Quick Answer
One of the reasons ketamine is used for treatment-resistant depression is its speed. Many patients notice some improvement within hours to days of the first dose, with cumulative effect over the induction phase. That's significantly faster than traditional antidepressants, which take 4 to 6 weeks. Sustained response usually requires the full induction series followed by maintenance dosing.
This question comes up frequently for patients researching ketamine therapy for depression at Good Health NC in Knightdale, NC.