Why Isn't My Antidepressant Working?
An antidepressant may not work because the dose was too low, the trial was too short (most need 6 to 8 weeks at a therapeutic dose), the medication class was not right for your biology, or the diagnosis needs reassessment. Bipolar depression, untreated medical conditions, and substance use can all mimic treatment resistance. A psychiatrist can review whether your trials were adequate and whether the diagnosis is correct.
Key takeaways
- Most antidepressants need 6 to 8 weeks at a therapeutic dose to show full effect.
- An inadequate trial (too low a dose or too short) is not the same as a failed trial.
- Bipolar depression, thyroid conditions, and substance use can mimic treatment resistance.
- After two adequate trials, a psychiatrist may recommend TMS, SAINT®, or SPRAVATO®.
Common Reasons an Antidepressant Isn't Working
The most common reason is an inadequate trial: the dose was too low or the medication was stopped before 6 to 8 weeks. Other reasons include the wrong medication class for your biology, an incomplete diagnosis (such as bipolar depression misdiagnosed as unipolar), untreated medical conditions like hypothyroidism, and substance use. A psychiatrist reviews each of these before concluding a medication has truly failed.
Was Your Trial Adequate?
An adequate trial generally means taking an antidepressant at a therapeutic dose — not just a starting dose — consistently for 6 to 8 weeks. A medication stopped early because of side effects, or never increased beyond the starting dose, is usually considered an incomplete trial rather than a failed one. Reviewing pharmacy records with a psychiatrist is the first step.
Could the Diagnosis Be Different?
Depressive episodes in bipolar disorder often respond poorly to antidepressants alone and can be mistaken for resistant unipolar depression. Untreated comorbidities — anxiety, PTSD, ADHD, substance use — and medical conditions like hypothyroidism or sleep apnea can also produce the appearance of resistance. A careful reassessment sometimes changes the diagnosis or reveals a correctable cause.
What to Do Next
Ask your psychiatrist: Were my trials truly adequate? Should I try a different class or augmentation? Am I a candidate for TMS, SAINT®, or SPRAVATO®? What does my insurance cover?
Understanding SAINT® TMS: How It Works & What to Expect
SAINT® is an FDA-cleared treatment for adults with major depressive disorder who have not improved on antidepressants in the current episode. These videos explain how it works and how it differs from conventional TMS.
SAINT® is an FDA-cleared, fMRI-guided form of TMS developed at Stanford. Most patients complete treatment in one week — not the six weeks standard TMS requires.
Follow a real patient through the five-day SAINT® treatment week
Is SAINT® TMS Right for You?
Tried antidepressants without enough relief? SAINT® TMS is an FDA-cleared, fMRI-guided treatment for adults with major depressive disorder who have not improved enough with antidepressant medication.
SAINT® uses a personalized brain target and delivers treatment over five consecutive days. It differs from standard TMS in its targeting approach, treatment schedule, and research background. In a small randomized trial, 11 of 14 people receiving active treatment reached remission at the four-week assessment, compared with 2 of 15 receiving sham treatment. Results vary, and a five-day treatment course does not guarantee remission in five days.
How SAINT® Works and How It Differs From Conventional TMS
SAINT® is an FDA-cleared treatment for adults with major depressive disorder who have not improved on antidepressants in the current episode. This video explains how it works, and how it differs from conventional TMS.
Conventional TMS usually means about 30 visits over 6 to 9 weeks. SAINT is five visits over five days.
What makes it different: SAINT is the only FDA-cleared depression treatment that uses an fMRI scan to personalize the stimulation target to your individual brain. A 45-minute scan maps your brain and identifies the specific circuit linked to depression. Treatment is then delivered as ten 10-minute sessions per day, with 50-minute breaks between them, across five consecutive days.
In clinical trials, 79% of participants reached remission, with an average of 2.6 days to remission. SAINT is generally well tolerated; the most common side effects reported were mild headache and temporary scalp discomfort at the treatment site.
SAINT® at Neuro Wellness TMS Centers of America
Coral Springs, Florida
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Call or Text: 954-827-9793
Sources: Cole et al., American Journal of Psychiatry 2020;177:716-726 and 2022;179(2):132-141. magnusmedical.com/depression-therapy. PubMed 34711062. FDA 510(k) K220177.
Insurance coverage for SAINT is currently limited and varies by plan. Individual results may vary. This video is educational and is not medical advice. Talk to a qualified clinician about whether SAINT is appropriate for you. If you are in crisis, call or text 988.
Frequently Asked Questions
Why isn't my antidepressant working?
An antidepressant may not work because the dose was too low, the trial was too short (most need 6 to 8 weeks at a therapeutic dose), the medication class was not right for your biology, or the diagnosis needs reassessment. Bipolar depression, untreated medical conditions, and substance use can all mimic treatment resistance. A psychiatrist can review whether your trials were adequate and whether the diagnosis is correct.
How long should I give an antidepressant before deciding it isn't working?
Most antidepressants need 6 to 8 weeks at a therapeutic dose to show their full effect. Partial improvement at 4 weeks is common. If there is no improvement after 8 weeks at an adequate dose, or if side effects prevent reaching an adequate dose, a psychiatrist may recommend switching, augmenting, or trying a non-medication treatment.
Can depression become resistant to medication over time?
Depression can become less responsive to a medication that once worked — this is sometimes called tachyphylaxis or 'poop-out.' It can also recur after a period of remission. If a medication that previously worked stops working, a psychiatrist may adjust the dose, switch to a different medication, or add a non-medication treatment like TMS or SAINT®.
What are the signs of treatment-resistant depression?
The primary sign is persistent depressive symptoms after two or more adequate antidepressant trials. Other signs include partial response that plateaus, recurrent episodes despite medication, or side effects that prevent adequate dosing. A psychiatrist confirms the diagnosis by reviewing medication history, doses, durations, and screening for conditions that can mimic resistance.
Cited Research
SAINT® is delivered only by verified providers on the Magnus Medical system. Programs described as SAINT “alternatives”, “equivalents” or “fMRI-guided accelerated TMS” are not SAINT®, are not affiliated with us, and SAINT® results do not apply to them. Read our SAINT® disclaimer.
Have questions about whether TMS may be appropriate for you?
Speak with our clinical team. A free consultation is the best way to get answers specific to your situation.