What Are the 'Themes' of OCD? A Guide to Common Obsession Types (Contamination, Harm, & 'Pure-O')

When you hear OCD, what do you picture? For most people, it's a stereotyped image: someone washing their hands constantly or meticulously arranging items.

While these can be expressions of Obsessive-Compulsive Disorder (OCD), they are a tiny fraction of a much broader, more complex, and more painful reality. This stereotype is one of the cruellest parts of the disorder. It leaves millions of people suffering in silence, thinking, "My thoughts aren't about cleaning. They are about harm... or religion... or my relationship. This can't be OCD."

If you are trapped in a loop of terrifying, unwanted thoughts, the content of that thought is what we call an OCD theme.

These themes are not a reflection of your character, your desires, or your morality. They are simply the flavour of your OCD. They are the sticky, distressing topics that your anxious brain has latched onto. And no matter how dark or "unspeakable" your thoughts feel, you are not alone in them.

Understanding these themes is the first step in separating the disorder from the person. It's the first step in realising that you are not your thoughts.

The shame from OCD 'themes' (like harm or 'Pure-O') is often the most painful part of the disorder. You are not your thoughts.

What Is an OCD Theme?

An OCD theme is the specific subject matter of your intrusive thoughts (obsessions). Think of OCD as a bully that finds out what you care about most, and then attacks that very thing.

• If you value cleanliness and health, the theme might be Contamination.

• If you value kindness and safety, the theme might be Harm.

• If you value your partner, the theme might be Relationship OCD.

• If you value your faith, the theme might be Scrupulosity (also known as Religious OCD).

The theme is a disguise. The underlying mechanism is always the same: a terrifying "what if" thought (the obsession) that causes intense anxiety, followed by a ritual (the compulsion) to find certainty or relief.

Let's explore some of the most common and often misunderstood themes of OCD.

Theme 1: Contamination OCD

This is the most "famous" theme, but it's far more complex than just a fear of germs.

What are the obsessions? An intense, persistent fear of being "contaminated." This can be by germs, but also by:

• Body fluids, chemicals, dirt.

• "Bad" or "unlucky" words.

• Even the "essence" of a person you dislike.

What are the compulsions?

• Excessive hand washing, often to the point of raw, cracked skin.

• Ritualised showering (e.g., must be a certain length, or in a specific order).

• Compulsively cleaning household items, groceries, or mail.

• Avoiding "contaminated" places or people (e.g., public toilets, hospitals, parks).

• Asking others for reassurance (e.g., "Do you think that was clean?").

The fear isn't just about getting sick; it's often a magical fear of "feeling" contaminated forever, or of spreading that contamination and harming others.

Theme 2: Harm OCD

This is one of the most terrifying and shameful themes for sufferers, and one of the most misunderstood.

What are the obsessions? Unwanted, intrusive thoughts or "mental images" of causing harm to oneself or others. This can include:

• Fear of stabbing or harming a loved one (e.g., being near kitchen knives).

• Fear of pushing someone in front of a train or car.

• Fear of acting on a violent impulse.

• Fear of being responsible for a tragedy (e.g., "What if I hit someone with my car and didn't realise it?").

What are the compulsions?

• Avoidance: Hiding knives, avoiding loved ones, staying away from balconies or train platforms.

• Checking: Checking the news to make sure you didn't harm someone, driving back to check you didn't cause an accident.

• Mental Rituals: "Cancelling out" a bad thought with a "good" one, praying, or repeating a safe phrase.

• Reassurance-Seeking: Asking a partner, "You know I would never hurt you, right?"

It is critical to understand this: A person with Harm OCD is the least likely person to ever act on these thoughts. They are horrified by them precisely because they are so contrary to their actual values.

Theme 3: Checking & Responsibility OCD

This theme is driven by an inflated sense of responsibility and an intolerance of uncertainty.

What are the obsessions? A persistent, nagging doubt that you have failed to do something, leading to a fear of a catastrophic outcome.

• "Did I lock the door? What if someone breaks in and hurts my family?"

• "Did I turn the stove off? What if the house burns down?"

• "Did I make a mistake in that email? What if I get fired and ruin my family's life?"

What are the compulsions?

• Repetitive checking of locks, appliances, and light switches.

• Rereading emails hundreds of times before sending.

• Checking your body for signs of illness.

• Mentally "reviewing" your memory to be 100% certain you did the task.

• Taking photos of locked doors or turned-off stoves to "prove" it.

The problem is that the "checking" itself degrades your memory. The more you check, the less you trust your own memory, creating a vicious cycle of doubt.

Theme 4: Symmetry, Ordering, & "Just Right" OCD

This theme isn't always driven by a "fear" of a bad event, but by an intensely uncomfortable internal feeling that things are "not right."

What are the obsessions? A powerful, internal "urge" or "tension" that things must be perfectly symmetrical, ordered, balanced, or "even."

What are the compulsions?

• Arranging items on a desk or shelf until it feels "just right."

• Tapping one side of your body if you accidentally brushed the other side.

• Needing to re-write words or re-read sentences until the "feeling" is gone.

• Stepping in a way that feels "even" on both feet.

This is often one of the most time-consuming forms of OCD, as the person can get stuck in a ritual for hours, trying to achieve a feeling of completeness that never lasts.

