What Is OCD?
OCD, or Obsessive-Compulsive Disorder, is a mental health disorder marked by two key features:
Obsessions – Intrusive, unwanted thoughts, images, or urges that cause distress.
Compulsions – Repetitive behaviors or mental acts performed to reduce the distress caused by obsessions.
People with OCD often know that their thoughts and behaviors don’t make logical sense, but the anxiety they feel is so strong that it becomes difficult—if not impossible—to resist the urge to act on them.
What Are Ruminating Thoughts?
Rumination is a form of obsessive thinking that involves going over the same thoughts again and again, often trying to make sense of them or "solve" them. In OCD, ruminating thoughts might sound like:
“Did I lock the door? What if someone breaks in?”
“What if I accidentally hurt someone and didn’t realize it?”
“I need to remember exactly what I said—what if I offended them?”
Unlike regular worry, rumination in OCD isn’t productive. It doesn’t lead to resolution; instead, it intensifies anxiety and urges the person to keep thinking or checking in an endless loop.
What Sparks These Thought Loops?
The triggers for OCD and rumination vary from person to person, but common themes include:
Fear of harm – To self or others
Desire for certainty – The need to know something 100%
Moral or ethical concerns – Worries about being a “bad” person
Contamination fears – Germs, illness, or feeling "unclean"
These triggers create a spike in anxiety, which the brain tries to soothe by repeating a behavior or thought process. Over time, this creates a pattern: trigger → anxiety → compulsion/rumination → temporary relief → reinforcement of the cycle.
The Science Behind OCD and Rumination
OCD is thought to involve abnormal activity in a circuit of the brain that includes the orbitofrontal cortex, anterior cingulate cortex, and basal ganglia. These areas are involved in decision-making, error detection, and habit formation.
The orbitofrontal cortex signals when something is wrong.
The anterior cingulate cortex reacts with anxiety.
The basal ganglia helps initiate the behaviors that relieve the anxiety.
When this system is overly active or misfiring, the brain struggles to turn off the "alarm," even when there’s no real danger. This leads to persistent thoughts (obsessions) and repetitive behaviors or mental loops (compulsions and ruminations).
Additionally, OCD is associated with low levels of serotonin, a neurotransmitter that plays a role in mood regulation and anxiety. This is why many people with OCD benefit from selective serotonin reuptake inhibitors (SSRIs), which increase serotonin levels in the brain.
Why It’s So Hard to Stop
Many people with OCD say they know their fears are unlikely—but that knowledge doesn’t switch off the intense anxiety. That’s because OCD isn’t a problem of logic—it’s a problem of uncertainty intolerance. The brain keeps asking, "What if?" and refuses to accept anything less than complete certainty.
For example:
A person might think: "What if I hit someone with my car and didn’t notice?"
Their brain responds: "You better check, just in case."
They replay their drive over and over or even return to the scene.
This creates a powerful reinforcement loop. The temporary relief they get from checking confirms to the brain that the behavior was necessary—so the next time, the anxiety comes back stronger.
How OCD Is Treated
Fortunately, OCD is very treatable. The two most effective evidence-based approaches are:
Cognitive Behavioral Therapy (CBT), particularly Exposure and Response Prevention (ERP) – This involves gradually exposing a person to their feared thoughts or situations and preventing the compulsive response. Over time, this reduces the power of the obsession.
Medication – SSRIs such as fluoxetine (Prozac) or sertraline (Zoloft) can help regulate serotonin levels and reduce the intensity of obsessions and compulsions.
Takeaway: You’re Not Broken, and You’re Not Alone
If you find yourself stuck in ruminating thought loops or repetitive behaviors, you’re not weak or crazy—your brain is trying to protect you in the only way it knows how. OCD can feel exhausting and frustrating, but with the right support and treatment, it is possible to break free from the cycle.
Understanding the science behind OCD can help reduce shame and increase self-compassion. And the more we talk about it openly, the less power it has.
If any of this resonates with you, consider speaking to a mental health professional. Help is available, and healing is possible.