Medication
This page explains the main types of medication used for OCD and how they can reduce anxiety, based on current understanding.
However, before I start, I wish to put the disclaimer that I am not a medical professional. If you have any questions regarding medication, including whether you should take it or not, please see your doctor
There are three popular explanations for how medication works for OCD:
(a) Chemical Imbalance Theory
(b) Reduced Overall Tension
(c) Numbness Effect
(a) Chemical Imbalance Theory
The most common form of medication for OCD are Selective serotonin reuptake inhibitors (SSRIs).
Well‑known SSRIs include fluoxetine (Prozac), sertraline (Zoloft), citalopram (Celexa), and paroxetine (Paxil).
The general understanding is that anxious patients have a chemical imbalance, in particular, they don’t have enough serotonin
Let me explain this chemical imbalance theory and how medication is meant to help
Serotonin is one of the happy chemicals
For a person to be happy (and therefore not anxious), serotonin has to be spread to enough nerve cells in the brain.
The spreading of serotonin is meant to work like this. All nerve cells in the brain have a small gap between them. Certain nerve cells produce serotonin and want to pass it onto the nerve cells that need it. Those nerve cells that produce serotonin cannot directly give it to the other nerve cells.
Instead, they deposit the serotonin into the small gap between the nerve cells, and hope the nerve cells that need the serotonin just take it from this small gap. If the serotonin is not taken from that small gap, then the nerve cells that created it just take it back. So, the serotonin is not spread to the nerve cells that need it.
What SSRIs are meant to do is stop the nerve cells (that produce the serotonin) from taking it back. So, the serotonin sits in the small gap until the nerve cells that need it are ready to take it
This is the most common explanation for how SSRIs work. It dates back to the 1960s. However, when you dig deeper, you can find many flaws with this chemical imbalance theory. These include:
- When the medication is taken, the serotonin levels increase almost immediately, but the reduction in symptoms (anxiety, depression etc) can take up to two months to come through
- Many drugs that increase serotonin are wholly ineffective in treating anxiety and depression
The below articles in the 'Guardian' and ‘Psychology Today’ talk about this in more detail. Admittedly they concentrate more on depression than anxiety, but according to popular theory, both conditions stem from chemical imbalances, so what applies to depression can also apply to anxiety
Psychology Today article on serotonin
While the chemical imbalance theory is increasingly seen as outdated, SSRIs may still reduce anxiety in two ways: they lower the body’s overall tension, and for some people there is an additional numbness effect.
(b) Reduced Overall Tension
SSRIs help by reducing the body’s constant “on edge” state. When the body is running in a tense, reactive state, muscles stay tight, breathing becomes shallow, and the nervous system reacts to small things as if they’re threats.
By softening this physical stress response, SSRIs reduce the sense of being wound up or braced for danger. People often describe feeling less jumpy, less reactive, and less physically tense.
When SSRIs do help, virtually all patients experience this reduction in physical tension, and for most people this is the change that makes their anxiety feel less intense.
(c) Numbness Effect
SSRIs, and some other medications, can create a numb or emotionally blunted feeling. This doesn’t stop intrusive thoughts from appearing, but it reduces the emotional impact they have, leading to a noticeable drop in anxiety.
But this reduced anxiety comes at a cost — the same numbness that dulls fear and worry can also lessen positive emotions, making everyday experiences such as eating food less enjoyable.
I’ll explain the numbness effect in more detail by looking at how it appears across two Dose Durations — Partial Day Effect and Full Day Effect.
Partial Day Effect
For some patients, the numbing sensation lasts only part of the day. The medication produces a numbing sensation that typically lasts around 8 to 12 hours after each dose. For example, if a patient takes the medication at 9am, the numbing effect may continue until roughly 9pm the same day. After that point, as the sedative impact wears off, the protective effect disappears, and the OCD symptoms return to their usual intensity.
Even though this partial day sedation is often described as a side effect, for some patients it is actually the mechanism that makes the medication helpful, because during those hours the anxiety response is reduced.
However, the same numbing can also dampen positive emotions, making everyday pleasures like food less enjoyable.
