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Everything You Need to Know About Obsessive-Compulsive Disorder

By Olivia Guy-Evans, published March 15, 2022

by Saul Mcleod, PhD

Obsessive-Compulsive Disorder infographic

What is obsessive-compulsive disorder?

Obsessive-compulsive disorder (OCD) is an anxiety disorder which is categorised by an individual experiencing obsessive thoughts (obsessions).

These obsessions are usually recurring and can be intrusive thoughts, ideas, or sensations. Because of these obsessions, this can drive an individual to perform certain actions, often repetitively to alleviate the anxiety that the obsessions have caused (compulsions).

OCD for many people could centre around certain themes such as fear of contamination, so they may excessively clean and hand wash. 

ocd anxiety cycle

A lot of people may experience obsessive and intrusive thoughts, however for OCD, these thoughts are persistent, and the behaviours displayed are rigid.

If the obsessive thoughts are ignored or the behaviours cannot be performed, this can result in increased anxiety and distress.

Therefore, OCD can significantly interfere with daily activities, normal functioning, and social interactions if left untreated. Often, the person with OCD may recognise that their obsessive thoughts aren’t true but will still have trouble disengaging from these thoughts or stopping the compulsive behaviours. 

OCD is thought to affect approximately 2-3% of the United States population and appears to be more common in women than men. The average age of the onset of OCD is 19 years old, but with 25% of the cases being recognised by the age of 14. 


Obsession thoughts in OCD often involve a feared outcome. Depending on the type of obsession experienced will depend on the feared outcome. For instance, someone may fear losing something important, fear upsetting someone, or fear for their and loved one’s safety.

These obsessions may become so overwhelming that it drives them to perform compulsive actions. These obsessions are often time-consuming and distressing to the individual, unwanted and are outside of the individual’s control.

Although many with OCD understand their thoughts are not realistic, they cannot be resolved by logic or reasoning. People may try to ease their distress by ignoring or suppressing their obsessions, or by distracting themselves, but often this can cause more unease and distress. 

types of ocd

Below are some types of obsessions in OCD that can be experienced through this condition:

  • Harm – individuals may have obsessive thoughts that they may harm themselves or others. This is not harm that is caused intentionally, but unintentionally through their own carelessness.

    Some of the obsessive thoughts could surround constant doubts that the doors in the house are locked. This type of obsession can result in compulsions such as checking, for instance, persistently checking that doors are locked or that the oven is turned off. 

  • Contamination – those with contamination obsessions will usually have an excessive fear of germs, dirt, and disease. They may fear being contaminated by other people or by the environment. They might have obsessive thoughts surrounding the fear of touching items others have touched. 

  • Physical illness – with this type of obsession, individuals have excessive worries about being ill. They may be hyperaware of their bodily processes such as breathing. These somatic obsessions can lead to obsessions related to illness, disease, or pain. 

  • Perfectionism - those who have obsessions surrounding perfectionism may be excessively concerned with exactness and symmetry.

    They may have worries about items which are not organised in a specific way or will perform compulsions in order for things to feel ‘just right’. This could also involve touching or tapping objects until a touch feels right to them. 

  • Superstitious beliefs – some individuals with OCD may have obsessions surrounding suspicions. This could be related to lucky or unlucky numbers, objects, colours, and words.

    Individuals may go to lengths to perform an action a certain number of times to their lucky number, e.g., switching on and off a light switch 7 times before leaving a room.

    Individuals may have strong worries around something they consider unlucky and try to avoid these as much as possible. 

  • Losing control – some individuals may have excessive obsessions about accidentally offending someone and performing impulsive acts such as insults, saying something forbidden, or stealing.

    They may have a lot of mental imagery which are aggressive or horrific in nature. They may have thoughts about shouting obscenities or acting inappropriately in public. Because of these thoughts, they may fear losing control of themselves. 

  • Religiosity – those with religious obsessions may have obsessive thoughts, worries, or concerns surrounding moral judgement. They may have excessive worries about offending religious entities. 

  • Unwanted sexual thoughts – individuals with OCD may have excessive obsessive thoughts surrounding intrusive or perverse sexual thoughts.

    These thoughts could be very distressing and relate to sexual aggression, inappropriate thoughts about children, or incest. 


Compulsions in OCD are the result of the obsessive thoughts. These can be repetitive behaviours or mental acts that individuals feel driven to perform in response to an obsession.

