Answer
Yes. Tolerance and dependence can develop with prolonged uninterrupted oral use; persistent sleep problems should be medically assessed.
Sources for this answer
- Diphenhydramine Hydrochloride 25 mg Tablets 20's (P) (PL 43461/0065) — Current selected SmPCemc · Summary of Product Characteristics
- NHSNHS · NHS medicine guidance
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.