OCD intrusive thoughts: what is it and how is it treated?

Sufferers become very disturbed by thoughts of a harmful or sexual nature but can be helped by cognitive behavioural therapy

What is it?

Ruminative obsessive compulsive disorder – or OCD intrusive thoughts – is one of four types of OCD. According to the US National Institute of Mental Health, about 94 per cent of us have these thoughts, but it only becomes OCD when it is having a detrimental and distressing effect.

"We all have intrusive thoughts from time to time," says Dr Melanie Ryberg, a clinical psychologist working in Leinster. "Push someone off a cliff, hurt a baby, have sex with a relative: it's out of character, we didn't invite the thought and most of us can brush them off. But for people with ruminative OCD, they become disturbed by the thoughts because they take them to mean that something awful is true about who they are, and they get stuck in a cycle of being unable to function until they can be absolutely certain they are not the person their thought could imply. The anxiety arises when the thought itself is taken as evidence that it must be true."

Dr Fionnula MacLiam, who specialises in treating OCD, says she has catalogued 52 normal obsessive thoughts people have including breaking wind, vandalising and sex with an unacceptable person.

How does it manifest?

“People behave compulsively – reviewing things, trying to stop thoughts, seeking reassurance, avoiding situations – in an attempt to resolve the worry,” says Ryberg. “If, for instance, the intrusive thought is that they will harm children, they might avoid being around children. But it is ultimately self-defeating. If you ask people with this form of OCD whether trying to stop thoughts or avoiding situations makes them more or less anxious in the long run, they will consistently say that it makes them more anxious. This is because it reinforces the idea of being responsible for harm and only increases the intrusive thoughts. OCD masquerades as a friend and promises to keep you and other safe, but the cost is enormous. It takes over people’s lives.”


Dr MacLiam says that people with OCD intrusive thoughts should not be considered dangerous. “Because those thoughts are so repulsive to them, they have no desire to act on them.”

How common is it?

OCD itself is remarkably common. However, people who suffer from ruminative OCD may also have other forms of the condition, so statistics for ruminative OCD may not be reliable. A 2010 study from researchers at Harvard, the University of Pennsylvania and the University of Cape Town suggests that about 2.3 per cent of people will be diagnosed with OCD in their lifetime.

How is it treated?

Cognitive behavioural therapy is the treatment for ruminative OCD. This is an evidence-based treatment for many mental-health conditions including anxiety and depression, but is particularly valuable for OCD. Exposure therapy is a CBT tool where people are asked, with support, to engage in situations they might be avoiding and, despite anxiety, to stick with. “They realise that they won’t act on it,” says Ryberg. “It is remarkably effective. This condition can be treated and managed.”

Where can people get help?

The GP is the first port of call, who may refer them to the HSE mental-health service. Private treatment is also an option. Dr MacLiam advises sufferers to ensure their therapist is properly trained and accredited to provide CBT. For more information and support, see OCDIreland.org.

Read more: An OCD sufferer speaks out: 'What if I harm children?'                                           Obsessional intrusive thoughts: Scary secrets of the mind