OCD and ADHD: How They Differ, How They Overlap and How They Are Treated

01OCD

What OCD is

OCD is characterised by obsessions, unwanted and distressing thoughts, images or urges, and compulsions, behaviours or mental acts repeated to neutralise the anxiety or prevent a feared outcome. Examples include fear of contamination with washing, doubts with checking, need for symmetry with ordering, and intrusive thoughts with mental reviewing or reassurance seeking. OCD can begin in childhood or adulthood. See OCD types and symptoms.

02ADHD

What ADHD is

ADHD is a neurodevelopmental condition with symptoms that start in childhood and persist across settings: inattention (losing things, forgetfulness, difficulty organising and finishing tasks), hyperactivity (restlessness) and impulsivity (interrupting, acting without thinking). In adults, hyperactivity often becomes inner restlessness. ADHD can be missed in girls and women; see ADHD symptoms in women.

03Differences

Key differences

• Why attention is lost: in OCD, obsessions and rituals take up mental space; in ADHD, attention drifts to whatever is more stimulating.
• Onset: ADHD symptoms are present from childhood; OCD can start at any age.
• Behaviour style: OCD tends toward caution, checking and avoiding risk; ADHD toward impulsivity and risk-taking.
• Experience of thoughts: obsessions feel intrusive and unwanted; ADHD thoughts are fast and scattered but not usually distressing in themselves.
• Repetition: compulsions follow rigid rules; ADHD routines are hard to maintain.
• Unfinished tasks: in OCD, because «it is never right»; in ADHD, because of distraction and poor planning.

04Overlap

Where they overlap

• Difficulty concentrating and completing tasks.
• Slowness at work or school.
• Hyperfocus in ADHD can resemble obsession; see ADHD hyperfixation.
• Anxiety is common in both; see anxiety and ADHD.
• Both involve differences in brain networks related to executive function and inhibition.

05Both

Having both OCD and ADHD

Research shows that OCD and ADHD occur together more often than expected by chance, particularly when OCD begins in childhood, and both are associated with tic disorders. People with both may experience a confusing mix: impulsivity alongside rigid rituals, distractibility alongside perfectionism. Having both is linked to earlier onset of OCD and more difficulty with daily functioning, so recognising both matters for treatment.

06Diagnosis

Why diagnosis is tricky

Inattention caused by obsessions can be mistaken for ADHD, and ADHD can be missed when OCD is more visible. A thorough assessment by a psychologist or psychiatrist looks at childhood history, school reports, the content of thoughts, the reasons behind behaviours and the context in which problems appear. Questionnaires help but do not replace a clinical interview. Other conditions, such as anxiety disorders, depression, autism and tic disorders, are also considered.

07Treatment

Treatment when both are present

• OCD: cognitive behavioural therapy with exposure and response prevention (ERP) is the first-line treatment; SSRIs are used when needed.
• ADHD: psychoeducation, organisational and time management strategies, coaching, and medication when appropriate; see managing ADHD without medication.
• Adapting therapy: ERP may need shorter, more structured sessions, reminders and external supports for someone with ADHD.
• Medication: stimulants usually help ADHD and are generally compatible with OCD treatment, but in some people they can increase anxiety or repetitive behaviours, so a specialist monitors the combination.
• Family and school support for children and teenagers.

09Daily life

Practical strategies for daily life

• Use external tools such as planners, phone reminders and checklists to manage ADHD-related forgetfulness, while agreeing with your therapist how to avoid turning checklists into compulsive checking.
• Break tasks into small steps with clear end points, which helps both perfectionism and procrastination.
• Set time limits for tasks that tend to become ritualised.
• Build regular exercise, sleep and meals into the week, which support attention and reduce anxiety.
• Tell family members how they can help without giving repeated reassurance.

10Summary

Key points to remember

• OCD and ADHD are different conditions that can look alike.
• The reason behind inattention helps tell them apart.
• They can coexist, and recognising both improves treatment.
• ERP for OCD and ADHD-focused strategies can be combined.