These compulsions are used to prevent or reduce the distress associated with the obsession. The compulsions could be constant repetition of an action, disrupt normal routine, or used to prevent something bad from happening according to the person with OCD.

These actions could be unrelated to the actual obsessions, and someone could repeat the compulsion so many times that they find themselves ‘stuck’ in the compulsions.

The individuals may make up their own rules to stick to or rituals they must perform. Compulsions often do not bring any pleasure, only offering temporary relief from anxiety. 

Some examples of compulsions include:

  • Washing and cleaning – e.g. excessive hand washing and cleaning of an object.

  • Checking – e.g. repeatedly checking the oven is switched off, doors are locked, switches are all turned off.

  • Orderliness – e.g. arranging items to face a certain way or wanting items to be placed in the same spot every time. 

  • Counting – e.g. this could be counting in patterns or to a certain number, counting how many steps are taken or tapping an item to a certain number. 


In order to be diagnosed with OCD, the symptoms must meet the criteria stated in the Diagnostic and Statistical Manual and Mental Disorders (DSM-5). 

The criteria states that there must be a presence of obsessions, compulsions, or both. Obsessions are defined by:

  1. Recurrent and persistent thoughts, urges, or images that are experienced, at some time during the disturbance, as intrusive, unwanted, and in most individuals, cause marked anxiety or distress. 

  2. The individual attempting to ignore or suppress these thoughts, urges, or images, or to neutralise them with some thought or actions (by performing a compulsion). 

Compulsions in the DSM-5 criteria are defined by:

  1. Repetitive behaviours or mental acts that the person feels driven to perform in response to an obsession, or according to the rules that must be applied rigidly. 

  2. These behaviours or mental acts are performed in order to prevent or reduce distress or preventing some dreaded event or situation. However, these behaviours or mental acts either are not connected in a realistic way with what they are designed to neutralise or prevent or are clearly excessive. 

To meet the criteria, the obsessions or compulsions have to be time consuming, such as taking more than one hour per day, or cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

Finally, for a diagnosis of OCD, the disturbances should not be better explained by other conditions such as generalised anxiety disorder or Autism.

The disturbances should also not be due to the direct physiological effects of a substance or a general medical condition. 

Causes and risk factors

A direct cause for the onset of OCD has not been found and the condition’s causes are not fully understood. There are however some theories for possible causes and possible risk factors which could make someone more likely to develop OCD. 

Genetic factors could be a potential cause for OCD. OCD appears to run in families, therefore those who have parents with this condition, are more at risk of developing OCD themselves. 

OCD could also be caused as a result of other mental health conditions experienced by the individual. Commonly, other conditions with a comorbidity of OCD are other anxiety disorders (e.g. generalised anxiety disorder, social anxiety), and mood disorders (e.g. major depressive disorder, bipolar disorder).

Some of the symptoms of OCD overlap with those of other conditions. For instance, the obsessive thoughts can be similar to the anxious thoughts of those with anxiety conditions, and the repetitive compulsive behaviours are alike to behaviours of those with tic disorders. It then makes sense to believe that these symptoms can elevate to a level where OCD is formed. 

Another possible cause of OCD is traumatic brain injury. Some cases have reported that there was noted acute onsets of OCD within a day to a few months following traumatic brain injury. Symptoms of OCD have also been associated with stroke lesions, brain tumours, and Parkinson’s Disease.

OCD appears to respond well to medication which affects the neurotransmitter serotonin (specifically selective serotonin reuptake inhibitors; SSRIs). Because of this, it has been suggested that serotonin levels and how the brain processes this chemical, is associated with OCD.

However, considering a lot of people with OCD also have other conditions alongside this, such as anxiety and mood disorders, it could be that the medication targeting serotonin is improving symptoms of those other conditions rather than OCD directly. 

Extreme stress can also be a contributor for the onset of OCD. The initial fear could arise from a stressful period of time, for instance losing a loved one, childbirth, serious illness, severe conflict.

The person may learn to avoid the fear associated with a certain situation by performing rituals to reduce the perceived risk that may no longer be present but is thought about a lot.

Since OCD could arise from extremely stressful situations, this could also relate it to posttraumatic stress disorder (PTSD), which could occur alongside OCD. 

