ADHD, Anxiety and Autism: Detecting Common Comorbidities

Is it ADHD, anxiety, autism or a combination?

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobiological disorder among children and adolescents. An estimated 9% of young people receive a diagnosis by the time they reach age 17 years. ADHD often coexists with anxiety disorder and/or autism spectrum disorder (ASD), as well as a range of other neurodevelopmental conditions and mood disorders. It can be a challenge to distinguish the symptoms of these comorbid conditions.

Review the following case study to determine your best course of action to diagnose and treat this young patient.

Case Study

Benji

7 years

Benji is a 7-year-old second grader whose mother brings him to your clinic because of school difficulties, emotional outbursts and increasing withdrawal from peers. His teacher describes him as bright but difficult to engage. The teacher reports that Benji regularly misses instructions, leaves work unfinished, talks out of turn and becomes upset when classroom routines change. At home, he often cries when he’s doing homework and recently told his mother, “I’m bad at everything.”

Which action is most appropriate as part of Benji’s initial evaluation?

Diagnose ADHD based on the teacher’s report and begin stimulant medication.

This answer is incorrect.

An initial pediatric ADHD evaluation should include information from caregivers, teachers and other relevant adults; evidence of functional impairment across settings; and screening for alternative or coexisting conditions such as anxiety, depression, learning disorders, sleep problems and neurodevelopmental disorders such as ASD.

Ask Benji’s mother whether Benji is inattentive, disorganized and forgetful at home, and diagnose ADHD if those symptoms are present at home and school.

This answer is incorrect.

Collect information from caregivers and school, assess functional impairment and screen for conditions that may mimic or coexist with ADHD.

This answer is correct.

Reassure the family that emotional outbursts are common at Benji’s age and schedule a routine follow-up.

This answer is incorrect.

Benji’s mother reports that he has always been sensitive to clothing tags and loud noises. He prefers the same morning routine, lines up his toys by color and talks at length about trains. He wants friends but often misses social cues and becomes confused when classmates change game rules. Over the past three months, he has also developed trouble falling asleep, often has stomachaches on school mornings and shows less interest in seeing a neighborhood friend.

Which of Benji’s symptoms most strongly suggests that ASD should be considered in addition to ADHD?

Difficulty completing independent schoolwork

This answer is incorrect.

Long-standing social communication differences, restricted interests, sensory sensitivities and distress with change are more consistent with ASD than ADHD alone. ADHD and ASD can co-occur, so clinicians should evaluate for both when symptoms support both conditions.

Interrupting during classroom instruction

This answer is incorrect.

Long-standing sensory sensitivities, restricted interests and difficulty with reciprocal peer interaction

This answer is correct.

Stomachaches in the morning before school

This answer is incorrect.

During the visit, Benji looks away when asked about school and says, “What if I mess up and everyone laughs?” His mother says he can stay focused for long periods when building train layouts at home, but he becomes distracted and upset during writing assignments and group activities at school.

Which follow-up question best helps distinguish anxiety-driven inattention from primary ADHD symptoms?

“Does Benji ever interrupt adults?”

This answer is incorrect.

Anxiety-related inattention often increases during unfamiliar, uncertain or performance-based situations and may improve when the child feels prepared or safe. ADHD-related inattention is usually broader and persists across preferred and nonpreferred activities, although symptoms may still vary by task demands.

“Does his attention improve when tasks are familiar, predictable or low-pressure?”

This answer is correct.

“Does Benji prefer trains over other toys?”

This answer is incorrect.

“How many minutes does homework take?”

This answer is incorrect.

Benji’s mother is most worried about his comment, “I’m bad at everything.” She says this began recently and occurs after homework or school complaints. Benji still enjoys trains and laughs with his cousin, but he has slept poorly and avoids school-related activities.

Which finding would most increase concern for comorbid depression rather than frustration related to ADHD, ASD or anxiety?

Brief self-critical statements only after difficult assignments

This answer is incorrect.

A sustained change related to persistent low mood or irritability, loss of interest, low energy and sleep or appetite changes warrants depression assessment. In children with ADHD or ASD, new withdrawal or hopeless statements should not be dismissed as only neurodevelopmental symptoms.

Persistent low mood or irritability with loss of interest, low energy and sleep or appetite changes

This answer is correct.

Refusal to wear clothing with tags

This answer is incorrect.

Becoming upset when the classroom schedule changes

This answer is incorrect.

As Benji’s health care provider, you are aware that ADHD, ASD, anxiety and depression can overlap and co-occur. Working with Benji’s parents, you develop a plan to gather parent and teacher rating scales, review sleep and learning concerns, and screen for anxiety and depression. You schedule a time to meet with Benji’s parents after the information is gathered and assessed.

Why it Matters

Accurate diagnosis helps primary care providers identify the causes of a child’s symptoms, avoid missed or unnecessary treatment, and coordinate supports for the child and family. Because ADHD often overlaps with anxiety, depression, ASD and learning concerns, careful evaluation can improve outcomes for children and families.

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