What is Obsessive-Compulsive Disorder (OCD)?

Everything You Need to Know About Obsessive-Compulsive Disorder (OCD)

Obsessive-Compulsive Disorder infographic

What is OCD?

Obsessive-compulsive disorder (OCD) is an anxiety disorder that is categorized by an individual experiencing unwanted and intrusive thoughts (obsessions).

These obsessions are usually recurring and can be intrusive thoughts, ideas, or sensations. Because of these obsessions, they 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 center 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 behaviors displayed are rigid.

If the obsessive thoughts are ignored, or the behaviors cannot be performed, this can increase 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 recognize that their obsessive thoughts aren’t true but will still have trouble disengaging from these thoughts or stopping the compulsive behaviors.

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, with 25% of the cases being recognized 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 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 outside of the individual’s control.

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

types of ocd

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


Individuals may have obsessive thoughts about harming 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.


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.


Those with obsessions about perfectionism may be excessively concerned with exactness and symmetry.

They may worry about items that are not organized in a specific way or will perform compulsions 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, colors, 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 seven times before leaving a room.

Individuals may have strong worries about 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.


Those with religious obsessions may have obsessive thoughts, worries, or concerns surrounding moral judgment. 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.

Relationship OCD (ROCD)

Many of us occasionally experience varying levels of relationship anxiety.

However, for those with ROCD, these obsessions are all-consuming and uncontrollable and often get in the way of establishing and maintaining romantic relationships. 


Compulsions in OCD are the result of obsessive thoughts. These can be repetitive behaviors 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 the constant repetition of an action, disrupting the normal routine, or being used to prevent something bad from happening, according to the person with OCD.

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

The individuals may make up their own rules to stick to or rituals they must perform. Compulsions often do not bring pleasure, only 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, and 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 state 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 neutralize them with some thought or actions (by performing a compulsion).

Compulsions in the DSM-5 criteria are defined by:

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

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

To meet the criteria, the obsessions or compulsions must be time-consuming, such as taking more than one hour per day or causing 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 generalized 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 some theories for possible causes and risk factors that could make someone more likely to develop OCD.

Genetic factors could be a potential cause of OCD. OCD appears to run in families; therefore, those with 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 comorbidity of OCD are other anxiety disorders (e.g., generalized 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, obsessive thoughts can be similar to the anxious thoughts of those with anxiety conditions, and repetitive, compulsive behaviors are similar to behaviors 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 a traumatic brain injury. Some cases have reported an acute onset of OCD within a day to a few months following traumatic brain injury. Symptoms of OCD have also been associated with stroke lesions, brain tumors, and Parkinson’s Disease.

OCD appears to respond well to medication that 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 are 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 to the onset of OCD. The initial fear could arise from a stressful period of time, for instance, losing a loved one, childbirth, serious illness, or 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 to posttraumatic stress disorder (PTSD), which could occur alongside OCD.

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

There may not always be a noticeable trigger that started the obsessions and compulsions; it could be a collection of small triggers over many years that 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 behavioral therapy (CBT), is a popular treatment for 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 (which is the obsessive fear of the individual), the individual will 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 individuals to identify and re-evaluate their beliefs about the consequences of engaging or disengaging in compulsive behaviors.

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 to cope with their obsessions without relying on ritualistic and repetitive behaviors. Many 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) are a type of antidepressant. SSRIs work by blocking the reuptake of the neurotransmitter serotonin from reabsorbing back into the presynaptic neuron that released it.

Blocking this reuptake 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; some effectiveness has been shown with those with OCD. Some examples of SSRIs are:

  • Sertraline (Zoloft)

  • Fluoxetine (Prozac)

  • Paroxetine (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 support?


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: https://www.samaritans.org/; email jo@samaritans.org .

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


Rethink Mental Illness: rethink.org

0300 5000 927


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.

American Psychiatric Association. (2020, December). What Is Obsessive-Compulsive Disorder? https://www.psychiatry.org/patients-families/ocd/what-is-obsessive-compulsive-disorder

Saul Mcleod, PhD

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Educator, Researcher

Saul Mcleod, Ph.D., is a qualified psychology teacher with over 18 years experience of working in further and higher education.

Olivia Guy-Evans

Associate Editor for Simply Psychology

BSc (Hons), Psychology, MSc, Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.