What Is Obsessive Compulsive Disorder?

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Obsessive-compulsive disorder (OCD) is a mental illness that can affect people of any age, gender or nationality. It is nothing to be ashamed of or embarrassed about. As the name suggests, the affected individual will suffer from obsessive thoughts and this will lead to compulsive behaviours. 

Symptoms usually start during puberty, but they can also first appear in childhood or adulthood.

According to NHS statistics, 12 out of 1000 people are affected by OCD in the UK, accounting for around 750,000 people. 


Obsessive-compulsive disorder is a mental disorder where the patient suffers from a cycle of obsessions and compulsions, which cause anxiety and distress. It affects around 2% of the population and it can lead to impairment in social or personal life.¹,²

Obsessions are persistent unwanted or intrusive thoughts and fears. For example, intrusive thoughts about contamination by germs, violent thoughts about self or others, and disturbing thoughts about sex or religion.

Compulsions are the behaviours that an individual feels the need to perform due to their obsessive thoughts, in attempt to relieve their anxiety. These can be mental or physical and include actions, such as, excessive hygiene measures, arranging things in a specified manner, repeatedly checking things and compulsive counting. While performing compulsions can relieve anxiety for a short time, in the long term, it leads to a vicious cycle.

OCD is ego-dystonic, meaning that the intrusive thoughts go against the individual’s true beliefs and values, and they are aware that their obsessive thoughts and compulsive actions are irrational.

Causes of obsessive compulsive disorder 

Scientists are still not sure what causes obsessive-compulsive disorder, but they suspect genetics and life experiences can both play a part. Brain scan shows increased activity in the areas of the brain dealing with strong emotions and their response. Serotonin, a chemical which helps in transmitting information from one part of the brain to another is found in abnormally low levels in OCD patients. These are a few factors that are suspected to cause OCD:

  • Genetics may contribute to OCD.
  • Research studies suggest that people who have first-degree relatives such as a parent, sibling or child suffering from obsessive-compulsive disorder are more likely to be affected. Also, if that relative suffered from OCD symptoms in childhood or teenage years, then the chances of developing the disorder are further increased. However, no specific “OCD gene” has been identified.
  • Brain abnormalities could result in OCD. Brain scans have shown some abnormalities in certain areas of the brain in people suffering from OCD. These changes are also observed in other brain disorders, such as, Parkinson's disease, Tourette syndrome and epilepsy. There is still not much research regarding how these abnormalities cause OCD symptoms in individuals.

There is still not much research regarding how these abnormalities cause OCD symptoms in individuals.

  • Stress may increase the chances of developing OCD or exacerbate symptoms. For example, in an individual who is genetically predisposed, stressful situations, such as bullying or abuse, may trigger OCD symptoms
  • PANDAS syndrome can cause OCD symptoms. PANDAS, which stands for Paediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections, is caused by the body's immune response to a streptococcal infection, such as strep throat, which mistakenly targets the brain. This autoimmune reaction can result in inflammation in areas of the brain responsible for behaviour and movement, leading to sudden onset of OCD symptoms and other neuropsychiatric issues in children

Signs and symptoms of obsessive compulsive disorder 

OCD symptoms include obsessions, in the form of intrusive thoughts, and compulsions repetitive behaviours. Everyone can experience intrusive thoughts, but if these thoughts are excessive, recurring and causing high levels of anxiety or interfering with daily life, they might be due to obsessive-compulsive disorder.²,⁶ 

Obsession symptoms

OCD obsessions are repeated, unwanted thoughts or urges, which cause anxiety and distress, often interfering with daily life.

Some of the obsessions are:

  • Fear of contaminating oneself or others
  • Fear that something bad will happen if a compulsion is not performed (e.g. “if I don’t line my books up perfectly, my child will die”)
  • Unpleasant and unwanted sexual intrusive thoughts
  • Fear of harming oneself or others
  • Excessive worrying about offending God
  • Excessive worrying about partners' flaws or qualities 
  • Excessive existential thoughts or worrying about death

Compulsion symptoms 

Compulsions are repetitive behaviours, which can give temporary relief from the anxiety caused by obsessions. Some common compulsions include:

  • Excessive hand washing 
  • Excessive cleaning of the house or objects 
  • Repeated tapping, touching or blinking
  • Checking doors repeatedly to make sure they are locked 
  • Checking appliances repeatedly to make sure they are switched off 
  • Performing tasks to make sure they end on specific 'safe' numbers 
  • Arranging products in a specified manner only 
  • Ruminating on a thought to work out whether it could be true
  • Seeking reassurance from others or from the internet

Management and treatment for obsessive compulsive disorder 

If you or anyone you know shows OCD symptoms, contact your GP. Without the correct treatment, symptoms might worsen. 

