Diagnostic Overshadowing: When Other Conditions Hide Your ADHD

What is Diagnostic Overshadowing?

Diagnostic overshadowing occurs when healthcare professionals attribute your ADHD symptoms to another condition you already have - typically anxiety, depression, autism, or a personality disorder. Your ADHD goes undiagnosed because clinicians see what they expect to see.

This is extremely common. Research suggests that adults with ADHD wait an average of 12 years between first seeking help and receiving an ADHD diagnosis. During that time, they often receive multiple other diagnoses that partially explain their symptoms but miss the underlying ADHD.

How It Happens

Common overshadowing patterns:

• ADHD misread as anxiety: The constant worry about forgetting things, missing deadlines, and making mistakes looks like generalised anxiety. It is anxiety - but caused by ADHD, not existing independently.
• ADHD misread as depression: Years of underachieving, relationship failures, and feeling different leads to low mood. The depression is real but secondary to unmanaged ADHD.
• ADHD misread as bipolar: ADHD emotional dysregulation (intense highs when hyperfocused, crashes when bored) can look like mood cycling.
• ADHD masked by autism: AuDHD (co-occurring autism and ADHD) is common. If autism is diagnosed first, ADHD symptoms get attributed to autistic traits.
• ADHD misread as personality disorder: Emotional intensity, impulsivity, and relationship instability can be misattributed to borderline personality disorder.

Red Flags That Your ADHD May Be Overshadowed

• You have been treated for anxiety or depression for years but medication only partially helps
• Your symptoms started in childhood (ADHD) not adulthood (most anxiety/depression)
• You have a pattern of starting things enthusiastically then abandoning them
• You can hyperfocus for hours on interesting tasks but cannot focus at all on boring ones
• Time management, organisation, and working memory are lifelong struggles, not recent onset
• Stimulant medication or caffeine calms you down rather than making you anxious

What To Do About It

1. Request an ADHD-specific assessment. A general mental health assessment will not reliably catch ADHD. You need someone trained in adult ADHD - ideally a psychiatrist who specialises in it.

2. Bring your childhood history. ADHD is a neurodevelopmental condition present from childhood. School reports, childhood behaviour, family observations all strengthen the case.

3. Describe the pattern, not just the symptoms. Instead of saying "I am anxious," say "I have been anxious my whole life specifically about forgetting things, being late, and letting people down - and these things actually happen regularly because I genuinely cannot organise my time."

4. Ask about co-occurrence. ADHD commonly co-occurs with anxiety (50%), depression (30%), and autism (20-30%). Having one does not rule out the other. A good assessor will consider all possibilities.

Your Rights

You have the right to request a second opinion. You have the right to ask for an ADHD-specific assessment even if you already have other diagnoses. Under Right to Choose (England), you can choose your assessment provider. Under the Equality Act 2010, ADHD is a protected disability and you are entitled to reasonable adjustments.

If your current clinician dismisses ADHD because you already have another diagnosis, that is diagnostic overshadowing - and you can challenge it.