Adverse reactions to coffee can have various causes, ranging in severity from 'minor' to 'needs attention'. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose adverse reactions to coffee, we could:
How does coffee affect you? Adverse reactions include feeling 'wired', 'hyper' or jittery, nauseated or hungry.
Possible responses:→ I do very well on it
→ It seems to benefit me slightly
→ There is no particular effect / don't know
→ Occasional adverse reaction
→ Significant adverse reaction(s)