What is Obsessive Compulsive Disorder (OCD)?
What is Obsessive Compulsive Disorder (OCD)?
Obsessive-compulsive disorder is a mental health, anxiety-related condition characterised by a pattern of distressing thoughts and obsessive fears (obsessions) and mental acts that are compulsive, known as compulsive behaviours. According to OCDUK, OCD affects 1.2% of the population and affects over 1 million people every single day, significantly interfering with daily life while causing anxiety and distress.
OCD involves having unwanted intrusive thoughts and over actualised need to perform various repetitive behaviours and rituals to reduce the anxiety related to these thoughts. OCD seems to begin with misinterpreted thoughts. On average, think about 6,000 thoughts per day, some of which are unpleasant. Common obsessions occur when these thoughts are misinterpreted, making people anxious, which in turn causes them to occur more often and last longer.
People with OCD judge and monitor their thoughts, whether they are reasonable, bad, safe or dangerous. The thoughts are often perceived as harmful or threatening, and OCD can trick the body into reacting to these thoughts.
Read more about the Hidden Strengths of OCD.
Symptoms of OCD
Obsessive-compulsive disorder affects people in many ways, but usually causes a pattern of specific compulsive behaviours and thoughts. OCD symptoms often involve a cycle of distress, obsessions and compulsions. These are also recognised by the NHS as the three main elements of OCD.
Common symptom patterns can include obsession or fear of:
- Contamination, germs, dirt
- Harming someone
- Something bad happening
- Making mistakes
- Disturbing intrusive thoughts
While the symptoms of possible compulsion include:
- Washing, cleaning, avoiding touching things
- Checking doors, appliances, switches, and messages
- Avoiding people or objects, seeking reassurance
- Re-reading, redoing, asking others to confirm
- Arranging, counting, and repeating actions
- Mental checking, rumination, avoidance, reassurance-seeking
Types of Obsessions
In OCD, obsessions are recurring, unwanted thoughts, images, urges, doubts or worries that feel intrusive and cause distress. Themes vary widely, and a person can have more than one theme or see their themes change over time.
Common types of OCD obsessions include:
| Contamination fears |
| Harm obsessions |
| Checking or responsibility fears |
| Sexual intrusive thoughts |
| Religious or moral obsessions |
| Symmetry, order or “just right” obsessions. |
| Relationship obsessions |
| Health obsessions |
| Existential obsessions |
| Mental contamination |
Types of Compulsions
Compulsions are repetitive behaviours that people with OCD do as a way to reduce the distress caused by obsessions. People feel they must continue doing these actions and hope the distress will disappear. Compulsive behaviour can make you feel better at first, but when they become repetitive, the urge to do it again only gets stronger and can increase distress in the long term.
Compulsions are rules or rituals that people with OCD follow to help control anxiety when having obsessive thoughts.
The symptoms of compulsions vary and may entail:
| Constant checking |
| Repetitive counting |
| Repetitive hand washing and cleaning |
| Following strict routines |
| Requiring reassurance |
| Repeating words or phrases |
| Trying to replace negative thoughts with good thoughts |
| Arranging objects to face a certain way |
Difference Between Obsessions and Compulsions
Obsessions are the unwanted thoughts, images, urges, doubts or fears that repeatedly come into a person’s mind and cause distress. Compulsions are the behaviours or mental actions the person feels driven to do in response to the obsession, usually to reduce anxiety, feel certain, or prevent something bad from happening.
A simple way to remember it:
Obsession = the distressing “what if?”
Compulsion = the repeated “I need to do this to feel safe/certain.”
