22nd February 2024

Obsessive-Compulsive Disorder

Background

Obsessive-compulsive disorder (OCD) is a mental health disorder characterised by obsessions and impulses, followed by compulsion or repetitive behaviours. OCD is a serious mental illness that often has a debilitating effect on the individual’s quality of life and day to day function. It affects 2% of the population and occurs in men and women equally. Neuroimaging has shown a reduction in inhibition in the frontal lobe in OCD sufferers, making it more difficult for them to resist distressing and intrusive thoughts.

Presentation

Obsessions

These are unwanted and intrusive thoughts, ideas, or impulses which sufferers would find disturbing, unsettling and difficult to get rid of despite trying to resist. The patient will often recognise these thoughts as being irrational and as being their own, unlike in other mental health disorders where there may be thought insertion or delusional beliefs. As OCD becomes chronic, the ability to resist these ideas or impulses can decrease or disappear.

There are common themes with these obsessions:  aggression (thoughts of harming others), contamination, infection, and morality (religion /sex)

Whilst having unpleasant thoughts can occasionally be normal, in persons with OCD these thoughts cannot be ignored or resisted. These obsessions make the patient feel unsettled, distressed and worried about what they’ll do if they keep having these thoughts or the danger their thoughts pose to them and their loved ones. 

Compulsions

A compulsion is the action patients feel they need to undertake to decrease or neutralise the obsession or intrusive thought. It is a safety strategy to prevent the frightening consequences caused by their obsession. These compulsions, also known as OCD rituals, are usually repetitive and usually follow a set of rules. The person usually recognises these rituals to be pointless and initially, they try to resist. These compulsions or rituals can be physical or mental tasks the patient needs to do to get rid of the obsessional thought or thoughts.

These compulsions or rituals can be put into 4 main categories:

1. Repeating actions e.g., patients checking locks a certain number of times to protect themselves from an intruder or repeating a word in their head constantly
2. Rituals to decontaminate e.g. excessive cleaning, showering several times a day, repeatedly washing hands.
3. Ordering and arranging e.g. mentally reviewing lists
4. Constant checking and reassurance seeking e.g. patients analysing or reanalysing things they’ve done or said several times in their head until it is perfect

These rituals can often take hours to perform and have a negative impact on the patients’ quality of life as they feel compelled to do these rituals to get rid of the distress caused by the obsessional thoughts. They often recognise these actions to be irrational or completely unrelated to the intrusive thought but feel compelled to carry them out anyway. 

Risk factors 

• Family history 
• Pregnancy
• Male sex
• Paediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS)

Diagnosis

The presentation of OCD overlaps with other psychiatric disorders, such as anxiety and depressive disorders, making diagnosis difficult. On average, it takes 9 years before OCD is correctly diagnosed, with around 17 years between the first onset of symptoms and appropriate treatment.  Patients are often embarrassed and avoid reporting their symptoms. In some cases, they present to health care professionals due to a medical condition which has resulted from their OCD e.g. dermatitis caused by excessive hand washing. 

ICD-10 for OCD diagnosis requires there to be recurrent obsessional thoughts or compulsive actions.

Differentials 

OCD is very similar to anankastic personality disorder. This is where individuals have rigid ways of doing things and have high standards of hygiene and cleanliness, which is often confused with OCD. However, the key difference is the lack of compulsive and repetitive behaviour.

Investigation

• Structured clinical interview for the DSM (SCID-5). This SCID-5 is derived from the DSM-5 and is a tool used to assess whether a patient meets the DSM-5 criteria for OCD. This tool is commonly used in research settings. 
• Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). This is not a diagnostic tool but is used to determine the severity of OCD symptoms. It should be used at the start and during treatment to assess progress. 
• Clinical global impression (CGI)

Management

Treatment, as with other anxiety disorders, consists of a stepped approach. 

Mild functional impairment

• Education and self-help
• Low intensive CBT remains the first-line therapy. In OCD, the CBT intervention used is called exposure and response prevention (ERP). When a patient gets an obsessional thought, they are encouraged to sit with the feeling of anxiety and distress this causes instead of carrying out a compulsion. They are encouraged to discuss the feelings the obsession causes with the therapist. Similar exposure therapy is used in PTSD. This form of CBT is believed to be extremely effective. 

If a patient is unable to undertake low intensity CBT, or is not responsive to it, they should be treated for moderate functional impairment. 

Moderate functional impairment

• A choice of intensive CBT with ERP or drug therapy can be offered. 
• SSRI is the first line for drug therapy. Escitalopram, fluoxetine, sertraline, and paroxetine are all licensed for OCD. Citalopram can also be used as a first line; however, it is currently unlicensed for OCD.
• Clomipramine (TCA) can be given if SSRIs are contraindicated, if the patient prefers the TCA or if they’ve had a better response with it previously. 

Patients who do not receive enough benefit from these treatments should be treated for severe functional impairment. 

Severe functional impairment

• Dual therapy: intensive CBT combined with drug treatment
• Referral to specialist psychiatric services- consider if the OCD is chronic, debilitating and restricting daily life. Also, consider referral in patients who are not improving despite having >2 courses of CBT, including ERP in combination with antidepressants. 

References

• Simpson HB. https://www.uptodate.com/contents/obsessive-compulsive-disorder-in-adults-epidemiology-pathogenesis-clinical-manifestations-course-and-diagnosis?search=ocd&source=search_result&selectedTitle=2~145&usage_type=default&display_rank=2 [Internet]. UpToDate. Wolters Kluwer; 2022 [cited 2023May1]. Available from: https://www.uptodate.com/contents/obsessive-compulsive-disorder-in-adults-epidemiology-pathogenesis-clinical-manifestations-course-and-diagnosis?search=ocd&source=search_result&selectedTitle=2~145&usage_type=default&display_rank=2 
• Streeruwitz A, Hagger M, Webb S, Walker D, Jakeman N. Anxiety, obsession, and reactions to stress. In: Psychiatry PRN. Oxford, New York: Oxford University Press; 2009. p. 15156–157. 
• 1. BMJ best practice. Obsessive-compulsive disorder [Internet]. 2022 [cited 2023 Oct 6]. Available from: https://bestpractice.bmj.com/topics/en-gb/362