Full Day Effect
For other patients, the numbing sensation extends across the entire day. This provides continuous reduction of anxiety, rather than limiting relief to an 8–12 hour window.
Another advantage of the full day effect is that, for some patients, the same dose provides stronger anxiety relief than the partial day Effect during the 8–12 hour window.
The trade off is that while this stronger and more persistent numbing provides greater anxiety relief, it also dulls positive experiences more than the partial day effect.
And just like the partial day effect, this continuous numbness is often described as a side effect, yet for certain patients it is the very reason the medication is effective, because it consistently reduces the anxiety.
To ease the dulling of positive experiences caused by numbness, short term therapy such as CBT can help reduce OCD anxiety within 3 to 12 months. Thus, patients may be able to lower their medication dose, lessening the numbness and regaining enjoyment of everyday activities. In some cases, therapy may reduce the anxiety enough for you to stop your medication altogether, and manage any remaining anxiety using techniques learned in therapy. Always speak to your doctor before reducing or stopping any medication.
My Personal Experience
I took SSRIs, and they did help me. In particular, they made my brain feel numb, which meant each OCD thought registered as less threatening. As a result, the anxiety these thoughts normally triggered was reduced.
This experience reflects what I described earlier as the numbness effect. The medication did not stop the intrusive thoughts themselves — they still appeared in my mind — but the emotional impact was blunted/reduced
Importantly, this numbness did not mean I lost the ability to think clearly or function in daily life. I could still use my intellect at work and remain fully aware in situations that required attention, such as crossing busy roads.
If your anxiety is severe enough, you should seriously consider taking them. When they work, they can reduce the anxiety significantly
SSRIs do have drawbacks, in the form of side-effects. When you first start taking them, it is common to get things like diarrhoea, headaches, feeling disorientated etc. These side effects tend to go by around two weeks for most people
Numbness can also appear when starting SSRIs. If this numbness disappears after the first couple of weeks, then it is simply a temporary side effect. However, if the numbness continues beyond that period, it is not a side effect — it is the very mechanism by which the medication reduces anxiety. For more detail, refer back to the Numbness Effect section.
Other Medications
If you are not prepared to take SSRIs due to their side-effects, there are two more medications that you can try
These are Pregabalin and Propranolol. They both have less side-effects compared to SSRIs, but the reduction in anxiety is also a lot less. I took Propranolol first, and the reduction in anxiety was around 2%. I stopped taking that and then tried Pregabalin, and the anxiety was reduced by around 3% to 4%. These medications did not help me significantly enough when I was taking them, so I ended up taking SSRIs. But it could be different for you
Short-Term Sedative Medications
When OCD first appears, the anxiety can be so overwhelming that doctors sometimes prescribe short-term sedative medications, such as Benzodiazepines. These provide almost immediate relief, and for some people, the medication is so effective that the anxiety from the intrusive thoughts goes completely.
Their calming effect often lasts somewhere in the range of 6 to 10 hours, depending on the specific medication and dose. However, they are strictly a temporary measure — usually prescribed for only a few days or weeks. This is because they can be highly addictive, and the medication often loses its effectiveness after two to four weeks. They serve as an "emergency bridge" to help you stabilize while waiting for long-term medications such as SSRIs to kick in, or for therapy to begin working.
Intrusive Thoughts and Medication
A common concern people have when taking antidepressants is whether they can cause intrusive thoughts.
No. They don’t create intrusive thoughts. OCD intrusive thoughts appear when the body is overwhelmed, mainly by stress or trauma.
Medication doesn’t add any new OCD thoughts. But in the first couple of weeks, antidepressants can briefly increase overall tension in the body, which can make existing OCD thoughts feel more intense. This settles as your body adjusts.
A related but different point is that medication also doesn’t remove intrusive thoughts. It reduces the anxiety attached to them, so the thoughts feel less intense — and for some people the difference is quite significant.
For a fuller explanation of how intrusive thoughts work, see this page.
Conclusion
Medication is best seen as a support tool. It can lower overall anxiety enough to make daily life and therapy easier — but it doesn’t address the root cause of OCD. That deeper change comes from addressing the life events that led to OCD in the first place.
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