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.
The medications used for OCD can be grouped by the balance they offer between anxiety reduction and possible side‑effects. This page outlines the main options, how they work, and what you can realistically expect from them.
SSRIs
The most common form of medication for OCD are selective serotonin reuptake inhibitors (SSRIs). These are considered the first‑line medication for OCD because they offer the best balance between anxiety reduction and possible side‑effects.
Well‑known SSRIs include fluoxetine (Prozac), sertraline (Zoloft), citalopram (Celexa), and paroxetine (Paxil).
There are three main explanations for how SSRIs are meant to reduce anxiety:
(1) Chemical Imbalance Theory
This theory claims that anxiety happens because the body doesn’t have enough serotonin overall.
According to this view, SSRIs are believed to help by increasing the overall amount of serotonin available in the body. The idea is that raising serotonin levels should reduce anxiety, because the anxiety is assumed to come from a deficiency.
This explanation became popular in the 1960s and was widely repeated for decades. 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While the chemical imbalance theory is increasingly seen as outdated, SSRIs are used to reduce anxiety in other ways.
(2) Reduced Overall Tension
OCD is caused by the body being in a long‑term high‑alert state. In this state the body isn’t resting properly because its normal threat‑detection system is more active than it needs to be, which creates physical tension such as muscle tightness and a feeling of pressure in the chest. When OCD shows up, it adds to this tension and makes the body feel even more on edge.
SSRIs help by lowering this underlying level of physical tension indirectly. They gradually reduce tension by dampening the brain circuits that keep the body in a high-alert state. SSRIs shift the entire threat processing network into a calmer mode, which includes the circuits involved in arousal, startle, and threat sensitivity.
When the body is less tense, intrusive thoughts and sensations feel less threatening because the body isn’t reacting to them with the same level of alarm. This reduced reactivity helps overall, but it’s most noticeable with OCD because OCD anxiety can be quite intense.
When SSRIs do help, virtually all patients experience this reduction in physical tension.
(3) Numbness Effect
SSRIs, and some other medications, can create a numb or emotionally blunted feeling. Not everyone experiences this effect, and for many patients it does not appear at all.
This numbness effect 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 occur because there is suddenly more serotonin available than the body is used to, which creates a brief chemical shock.
These side-effects tend to go by around two weeks for most people.
Alongside these short‑term physical effects, some people also notice changes in how emotions feel, in particular numbness.
Numbness can 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.
Clomipramine
Clomipramine is considered a second‑line medication for OCD.
It reduces OCD symptoms more strongly than SSRIs but it also causes more side-effects, which is why it’s usually tried only after SSRIs haven’t helped enough.
Even though Clomipramine indirectly increases serotonin, that increase isn’t what reduces anxiety. Like SSRIs, the actual reduction in anxiety comes from lowering the body’s background tension (see the ‘Reduced Overall Tension’ process described earlier), which makes intrusive thoughts feel less overwhelming. Some people also notice a numbness effect, which can make anxiety feel less sharp.
Other Medications
If you are not prepared to take SSRIs or Clomipramine 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.
The next page is on food - please click the button below