Here is an example of how it appears in daily life:
| Obsessions | Compulsions |
|---|---|
| Intrusive thoughts, images, urges or doubts | Repetitive behaviours or mental rituals |
| Usually feel unwanted and distressing | Usually done to reduce distress or gain certainty |
| Happen in the mind | Can be visible or hidden/mental |
| Example: “What if I left the oven on?” | Example: checking the oven repeatedly |
| Example: fear of contamination | Example: washing hands again and again |
| Example: intrusive fear of harming someone | Example: avoiding knives, mentally reviewing, seeking reassurance |
Types of OCD
OCD is usually one diagnosis, not several separate conditions. What people often call “types of OCD” are really themes: the subject matter of the obsessions and compulsions.
Common OCD themes include:
- “Pure O”/primarily obsessional OCD – A term some people use when compulsions are mostly hidden or mental, such as rumination, mental checking, neutralising thoughts or self-reassurance. Mind notes that compulsions can be mental as well as visible behaviours.
- Contamination OCD – Fears about germs, dirt, bodily fluids, chemicals, illness, or contaminating others. Compulsions may include washing, cleaning, avoidance or reassurance-seeking.
- Checking OCD – Fear that something has gone wrong or could go wrong, such as leaving doors unlocked, leaving appliances on, sending incorrect messages, or causing harm by mistake.
- Harm OCD – Intrusive fears or images about harming yourself or others, despite not wanting to. This can lead to avoidance, checking, reassurance-seeking or mental reviewing.
- Symmetry/ordering OCD – A need for things to feel even, exact, balanced, complete or “just right”. Compulsions may involve arranging, repeating or counting.
- Religious or moral OCD/scrupulosity – Fear of sinning, being immoral, offending God, lying, being a bad person, or not being morally pure enough.
- Sexual intrusive-thought OCD – Unwanted sexual thoughts, images, doubts or urges that feel distressing and out of line with the person’s values.
- Relationship OCD – Repeated doubts about whether you love someone, whether they love you, whether the relationship is right, or whether you are with the “right” person.
- Health OCD – Obsessive fear of having or developing an illness, often with checking, reassurance-seeking, body scanning or repeated research.
- Existential OCD – Distressing rumination about reality, death, consciousness, identity, meaning, or whether anything is “real”.
- Perinatal/postnatal OCD – OCD symptoms during pregnancy or after birth, often involving intrusive fears about harm, contamination, responsibility or the baby’s safety.
Causes of OCD
The exact causes of OCD are not fully known, yet it is generally described as one of the mental disorders that is likely to develop from a mixture of genetic, biological, psychological and life-experience factors, rather than from a single cause. Even though it is not known what causes OCD, several risk factors have been identified, including family history and genetic factors.
Other factors for developing OCD include:
- Brain and biological factors – Differences in brain activity or brain chemistry may play a role, though this does not mean there is a simple “brain cause” for everyone.
- Life experiences – Stressful or traumatic experiences, abuse, neglect, bereavement, bullying or major life changes may contribute to OCD developing or worsening in some people.
- Personality traits – Certain personality traits may increase vulnerability, such as being very anxious, highly responsible, perfectionistic, methodical, meticulous, or having very high personal standards.
- How a person responds to intrusive thoughts – Many people sometimes have strange or unwanted thoughts. OCD may develop when obsessive thoughts are seen as especially dangerous, meaningful or unacceptable, leading to compulsions, avoidance and reassurance-seeking.
People with OCD may feel ashamed, especially if their intrusive thoughts involve harm, sex, religion, morality or contamination.
OCD and Co-occurring Conditions
OCD can sometimes occur alongside other mental health or neurodevelopmental conditions, which can shape how symptoms appear and how they affect daily life. These overlaps may influence diagnosis, treatment plan, and the type of support a person needs. Below, we explore how OCD can interact with ADHD, autism, depression, anxiety, and eating disorders.
OCD and ADHD
OCD and ADHD can co-occur, although they often affect attention and behaviour in different ways. ADHD may involve distractibility, impulsivity and difficulty staying organised, while OCD is usually driven by intrusive thoughts and compulsive behaviours aimed at reducing anxiety. When both are present, a person may feel caught between racing attention, mental restlessness and time-consuming rituals, making diagnosis and support more complex.
