Contamination is the theme everyone pictures, which cuts both ways: it’s the one most likely to be recognised, and the one where the picture is most misleading. Plenty of people with severe contamination OCD don’t wash their hands unusually often, because their compulsions are avoidance and mental decontamination rather than washing.
The varieties
Germs and illness. The familiar version. Surfaces, bathrooms, hospitals, other people’s food, and a fear that’s usually less about getting sick yourself than about passing something to someone vulnerable.
Chemical and environmental. Cleaning products, asbestos, lead, pesticides, radiation. Often accompanied by extensive research, and often reinforced by the fact that these are genuinely hazardous in some doses, which makes the uncertainty feel legitimate.
Bodily fluids. Frequently overlapping with harm themes — a fear of transmitting something through blood, or of having contaminated someone else.
Emotional or mental contamination. The one that gets missed. Feeling contaminated by a person, a place, a memory, an idea, a word. Someone who feels dirty after contact with a specific relative, or after reading about something, and who showers for an hour without any germ being involved. There’s no physical agent, so nothing about it fits the stereotype.
The compulsions
Washing, obviously — but usually washing according to a rule: a duration, an order, a feeling of completion that must be reached. Cleaning. Changing clothes. Elaborate decontamination routines at the front door.
And then the invisible half: enormous avoidance, which is often the largest cost. Not visiting people. Not using public toilets, which shapes where you can go and for how long. Not letting anyone sit on the bed. Plus mental neutralising, asking whether something was clean, and researching transmission routes.
Treatment
ERP, graded from your own hierarchy. Touching what you avoid, and then not washing — which is the half that does the work. Typically: touch, then deliberately contaminate something you care about, then go about your day without decontaminating.
This is one of the themes where remote treatment is genuinely superior, because the exposures that matter are your own bathroom, your own kitchen, your own front door — and a clinician on video can be present for the real thing rather than a clinic approximation.
What about actual hygiene
A reasonable question and worth answering once. ERP doesn’t aim to make you unhygienic. The target is compulsive washing — washing driven by a feeling that must be resolved, performed to a rule, beyond what the situation calls for. Clinicians usually set an explicit normal standard together with you, so that the goal is defined in advance and not renegotiated during each exposure.
If you find yourself wanting to ask repeatedly where exactly that line is, notice what that asking is.