Theme 5: Relationship OCD (ROCD) & Scrupulosity

These themes attack the very core of a person's value system: their relationships and their morals.

Relationship OCD (ROCD):

• Obsessions: "Do I really love my partner?" "Is this the 'right' relationship?" "Am I just 'settling'?" "Do I find that other person more attractive?"

• Compulsions: Constantly "checking" your feelings for your partner, comparing your relationship to others, seeking reassurance, or confessing every "doubtful" thought.

Scrupulosity (Religious/Moral OCD):

• Obsessions: "Did I commit a sin?" "Did I have a blasphemous thought?" "Am I a fundamentally bad, immoral person?"

• Compulsions: Excessive praying, repetitive confession, seeking reassurance from religious leaders, or avoiding religious services altogether for fear of having a "bad" thought.

The Most Confusing Theme: "Pure-O" (Purely Obsessional)

You may have heard of "Pure-O." Sufferers often use this term to describe having "only" obsessive thoughts, with no physical compulsions.

This is a misnomer. There is no such thing as "Pure-O."

A person with this theme is still performing compulsions, but they are hidden, mental compulsions.

What are the obsessions? Often existential, moral, or identity-based. "What if I'm a sociopath?" "What if I'm in the wrong sexuality?" "What is the meaning of life?" (asked not from curiosity, but from a place of intense, repetitive dread).

What are the compulsions? (The "Hidden" Rituals)

• Mental Reviewing: Ruminating or "analysing" the thought for hours, trying to "solve" it.

• Mental Reassurance: Repeating a "safe" phrase to yourself.

• Mental Checking: "Checking" your feelings or memories to prove the thought wrong.

• Avoidance: Pushing the thought away (which only makes it stronger).

"Pure-O" is one of the most insidious forms of OCD because the sufferer often doesn't even know they are performing compulsions. They just feel like they are going crazy in their own head.

Fictional Vignette

'James' was a devout Catholic and a loving husband. One day, while praying, he had an intrusive, blasphemous thought about a saint. He felt horrified. "Where did that come from?" He tried to "fix" it by repeating his prayer 10 times. Soon, he was spending an hour every night, stuck until his prayers felt perfect. At the same time, he found himself constantly testing his love for his wife. "Did I feel 100% love for her in that moment? What about when I saw that actress in a movie?" He would confess these doubts to his wife, who would reassure him, "Of course you love me." But the relief only lasted a few minutes. James was suffering from two separate themes (Scrupulosity and ROCD) that were being driven by the same underlying OCD mechanism: a demand for 100% certainty.

(This is a fictional vignette for illustrative purposes and does not represent a real client.)

OCD themes are just the 'flavour' of the disorder's noise. The content doesn't matter, and it doesn't define you. Therapy helps you untangle the thoughts and turn down the volume.

The First Step You Can Take Today: Name the Theme, Not the Thought

The content of your thought is a distraction. It's the "bully's" costume. The real enemy is the underlying process of OCD.

Your first step is to practice "de-fusing" from the content by labelling the theme.

When a terrifying thought pops into your head, instead of getting caught in the "what if" of the thought itself, try to mentally step back and label the process:

• Instead of: "Oh no, what if I didn't lock the door and..."

• Try: "This is a checking theme. I'm having a checking thought."

• Instead of: "I'm a terrible person for thinking that about..."

• Try: "This is a harm theme. My OCD is throwing a harmful thought at me."

• Instead of: "Do I really love them? What if I don't..."

• Try: "This is my ROCD theme acting up."

This simple act of "naming the theme" does two powerful things:

1. It creates a bit of space between "you" and "the thought."

2. It re-focuses you on the real problem (the OCD), not the "fake" problem (the content of the thought).

You are not a bad person. Your thoughts do not define you. You are a person with a clinical disorder, and that disorder has a name.

How Therapy at Shaw Psychology Can Help

No matter how weird or terrifying your theme is, we promise you, we have heard it before. Nothing you can say about your OCD thoughts will shock us or make us judge you.

At Shaw Psychology, our Melbourne-based clinical psychologists and counsellors see you as a person, not a set of symptoms. We understand that the content of your thoughts is causing you deep shame, but we also know that it is not you.

Our first step is to provide a safe and compassionate space to destigmatise these thoughts. We help you understand these themes are common, predictable patterns of a neurobiological disorder.

We then use the gold-standard treatment, Exposure and Response Prevention (ERP), to help you confront these themes, one by one.

• If you have a harm theme, we won't just tell you, "You're not a bad person." We will help you learn to hold a knife or sit with your child, and tolerate the anxiety without avoiding or performing a ritual.

• If you have a "Pure-O" theme, we will help you identify your mental compulsions and teach you how to drop the analysis and let the thought "be there" without engaging.

This process teaches your brain, on a deep and lasting level, that your thoughts are just thoughts - not threats.

Ready to Find Clarity?

Your theme is not a reflection of your character. It is a roadmap that shows us exactly where the OCD is attacking, and it gives us the exact targets for therapy. If you are tired of being bullied by your own thoughts, you don't have to fight this alone. Our team is here to help you understand the themes and break the cycle, for good.

Booking Link: https://links.shawpsychology.com/ocd-themes-spb