OCD and Autism
OCD and autism can sometimes appear similar because both may involve repetition, routines and strong preferences for predictability. However, OCD compulsions are typically performed to reduce distress caused by intrusive thoughts, while autistic routines or repetitive behaviours may be linked to comfort, regulation, sensory needs or enjoyment. Understanding the difference is important so that support is tailored to the person’s experience rather than focusing only on outward behaviours.
OCD and Depression/Anxiety
OCD commonly occurs alongside depression and anxiety, as ongoing intrusive thoughts and compulsions can become emotionally exhausting. Anxiety may intensify obsessions and avoidance, while depression can develop when OCD begins to interfere with relationships, work, study or daily life. When these conditions overlap, treatment often needs to address both the OCD cycle and the wider impact on mood, confidence and wellbeing.
OCD and Eating Disorders
OCD and eating disorders can overlap when intrusive fears, rigid rules, perfectionism or compulsive rituals become connected to food, body image, exercise or control. For some people, checking, counting, reassurance-seeking or avoidance may form part of both conditions, making symptoms harder to separate. Recognising this overlap can help ensure support addresses not only eating behaviours, but also the anxiety, compulsions and beliefs that may be maintaining them.
Treatment Options for OCD
OCD treatment usually centres on CBT with ERP, medication such as SSRIs, or a combination of both. For people who do not respond to first-line support, options may include more intensive CBT, clomipramine, specialist OCD services, inpatient care in severe cases, or newer specialist approaches such as I-CBT.
One of the most practised treatments that a mental health professional can suggest for treating OCD may include:
- CBT with Exposure and Response Prevention (ERP) – This is the main psychological treatment recommended for OCD. It helps people face trigger obsessions gradually while reducing compulsions, avoidance, checking, reassurance-seeking or mental rituals.
- Low-intensity CBT with ERP/guided self-help – For milder OCD, UK guidance often starts with lower-intensity CBT, which may involve structured self-help, brief therapist support or group-based approaches.
- More intensive CBT with ERP – NICE guidance allows more intensive CBT with ERP, usually more than 10 therapist-hours, when lower-intensity support is not enough or symptoms cause greater impairment. OCD-UK’s NICE treatment summary says people with more severe OCD should be offered either an SSRI or more than 10 hours of CBT with ERP.
- SSRIs – SSRIs are commonly prescribed for OCD in the UK, often through GP or specialist mental health services depending on age, severity and risk.
- Combined CBT with ERP and SSRI medication – For more severe OCD, UK guidance supports combining CBT with ERP and an SSRI.
Read more about how to live well with OCD, in which we share self-care tips for an improved life.
How to Get Help for OCD in the UK
If you think you may have OCD, a good first step is to speak to your GP. They can talk through your symptoms, how they are affecting your day-to-day life, and refer you for appropriate NHS support. Adults can also self-refer to NHS Talking Therapies for anxiety and depression, where support may include CBT, guided self-help or other talking therapies depending on local services.
You can find your local service here: Find NHS Talking Therapies.
NHS England also confirms that people can refer themselves or be referred by a healthcare professional.
If symptoms are complex, severe, or have not improved with standard treatment, you may be able to ask your GP, therapist or mental health team about referral to a specialist OCD service. OCD-UK explains that NHS specialist OCD treatment services are available in England and are provided by clinicians with expertise in OCD treatment and research. You can read more here: OCD-UK: NHS specialist OCD treatment services.
Online support groups can be a helpful way to connect with others who understand OCD, share experiences, and feel less alone while seeking or continuing treatment. OCD Action runs peer-led online support groups for people in the UK affected by OCD or related conditions, including groups for parents, carers, partners and loved ones, with access via Zoom and some phone support options. You can find them here: OCD Action Online Support Groups. OCD-UK also runs free online OCD support groups via Zoom, facilitated by staff and volunteers with lived experience. These groups focus on sharing experiences and recovery-focused ideas and are available to people across the UK. You can find them here: OCD-UK Online Support Groups.
