This is general information, not medical advice, and every decision here belongs with a prescriber who knows your history. But there are two facts about OCD pharmacology that get missed constantly, and knowing them changes conversations.
Higher doses, longer wait
OCD typically responds to SSRI doses well above those used for depression — often at or near the top of the licensed range, and sometimes, under specialist supervision, above it. A dose that would be a solid antidepressant dose is frequently a subtherapeutic OCD dose.
And the timescale is longer. Depression may respond in four to six weeks; OCD often takes ten to twelve weeks at an adequate dose before the benefit is clear. An enormous number of people are told medication didn’t work for them when what happened was six weeks at half the dose.
If you take one thing from this page: ask your prescriber whether the dose and the trial length are adequate for OCD specifically.
What’s used
SSRIs are first line — fluoxetine, sertraline, fluvoxamine, paroxetine, escitalopram. Fluvoxamine and fluoxetine have the longest history here. Clomipramine, an older tricyclic, has strong evidence and is often effective when SSRIs aren’t, at the cost of more side effects and the need for monitoring.
For partial response, specialists sometimes add a low-dose antipsychotic as augmentation, which has reasonable evidence in treatment-resistant cases. That’s a specialist decision, not a routine one.
What it does and doesn’t do
Medication typically turns the volume down. Obsessions arrive less often and with less force; urges are easier to resist. What it doesn’t usually do is remove the disorder, and it doesn’t teach you anything.
ERP teaches. The combination is generally more effective than either alone, and for many people medication’s main value is making exposure work possible when the anxiety was previously too high to engage with it.
Two traps
Medication as a compulsion. Taking an extra dose during a spike, or checking repeatedly whether it’s working, or researching side effects for hours, turns the treatment into part of the loop. Worth naming with your prescriber if you notice it.
Stopping the moment things improve. Relapse rates on discontinuation are high, and higher if ERP was never done. The usual advice is to stay on it for a good while after remission and to taper slowly, with a plan — and people who have completed ERP tend to do considerably better when they come off.
Questions worth asking your prescriber
Is this dose in the range used for OCD rather than for depression? How long should we give it before deciding? If it doesn’t work, what is the next step — a different SSRI, clomipramine, or augmentation? And are you comfortable treating OCD specifically, or should I see someone who specialises?
That last question is fair to ask a GP, and a good one will answer it honestly.