What are the symptoms and treatment options for inattentive Attention Deficit Hyperactivity Disorder (ADHD)?

Symptoms of Inattentive ADHD

Inattentive ADHD is characterized by at least 6 symptoms of inattention that persist for at least 6 months, cause functional impairment across multiple settings, and were present before age 12. 1, 2

Core Diagnostic Symptoms

The following symptoms define the inattentive presentation and must include at least 6 of these manifestations 2:

• Lack of attention to details/careless mistakes in schoolwork, work, or other activities 2
• Difficulty sustaining attention in tasks or play activities 2
• Poor listening skills - appears not to listen when spoken to directly 2
• Failure to follow through on tasks - starts but doesn't finish schoolwork, chores, or workplace duties 2
• Poor organizational skills - difficulty organizing tasks and activities 2
• Avoidance of tasks requiring sustained mental effort - homework, paperwork, or prolonged concentration 2
• Frequently loses things necessary for tasks (school materials, tools, wallets, keys, phones) 2
• Easily distracted by extraneous stimuli or unrelated thoughts 2
• Forgetfulness in daily activities 2

Clinical Characteristics Distinguishing Inattentive Subtype

The inattentive subtype differs substantially from combined or hyperactive presentations 3:

• Later age of onset and referral compared to combined subtype 3
• Higher proportion of females affected relative to combined type 3
• Absence or minimal hyperactivity/impulsivity - this is the defining distinction 2, 3
• Much less likely to have oppositional defiant disorder or conduct disorder comorbidity 3
• More likely to be overlooked by professionals because externalizing behaviors are absent 3

Associated Functional Impairments

Beyond core symptoms, patients commonly experience 4:

• Academic underachievement despite adequate intelligence 4
• Low self-esteem from repeated failures 4
• Interpersonal difficulties in social and family relationships 4
• Overemotionality or overreactivity to situations 4
• Disorganization and forgetfulness causing problems at home, school, or work 2, 3

Diagnostic Pitfalls and Mimicking Conditions

Screen for comorbid and mimicking conditions before finalizing the diagnosis, as inattentive symptoms overlap substantially with other disorders 1:

• Depression and anxiety frequently present with inattention and may be primary rather than comorbid 1, 3
• Learning disabilities can cause apparent inattention due to academic struggles 1, 3
• Substance use (particularly marijuana in adolescents) mimics ADHD symptoms 1
• Sleep disorders (sleep apnea) cause daytime inattention 1
• Trauma/PTSD and toxic stress produce concentration difficulties 1

In adolescents specifically, symptoms must have been present before age 12 to meet DSM-5 criteria, requiring documented or reported early manifestations 1. Adolescents tend to minimize their own problematic behaviors, making collateral information from teachers, coaches, or family essential 1.

Treatment Approach

First-Line Pharmacotherapy

Stimulant medications (methylphenidate or amphetamines) are first-line treatment for inattentive ADHD, with 70-80% effectiveness rates. 5, 6

• Long-acting formulations are strongly preferred due to better adherence, consistent symptom control, and lower diversion risk 5
• Methylphenidate should be initiated at 0.5 mg/kg/day and titrated to target dose of 1.2 mg/kg/day (maximum 1.4 mg/kg/day or 100 mg) 2
• Amphetamines demonstrate superior efficacy in adults with larger effect sizes (SMD -0.79 vs -0.49 for methylphenidate) 5
• For adults over 70 kg, start at 40 mg daily and increase to 80 mg target dose after 3 days, with maximum 100 mg 2

Second-Line Non-Stimulant Options

When stimulants are contraindicated, not tolerated, or ineffective 5:

• Atomoxetine (only FDA-approved non-stimulant for adults): Start 40 mg daily, target 60-100 mg daily; requires 6-12 weeks for full effect with median response time of 3.7 weeks; effect size approximately 0.7 vs 1.0 for stimulants 5, 2
• Extended-release guanfacine or clonidine (alpha-2 agonists): Effect sizes around 0.7, useful as monotherapy or adjunctive with stimulants 5
• Bupropion: Particularly useful when depression is comorbid 5
• Viloxazine: Newer serotonin-norepinephrine modulating agent with favorable tolerability 5

Behavioral Interventions

Behavior therapy should be combined with medication for optimal outcomes 1:

• Parent training in behavior management using positive reinforcement, planned ignoring, and consistent consequences 1
• Behavioral classroom interventions to modify school environment 1
• Cognitive Behavioral Therapy (CBT) for adults, focusing on time management, organization, and planning skills - most effective when combined with medication 5

Critical Monitoring Parameters

• Blood pressure and pulse at baseline and each medication adjustment 5
• Height, weight, sleep, and appetite regularly during treatment 5
• Functional improvement across home, school, and social settings - not just symptom reduction 1
• Substance abuse screening before initiating stimulants in adolescents and adults 1
• Suicidality monitoring especially in first weeks of atomoxetine treatment (0.4% risk vs 0% placebo in pediatric trials) 2

Common Treatment Pitfalls to Avoid

• Do not prescribe stimulants "as needed" - ADHD requires consistent daily treatment for functional control across all settings 5
• Do not assume anxiety contraindicates stimulants - stimulants can improve executive function deficits that indirectly reduce anxiety 5
• Do not overlook comorbidities - majority of patients have another mental disorder requiring concurrent treatment 1
• Do not rely solely on patient self-report in adolescents/adults - obtain collateral information from family or close contacts 5