LITHIUM

Set to 2 different clues across 2 published puzzles, most often “Antidepressant medicine” — The New York Times, Sunday, 7 April 2002.

7 letters

Every clue on record, most used first

Antidepressant medicineonce
The New York Times — Sunday, 7 April 2002
Psychopharmacologist's prescriptiononce
The New York Times — Sunday, 5 September 1999