Diagnostic overshadowing, what it is and what to do

What diagnostic overshadowing is

Diagnostic overshadowing happens when a clinician sees a patient with a known diagnosis — depression, anxiety, autism, fibromyalgia, ME/CFS, chronic pain — and automatically attributes any new symptom to that condition without proper investigation.

Examples:

• A woman with anxiety reports chest pain. The GP says it's "just anxiety" and misses a cardiac arrhythmia.
• A man with schizophrenia reports stomach pain. The clinician says it's "psychosomatic" and misses appendicitis.
• A young person with autism has a seizure. It is written off as "behavioural" and epilepsy is not investigated.

It is one of the most dangerous forms of clinical bias because it stops investigation dead.

Who is most at risk

Diagnostic overshadowing disproportionately affects:

• People with learning disabilities — identified by the LeDeR programme as a major cause of premature death.
• People with mental health conditions — especially when reporting physical symptoms.
• People with chronic pain or fatigue conditions — new symptoms are often dismissed as "part of" fibromyalgia or ME/CFS.
• Women — especially with endometriosis, POTS, EDS, and MCAS, where symptoms are frequently attributed to anxiety.
• Older people — new symptoms attributed to "old age" rather than investigated.

How to spot it

Red flags:

• The clinician immediately links new symptoms to your existing diagnosis without asking follow-up questions.
• No examination or tests are offered for the new symptom.
• Your concern is dismissed with phrases like "it's just your anxiety" or "that's common with fibromyalgia."
• The symptom is getting worse but the clinician will not investigate further.
• You are told to "manage your stress" when you are reporting a clearly physical change.

How to challenge it

• Separate the symptoms. Say: "I understand my [existing condition] causes [symptom A]. This new symptom [symptom B] is different because [specific differences]. I would like it investigated separately."
• Ask for specific tests. "What test would rule out [serious condition] for this symptom?"
• Get it in writing. Ask the clinician to document in your record that they are attributing the new symptom to your existing condition and why.
• Bring an advocate. A witness or advocate makes dismissive behaviour less likely.
• Request a second opinion. If the clinician will not investigate, see someone else.

NHS guidance

Several NHS and GMC documents explicitly warn against diagnostic overshadowing:

• The NHS Long Term Plan commits to reducing health inequalities for people with learning disabilities, specifically citing diagnostic overshadowing.
• GMC Good Medical Practice requires doctors to treat patients as individuals and not make assumptions based on diagnosis.
• The LeDeR (Learning Disabilities Mortality Review) programme repeatedly identifies diagnostic overshadowing as a cause of avoidable death.

Citing this guidance makes it harder for a clinician to dismiss your concern without engagement.

When to escalate

Escalate if:

• A serious condition is missed because symptoms were attributed to an existing diagnosis.
• You suffer harm as a result (delayed treatment, progression of illness, unnecessary suffering).
• The pattern is repeated by multiple clinicians in the same practice or trust.

Start with a Stage 1 complaint. If harm is significant, contact a clinical negligence solicitor — diagnostic overshadowing is a recognised basis for claims.

Frequently asked questions