ADHD and Comorbidities

No pediatrician thinks caring for children with attention-deficit/hyperactivity disorder (ADHD) is easy, but some of these patients are far easier than others! The difference between your patients with ADHD who give you nightmares and those you are eager to see at return visits is usually the presence of comorbidities (not counting parent issues!).

 

Comorbidities are very common with ADHD, occurring in nearly half of all patients. One of the tricky things about comorbidities in ADHD is that several of them, or medicines used to treat them, also are potential explanations for the ADHD symptoms themselves.

 

The most common comorbid conditions are learning disabilities, which are present in 12% when narrowly defined, but school underachievement occurs in up to 60% of children with ADHD. Children with learning difficulties that are not adequately accommodated can present with “ADHD symptoms.” These children can be inattentive, fidgety, or out of their seats; may do classwork slowly or poorly; and may ultimately be disruptive in class. What child wouldn’t act this way if he or she couldn’t understand the work? Remember that a child will do anything to “save face.” Acting up and getting sent out of class is a last resort, but not a bad option over being humiliated by looking dumb, being teased, or being embarrassed in front of peers.

 

Some clues that learning disabilities are responsible for symptoms include behaviors that occur selectively during specific subjects, reports of disliking the subject, or refusal to do homework for certain subjects. One would think that poor grades would point to learning disabilities, but this is not always true either because the teacher is not that discerning or because a bright child compensates while still struggling. Be sure to have some grade-level assessment you can administer yourself such as the Einstein Evaluation of School-Related Skills or the WRAT (Wide Range Achievement Test). A large proportion of children with ADHD have a reading disability so having standard paragraphs available is important in deciding who needs complete psychological testing.

 

With this high prevalence of reading disabilities, it should not surprise you that language disorders also are comorbid with ADHD, occurring in 4% of these children. Because language disorder is among the developmental issues most amenable to intervention, detection and referral are especially important. If a child does not answer your questions with the grammar, vocabulary, or flow of ideas you expect at a particular age, consider using the Sentence Repetition Test to check for understanding. There are no easy screens for the complex language expected of school-aged children, so consider referral to a speech-language pathologist if you are suspicious.

 

Anxiety is comorbid with ADHD in 21% of children, but most importantly, it the most-often-missed diagnosis causing ADHD symptoms. Consider anxiety when a child is too nervous to pay attention, is distracted by worry, is concerned about what peers think to the point of having to listen in on their conversations, is unable to come up with an answer for a teacher that is perceived as critical, or is perfectionistic about work so it never gets done on time. Although children with ADHD are rather poor observers of their own symptoms, I always ask, “Is it hard to pay attention in class?” and follow up on a “yes” by asking, “What is going through your mind when you are not paying attention?” Reports of daydreams about skateboarding are one thing, but if children say they are thinking about their mother or worrying about an upcoming test, then further evaluation for anxiety is in order. Using a screening self-report tool such as the SCARED (Screen for Childhood Anxiety and Related Disorders) or the Pediatric Anxiety Rating Scale have rather low sensitivity, but can help the conversation to define anxiety symptoms, something children do not find easy to do if asked directly.

 

Remember that anxiety disorders do not “fly alone” either: Children with one anxiety disorder have a greater than 60% chance of having two, and children with two have a 30% chance of having three or more anxiety disorders. That means that children with generalized anxiety disorder may well have obsessive-compulsive disorder or a specific phobia as well. Just watching for general worrying is not enough. Add to this that the parent coming in worried about their child may be the genetic source with an anxiety disorder themselves, potentially contributing to the child’s distress and making it harder for you to assess the severity of either the anxiety or the ADHD symptoms!

 

I am sometimes grateful that a child with ADHD has excessive anxiety because it may protect him from jumping out of windows! But the combination has downsides in making the child even less preferred by peers and more likely to have hostile bias attribution – the tendency to see others as a threat. This combination can result in impulsive proactive aggression. Recognizing the role of anxiety in the aggressive episodes, and helping the child and parent to identify it, also is crucial to successful management. Anxiety is rarely perceived by parents, teachers, or children themselves as a cause of oppositional or aggressive behavior, so you need to probe for this connection. There is no substitute for debriefing a specific example of aggression and asking the child, “What were you thinking right before this happened?” You may suspect anxiety simply by watching the child’s reaction to what the parent says in the interview. Having the child draw a picture of a child, tell a story about “What happens next?” and then “How does the story end?” can be another adjunct to detecting anxiety.

 

treatment for the ADHD may be Sometimes the treatment of ADHD makes the comorbid condition worse or vice versa. A prime example where treatment of one exacerbates the other is the use of stimulants, especially amphetamines, which can produce or worsen anxiety. Even though the reported side effects of stimulants do not state that there is more anxiety with amphetamines, I often prefer to prescribe dexmethylphenidate when both ADHD and anxiety coexist. The longer-acting preparations such as methylphenidate in a long-acting liquid or patch also seem to allow for finer tuning of dose with less anxiety exacerbation than shorter-acting preparations. Nonstimulants such as long-acting guanfacine or atomoxetine as a needed alone or in combination to allow a lower dose when the side effects of the stimulants on the anxiety outweigh their benefits. On the other hand, if the child is on selective serotonin reuptake inhibitors for anxiety (not the first-line treatment, which is cognitive-behavior therapy), he or she may experience behavioral activation that looks a lot like worsening ADHD!

 

Depression is “the other side” of anxiety – often developing at a later age after an earlier diagnosis of anxiety disorder – and another common comorbidity to ADHD occurring in 18% of children. Depression is less likely to masquerade as ADHD but still may present as inattention or poor performance. Remember that children with depression may act irritable or aggressive rather than lethargic. Depression screens such as the Patient Health Questionnaire–9 can help sort this out.

 

Oppositional-defiant disorder (32%) and conduct disorder (25%) are more commonly comorbid with ADHD than are the conditions just discussed, but because they are “acting-out” conditions they are of great concern to parents and thus not likely to be missed in your office visits. Other medical conditions such as tics, enuresis, encopresis and even asthma also are comorbid and should be asked about.

 

The Vanderbilt Initial questionnaires have a few items for anxiety, depression, and conduct as well as performance items about academic functioning. A general screening tool such as the Pediatric Symptom Checklist, perhaps followed by a diagnostic tool such as the CHADIS DSM questionnaire, can be completed by parents online or on paper to detect and help diagnose any of these comorbidities before visits.

 

Pediatricians are the main clinicians diagnosing (for 53% of children with ADHD) and managing this condition (Natl. Health Stat Report. 2015 Sep;81:1-8). You should be proud of how well we have recently risen to the occasion and are now identifying and treating ADHD using evidence-based tools (90%) and attempting to collect data from schools (82%) as well as parents. The biggest gap in effective primary care management of ADHD now is detecting and managing its comorbidities. 

 

Dr. Howard’s contribution to this publication is as a paid expert to Frontline Medical Communications. E-mail her at pdnews@frontlinemedcom.com.