How OCD is Diagnosed in the UK
OCD is diagnosed in the UK through a clinical assessment that identifies obsessions, compulsions, distress and impact on daily functioning. The assessment can be done with a GP, a mental health professional, a psychologist, or a psychiatrist.
The assessment looks at whether a person experiences obsessions — unwanted, intrusive thoughts, images, urges or doubts — and compulsions, such as checking, cleaning, reassurance-seeking, counting, avoidance or mental rituals. A clinician will also ask how much distress these symptoms cause, how much time they take up, and how they affect daily life, work, school, relationships and wellbeing.
Assessing the level of distress and functional impairment as mild, moderate, or severe helps guide the next steps for treatment.
Myths and Misconceptions
There are many myths and misconceptions circulating about OCD, which make it harder for people to recognise symptoms, seek support or feel understood. OCD is often reduced to cleanliness, tidiness or perfectionism, but in reality, it is a complex mental health condition involving unwanted thoughts, distress and compulsive behaviours. The table below explains some of the most common misunderstanding aout OCD and what they really mean.
| Myth or misconception | Reality |
|---|---|
| OCD is just being very clean or tidy | OCD is not simply liking cleanliness or order. It involves intrusive thoughts, intense distress and compulsive behaviours that can feel difficult to control. |
| Everyone is “a bit OCD” | OCD is a recognised mental health condition. Many people enjoy routines or organisation, but OCD causes significant distress and can interfere with daily life. |
| OCD is always about germs or contamination | Contamination fears are one type of OCD, but OCD can also involve fears around harm, relationships, religion, sexuality, symmetry, responsibility, health, morality or intrusive images and urges. |
| People with OCD just need to stop doing rituals | Compulsions are often driven by overwhelming anxiety or fear. Recovery usually requires structured support, such as CBT with Exposure and Response Prevention, rather than simply “stopping”. |
| OCD is a personality trait | OCD is not the same as being perfectionistic, careful or particular. It is a mental health condition that can affect thoughts, emotions and behaviour. |
| OCD only affects adults | OCD can affect children, teenagers and adults. Symptoms may look different depending on age, but early support can make a significant difference. |
| OCD is rare | OCD is more common than many people realise, but it is often hidden because people may feel ashamed, embarrassed or afraid to talk about their symptoms. |
| OCD cannot be treated | OCD is treatable. Many people improve with evidence-based support such as CBT with ERP, medication, or a combination of both. |
| If someone seems calm, their OCD cannot be serious | OCD is not always obvious from the outside. A person may appear calm while spending hours battling intrusive thoughts, mental rituals or avoidance. |
About Unique Community Services: We provide CQC-regulated home-based complex care to people of all ages with multiple needs, including autism, learning disabilities, and physical disabilities. As care providers, our ultimate goal is to ensure that the people we serve and their families feel relieved, confident, and satisfied with the support they receive.
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FAQs
Is OCD Hereditary?
OCD may be partly hereditary, but it is not caused by one single gene and it is not inevitable. It can run in families, which suggests that genetics may play a role. However, having a family member with OCD does not mean someone will definitely develop it. OCD is usually understood as being influenced by a mix of factors, including genetics, brain processes, life experiences, stress and environment.
Can OCD Go Away?
OCD can improve significantly with the right treatment and support, but it may not simply “go away” on its own. Many people learn to manage OCD so that intrusive thoughts feel less powerful, compulsions reduce, and daily life becomes easier.
Is OCD a type of autism?
No, OCD is not a type of autism. OCD is a mental health condition involving intrusive thoughts and compulsive behaviours, while autism is a neurodevelopmental condition that affects communication, sensory processing, social interaction and patterns of behaviour. They can sometimes look similar because both may involve routines, repetition or distress around uncertainty, but the reasons behind these behaviours are different.le are born with autism.