Your GP or healthcare provider might ask questions like 

  • Do you experience repetitive scary or unwanted thoughts?
  • Do you experience the urge to perform repetitive tasks or actions?
  • Do you frequently feel very anxious?
  • Do these symptoms interfere with your daily tasks?

OCD is classified into three levels depending on the severity of the symptoms.

  • Mild functional impairment: the symptoms are mild at this stage. Obsessive thoughts and compulsive behaviour take up around one hour of the day
  • Moderate functional impairment: the symptoms are moderate at this stage. Obsessive thoughts and compulsive behaviour consume around one to three hours of the day
  • Severe functional impairment: the symptoms are severe in this stage. They impact daily tasks to large a extent. Obsessive thoughts and compulsive behaviour consume more than three hours of the day

When OCD is confirmed, doctors might prescribe medications or therapy for relieving symptoms. If these don't work, transcranial magnetic stimulation (TMS) might be tried.¹,², ⁵,⁸

Therapies for OCD: There are various different types of therapies available for OCD treatment. A psychologist, or other mental health professional provides these psychotherapy sessions. 

  • Cognitive Behavioural Therapy (CBT): CBT can be helpful for patients with mild OCD symptoms. These sessions help the individual recognise and challenge negative thinking patterns. Gradually, through structured sessions, patients learn to recognise their irrational thoughts (cognitions) and begin to face their fears in a controlled manner (behavioural component)
  • Exposure and Response Prevention (ERP): is a form of cognitive-behavioural therapy specifically designed to treat OCD. ERP works by exposing patients to situations that trigger their obsessive thoughts and anxieties (exposure) and then helping them to refrain from engaging in their usual compulsive behaviours (response prevention). This process gradually reduces the anxiety associated with the obsessions and weakens the compulsive behaviour patterns. Over time, patients learn to tolerate the distress caused by their obsessive thoughts without resorting to compulsive actions, leading to a significant reduction in OCD symptoms
  • Acceptance and Commitment Therapy (ACT): treats OCD by helping patients to accept thoughts without judgement and without trying to eliminate them. Patients are encouraged to observe their thoughts mindfully and commit to actions that align with their core values. ACT helps individuals lead happy and fulfilled lives, despite the presence of intrusive thoughts

Medications for OCD: Antidepressants, usually selective serotonin reuptake inhibitors (SSRIs), can be beneficial for OCD patients too. These medications work by increasing levels of serotonin in the brain, thus relieving OCD symptoms in some patients. High doses of this medication are given to OCD patients compared to depression patients. These medications can take up to 12 weeks to show an effect.

Deep brain stimulation (DBS): Patients who are above 18 years of age, and don't respond to medications or therapy may be referred for DBS. In this, electrodes are implanted in certain areas of the brain. These electrodes deliver the targeted electrical impulses, which help in altering the abnormal impulses. 

This is a non-invasive treatment for patients that do not respond to medication or therapy. TMS uses magnetic fields to stimulate specific areas of the brain. During a TMS session, a magnetic coil is placed against the scalp, usually targeting the prefrontal cortex, an area involved in regulating mood and behaviour. The magnetic pulses induce electrical activity in the brain, helping to reset abnormal neural circuits associated with OCD.

DBS and TMS are complex procedures and they must be  discussed with the treating professional.


How is obsessive-compulsive disorder diagnosed? 

A GP or or other healthcare professional, will ask questions about symptoms and how much they affect daily life. If the initial screening questions suggest the patient may have OCD, the GP may refer the patient to a specialist, such as a psychiatrist or clinical psychologist. If the patient meets the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria for OCD, the mental health professional will make a diagnosis.

Can obsessive compulsive disorder be prevented? 

OCD can't be prevented, but early diagnosis and treatment can reduce the symptoms and improve the OCD patient’s quality of life. There are many therapies and medications available to reduce anxiety.

What is the difference between OCD and OCPD? 

Obsessive Compulsive Disorder (OCD) is a mental health condition where a patient suffers from unwanted, repetitive and intrusive thoughts and compulsions. OCD is ego dystonic, meaning that individuals with OCD are typically distressed by their symptoms and recognise them as irrational.

Obsessive Compulsive Personality Disorder (OCPD) is a personality disorder, which causes a chronic preoccupation with orderliness, perfectionism, and control, often without the presence of true obsessions or compulsions. OCPD is ego syntonic, meaning those with OCPD usually believe their need for order and control is justified and may not see it as problematic.