It could also be that OCD is learnt. The obsessive fears and compulsions could be learnt from watching a family member with OCD or gradually learnt over time.

There may no always be a noticeable trigger which started the obsessions and compulsions, it could be a collection of small triggers over many years which further increase these symptoms until OCD is fully developed. 


Treatments for the symptoms of OCD depend upon the symptoms experienced and the extent that they affect the individual’s life and overall functioning. 

Psychotherapy, specifically cognitive behavioural therapy (CBT) is a popular treatment of OCD. Specifically for OCD, a type of CBT called exposure and response prevention (ERP) alongside cognitive therapy is most appropriate for the treatment of CBT.

ERP involves initially exposing the individual with OCD to situations or objects that trigger their fear and anxiety. They are then instructed to avoid performing their compulsions.

This will usually lead to increased levels of anxiety to begin with. By staying in a situation with heightened fear and without anything bad happening as a result (which is the obsessive fear of the individual), the individual with learn that their fearful thoughts are just thoughts rather than reality.

The aim is that over time and repeated exposure in later sessions, anxiety will decrease or even disappear. 

The cognitive therapy part of CBT helps the person with the way they think, feel, and behave. It encourages the individual to identify and re-evaluate their beliefs about the consequences of engaging or disengaging in compulsive behaviours.

A technique involves working with the therapist to examine the evidence that supports or does not support their obsessions. This can encourage the individual to view the situation more realistically and question whether their thoughts are real. 

Through CBT, people can learn that they can cope with their obsessions without relying on ritualistic and repetitive behaviours. A lot of people may be reluctant to begin participating in CBT due to the initial anxiety it evokes at the start, although over time, this anxiety should significantly decrease. 

Medication can also be an effective treatment for OCD. Specifically, selective serotonin reuptake inhibitors (SSRIs) which are a type of antidepressant. SSRIs work by blocking the reuptake of the neurotransmitter serotonin from being reabsorbed back into the presynaptic neuron which released it.

Through blocking this reuptake, this allows more serotonin to be circulating around the synaptic cleft, making it more likely that this chemical will reach the next neuron and have positive effects on the brain and mood. 

SSRIs are common among people with mood and anxiety disorders and some effectiveness has been shown with those who have OCD. Some examples of SSRIs are:

  • Sertraline (Zoloft)

  • Fluoxetine (Prozac) 

  • Paroextine (Paxil)

  • Escitalopram (Lexapro) 

Often, doctors may prescribe a higher dose of SSRIs to treat OCD, in comparison to mood disorders.

Typically, an improvement in symptoms relating to OCD can be seen after several weeks of taking the medication. It is usually recommended that those with more severe OCD symptoms receive a combination of CBT and medication to aid with their condition.

Do you need mental health help?


If you or a loved one are struggling with symptoms of an anxiety disorder, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline for information on support and treatment facilities in your area.



Contact the Samaritans for support and assistance from a trained counselor:; email [email protected].

Availiale 24 hours day, 365 days a year (this number is FREE to call):


Rethink Mental Illness:

0300 5000 927

About the Author

Olivia Guy-Evans obtained her undergraduate degree in Educational Psychology at Edge Hill University in 2015. She then received her master’s degree in Psychology of Education from the University of Bristol in 2019. Olivia has been working as a support worker for adults with learning disabilities in Bristol for the last four years.

Fact Checking
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How to reference this article:

Guy-Evans, O. (2022, March 15). Everything You Need to Know About Obsessive-Compulsive Disorder . Simply Psychology.

APA Style References

Substance, A., & Mental, H. S. A. (2016). Impact of the DSM-IV to DSM-5 Changes on the National Survey on Drug Use and Health.

Murphy, D. L., Timpano, K. R., Wheaton, M. G., Greenberg, B. D., & Miguel, E. C. (2010). Obsessive-compulsive disorder and its related disorders: a reappraisal of obsessive-compulsive spectrum concepts. Dialogues in clinical neuroscience, 12(2), 131. 

Mayo Clinic. (2020, March 11). Obsessive-compulsive disorder (OCD). 

Nichols, H. (2020, September 29). What is obsessive-compulsive disorder? Medical News Today. 

Deibler M. (2020, November 17). Obsessions in Obsessive-Compulsive Disorder (OCD). Very Well Mind. 

American Psychiatric Association. (2020, December). What Is Obsessive-Compulsive Disorder.

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