Inner trembling can have various causes, ranging in severity from 'needs attention' to 'very serious'. 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 inner trembling, we could:
Do you experience inner trembling?
Possible responses:→ No / don't know
→ Occasional / moderate
→ Often / severe