Who is are at risk of obsessive compulsive disorder? 

People whose first-degree relatives have OCD, especially those who developed symptoms in their childhood or teenage years, are at more risk of developing this disorder. Individuals who have suffered any abuse or trauma, especially in childhood, are also at a higher risk of developing OCD.

How common is obsessive compulsive disorder? 

According to the NHS statistics, every 12 out of 1000 people in the UK are affected by this disorder.

When should I see a doctor? 

If you feel you are suffering from OCD and the symptoms interfere  with your everyday tasks, it is recommended to see a doctor or mental health professional. 


Obsessive-compulsive disorder is a mental health disorder where an individual suffers from obsessions and compulsions. Obsessions are unwanted, repetitive or intrusive thoughts causing anxiety. Compulsions are the urges to perform any task caused due to obsessive thoughts. Sometimes, women or people assigned females at birth (AFAB) develop OCD symptoms during pregnancy or post-delivery (post-partum OCD). Common symptoms include intrusive, distressing thoughts about harm coming to the baby, such as fears of accidental injury or contamination.

Scientists are still researching the exact cause of this disorder, but stress, genetics, brain function and PANDAS syndrome are all potential causes of OCD symptoms.

There are three levels of this disorder depending on the severity of the OCD symptoms - mild, moderate and severe functional impairment. 

Psychotherapy and medications are the main treatment options available. Cognitive behavioural therapy, exposure and response prevention, and acceptance and commitment therapy can be beneficial. Antidepressant medications, such as serotonin reuptake inhibitors and selective serotonin reuptake inhibitors are given to patients in higher doses compared to depression patients. 

If these options don't work, then deep brain stimulation or transcranial magnetic stimulation can be tried.

There are many support groups available to help OCD patients such as OCD Action and OCD-UK. This disorder is nothing to be ashamed of. 


  1. Obsessive-compulsive disorder [Internet]. National Institute of Mental Health (NIMH). [cited 2023 Feb 11]. Available from: https://www.nimh.nih.gov/health/topics/obsessive-compulsive-disorder-ocd
  2. Murphy DL, Timpano KR, Wheaton MG, Greenberg BD, Miguel EC. Obsessive-compulsive disorder and its related disorders: a reappraisal of obsessive-compulsive spectrum concepts. Dialogues in Clinical Neuroscience [Internet]. 2010 Jun 30 [cited 2023 Jul 22];12(2):131–48. Available from: https://www.tandfonline.com/doi/full/10.31887/DCNS.2010.12.2/dmurphy
  3. Overview - Obsessive compulsive disorder (OCD) [Internet]. nhs.uk. 2021 [cited 2023 Feb 11]. Available from: https://www.nhs.uk/mental-health/conditions/obsessive-compulsive-disorder-ocd/overview/
  4. Obsessive-compulsive disorder (OCD) | royal college of psychiatrists [Internet]. www.rcpsych.ac.uk. [cited 2023 Feb 11]. Available from: https://www.rcpsych.ac.uk/mental-health/problems-disorders/obsessive-compulsive-disorder
  5. OCD (Obsessive-compulsive disorder): symptoms & treatment [Internet]. Cleveland Clinic. [cited 2023 Feb 11]. Available from: https://my.clevelandclinic.org/health/diseases/9490-ocd-obsessive-compulsive-disorder
  6. What is OCD? [Internet]. International OCD Foundation. [cited 2023 Feb 11]. Available from: https://iocdf.org/about-ocd/
  7. Obsessive compulsive personality disorder (OCPD) | ocd-uk [Internet]. [cited 2023 Feb 13]. Available from: https://www.ocduk.org/related-disorders/obsessive-compulsive-personality-disorder/
  8. Swierkosz-Lenart K, Dos Santos JFA, Elowe J, Clair AH, Bally JF, Riquier F, et al. Therapies for obsessive-compulsive disorder: Current state of the art and perspectives for approaching treatment-resistant patients. Frontiers in Psychiatry [Internet]. 2023 [cited 2023 Jul 26];14. Available from: https://www.frontiersin.org/articles/10.3389/fpsyt.2023.1065812

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Simmi Anand

B.Sc. Nuclear Medicine, Manipal University
MBA Healthcare Services, Sikkim Manipal University

An experienced Nuclear Medicine professional with a passion for writing.

She is experienced in dealing with patients suffering from different ailments, mostly cancer.

Simmi took a career break to raise her daughter with undivided attention.

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