stimulant (eg, amphetamine), an alternative class of medication, or the addition of an α2 adrenergic agonist. Care must be taken in using stimulants in patients with co-occurring anxiety disorders because stimulants can exacerbate anxiety, which can secondarily exacerbate tics.

Prescribing clinicians who recommend stimulants are obligated to provide families with a clear and reasonable response to the FDA contraindication to using stimulants in predisposed patients, as well as to discuss all other customary risks regarding the use of stimulants (eg, initial insomnia, appetite suppression, stomach upset, headache, dizziness). If medication is prescribed, routine cardiovascular, growth, and other customary monitoring are required.

Nonstimulant medication

Sometimes tics pose equal or more severe problems than do ADHD symptoms, particularly if tics are very frequent, embarrassing, or result in discomfort or (rarely) in mild self-injury. For such affected patients, the α2 adrenergic agonists clonidine and guanfacine may be preferred first agents. Their advantages to stimulants in these patients include more likely reduction in tics of mild to moderate severity as well as amelioration of hyperactivity and impulsive tendencies in ADHD. In addition, these agents can assist in reducing the difficulty with sleep initiation that frequently co-occurs in these children.²⁷

The addition of melatonin may further enhance sleep initiation. In contrast to the stimulants that take effect within hours or days of initiation, the beneficial effects of α2 adrenergic agonists generally take weeks before improvement is seen. Families should be alerted to this latency in effect to help them maintain compliance and reduce frustration.

The combined use of a stimulant and an α2 adrenergic agonist may also be considered, usually after 1 or both agents are first tried alone, to enhance likelihood of therapeutic effect. The combination is generally well tolerated.²⁶ An additional potential advantage is that when these agents are used together, their respective effects may help diminish each other’s adverse effects on states of insomnia/sedation.⁵ 

Although investigation of atomoxetine is very limited in this population, available good-quality evidence supports the selection of atomoxetine for patients among whom neither stimulants nor α2 adrenergic agonists, singly or in combination, prove satisfactory. Its potential benefits include improvement of ADHD symptoms and of tic symptoms, but further research is needed.²⁸

Desipramine also has undergone very limited investigation for this purpose but has been shown to be of possible benefit in treating both ADHD and tics.²⁹ However, because use of desipramine poses risk of serious cardiac effect, including sudden death, desipramine is not first-line treatment, and consulting with a child psychiatrist and/or completing a full cardiac workup is indicated before initiating this medication (Figure; Table 3).^5,30,31

Key treatment points to remember

Co-occurring ADHD and tic disorders, including Tourette disorder, are common. Both conditions place affected children at risk for challenges in emotional, behavioral, cognitive, and health functions, although effective ADHD management most often demands initial priority. Concerns about tic exacerbation from use of stimulant medication in patients with or at increased risk for tic disorders have proven largely unfounded.

Optimal ADHD management usually relies on inclusion of psychotropic medications, with educational and psychosocial support, and among medication options, the stimulants are usually well tolerated and most effective. Families should be appropriately informed of the limited relationship between stimulant medications and tics and that ongoing monitoring will be ensured. Patients with chronic tic disorders are also at increased risk to have or later develop anxiety disorders, including OCD. For these patients, nonstimulant medication options may target symptoms of anxiety, ADHD, and tics, as part of a comprehensive management approach.

References

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28. Spencer TJ, Sallee FR, Gilbert DL, et al. Atomoxetine treatment of ADHD in children with comorbid Tourette syndrome. J Atten Disord. 2008;11(4):470-481.

29. Spencer T, Biederman J, Coffey B, et al. A double-blind comparison of desipramine and placebo in children and adolescents with chronic tic disorder and comorbid attention-deficit/hyperactivity disorder. Arch Gen Psychiatry. 2002;59(7):649-656.

30. Roessner V, Plessen KJ, Rothenberger A, et al; ESSTS Guidelines Group. European clinical guidelines for Tourette syndrome and other tic disorders. Part II: pharmacological treatment. Eur Child Adolesc Psychiatry. 2011;20(4):173-196.

31. Scahill L, Erenberg G, Berlin CM Jr, et al; Tourette Syndrome Association Medical Advisory Board; Practice Committee. Contemporary assessment and pharmacotherapy of Tourette syndrome. NeuroRx. 2006;3(2):192-206.