The Nature of Obsessive Compulsive Disorder: The Basic Phenomena

This is the first part of a series of blog posts that I will be writing regarding the nature of OCD. This first blog post aims to introduce the basics for those who are interested in learning some of the theory behind the phenomena. Please stay tuned for further updates regarding cognitive theories,  prevalence, what keeps OCD cycling, cognitive distortions and thinking errors, treatment options and relapse prevention.

A good understanding of the basic phenomena, to what obsessions are and the nature of how compulsions relate to obsessions is crucial for working effectively with service users with OCD. In my experience of offering training courses on OCD and working with this client group, there seems to be confusion over the basics, which is not exclusive to the general population, but also health care professionals. The following blog post aims to introduce the basics of OCD, the theories and provide examples of how it all fits together.


Obsessions are involuntary and often described as unwanted, intrusive thoughts, images, impulses or urges that are regarded as repugnant, senseless, unacceptable and very difficult to dismiss. Obsessions are accompanied by intense feelings of anxiety and discomfort, and an urge to ‘neutralise’ the thoughts (Salkovskis, 1999).

Intrusive thoughts have been researched extensively and regarded as universal, are experienced by those without a diagnosis of OCD or complaint of anxiety and are not thought to be problematic (Freeston et al., 1991; Rachman & de Silva, 1978; Salkovskis & Harrison, 1984). However, for those with OCD marked distress is common.

Rachman (2003) outlines the core, classical obsessions as aggressive/harm, sexual or blasphemous in nature and is common to experience more than one theme and explains how obsessions are regarded as ‘ego-dystonic’. This means that the obsessions are contrary to the person’s beliefs about themselves, their morals and what they find socially acceptable. It is understandable, knowing that obsessions are as far removed from the person’s own sense of being, that one might experience intense anxiety, and attempt to neutralise the intrusive thought or attempt to prevent the thought from entering one’s mind again.


Compulsions are voluntary, and often regarded as ‘neutralising’ behaviours that are carried out to offer temporary relief from the discomfort and anxiety caused by the obsession (Rachman, 2003). Although compulsions are seen as entirely voluntary behaviours, to the person experiencing obsessions the need to ‘neutralise’ is not seen as voluntary but vital to avoid catastrophic events or harm coming to self or others, or to minimise the impact of any obsessions they fear they might have carried out.

Compulsions can take the form of both overt (visible) and covert (unseen) behaviours, such as hand washing (overt) or mentally praying repetitively (covert) (Rachman, 2003). As overt rituals are easily seen, it is easier to recognise the possible symptoms, but for those who experience purely covert rituals it can be a little more difficult to detect.

There are two further forms of neutralising behaviours that are theorized. The concepts of Verification and Restitution has been widely discussed and researched. For people seeking verification, they may neutralise in order to prevent anything “bad” from happening, e.g. cleaning rituals to prevent cross contamination or spread of germs, or checking doors to ensure they are secure. Secondly, Restitution neutralising may be performed when one becomes convinced that something “bad” has already occurred or they fear they might have caused harm, and the neutralising behaviours take form to minimise its impact and put things right (Cougle et al, 2007).


Obsession: “I might not have turned the gas off properly, the house might blow up and I will lose all of my belongings, because of my carelessness”.

“If I don’t check the gas, it might be left on and I will be responsible for the house blowing up, and if people are in next door, they could be killed by my careless behaviour and I will go to prison”.

Compulsion: Repeatedly checking the gas hob or switch is off and checking the oven for the smell of gas (overt compulsions/rituals and verification).

Obsession: “What if I am potentially a psychopath and I might want to harm my own children”

Repetitive intrusive images of harming one’s own children.

Compulsion: Avoiding spending time with children or avoiding motherly/fatherly roles or hiding or eliminating objects that are potentially weapons from ones home e.g. sharp knives (this is a non exhaustive list of examples).

Obsession: “How do I know I haven’t put poison into my mum’s cup of tea?”

Compulsion: Pour the cup of tea down the sink and make a new cup (overt, restitution), or avoid making drinks altogether (covert).

The case of ‘false memories’

It is not uncommon for those who live with OCD to experience ‘false memories’. A false memory is an event that one might believe has took place, but is nothing but imaginational. False memories can seem very real and understandably can heighten anxiety. Needless to say, false memories cause anxiety because intrusive thoughts, images, impulse or urges are never pleasant in nature, and when one becomes frightened that they may have played out something heinous and terrible, it starts the process of restitution and reassurance seeking behaviours.


*Note to healthcare professionals – obsessions are ego-dystonic and not a true reflection of the person who experiences them and there has never been a single case of anyone undertaking any single obsession or intrusive thought. Obsessions are as far removed from the person’s morals and values that the mere thought of these creates intense anxiety and fear. People who experience intrusive thoughts/obsessions are not at any risk to harming themselves or others.


Cougle, J., R., Lee, H. and Salkovskis, P., M. (2007) “Are responsibility beliefs inflated in non-checking OCD patients?” Journal of Anxiety Disorders. 21 (1) pp. 153-159.

Freeston, M. H., Ladouceur, R., Thibodeau, N., & Gagnon, F. (1991). “Cognitive intrusions in a non-clinical population: I. Associations with depressive, anxious, and compulsive symptoms”. Behaviour Research and Therapy, 29, 585–597.

Rachman, S., & de Silva, P. (1978). “Abnormal and normal obsessions”. Behaviour Research and Therapy, 16, 233–248.

Rachman. S. (2003) The Treatment of Obsessions. Oxford: Oxford University Press

Salkovskis, P. M., & Harrison, J. (1984). “Abnormal and normal obsessions: A replication”. Behaviour Research and Therapy, 22, 549–552.

Salkovskis, P. m. (1999). “Understanding and Treating Obsessive Compulsive Disorder”. Behaviour and Research Therapy. 37, Supp. 1 S29-52