Skip to content
View commentaries on this research

This is a plain English summary of an original research article

Offering people guided self-help whilst on a waiting list for therapist-led therapy did not improve their obsessive-compulsive symptoms when assessed after three or 12 months. However, these low-intensity interventions may reduce the likelihood of people taking up therapist-led cognitive behavioural therapy (CBT).

This NIHR-funded trial included 473 adults with moderate to severe obsessive-compulsive disorder (OCD) who were already waiting to receive CBT. Issues with the uptake of the low-intensity interventions and therapist-led therapy may have affected results but probably reflect the challenges of engaging people with these symptoms into therapy.

There is a possibility that the book- or computer-based CBT therapies could be effective in people with milder OCD symptoms, but it is unlikely to be the best strategy for people with moderate to severe symptoms.

Why was this study needed?

Obsessive-compulsive disorder is a common mental health condition affecting around 1.2% of the UK population. People either have obsessional thoughts or compulsive acts. Commonly they have both. The obsessions are repeated unwanted and unpleasant thoughts, images or urges which cause anxiety. Compulsions are physical or mental acts that people feel compelled to repeat, such as hand washing or counting.

These thoughts and acts interfere with people’s everyday life, affecting them personally and professionally to a varying extent, with around half having severe symptoms.

Medication and behavioural therapy can help people manage the condition. However, people sometimes have to wait to access specialist therapy due to the limited number of therapists. Attending appointments can also be difficult depending on the nature of the obsessions or compulsions.

This NIHR-funded trial explored the impact of giving people self-help materials with some support while they waited for more intensive treatment.

What did this study do?

The Obsessive Compulsive Treatment Efficacy Trial (OCTET) randomly allocated 473 people with obsessive-compulsive disorder from 15 UK sites to remain on the waiting list for cognitive behavioural therapy (CBT), or receive one of two low-intensity forms of CBT with a focus on exposure and response prevention.

These were computerised CBT (cCBT) with phone support or a guided self-help CBT book, with weekly phone calls. The support for each intervention was provided by “psychological well-being practitioners” who had one year of training and limited CBT experience. For more information see the Definitions tab.

People remained on the waiting list for a shorter amount of time than researchers had expected - 42% of the waiting list controls, 21% of the cCBT and 23% of the guided self-help group received CBT within three months. This may have biased results in favour of the waiting list and also not be reflective of waiting list experiences across the UK.

What did it find?

  • Computerised cognitive behavioural therapy (cCBT) did not significantly improve obsessive-compulsive disorder (OCD) symptoms after three months compared to staying on the waiting list, assessed using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) from 0, no symptoms to 40 severe (Y-BOCS adjusted mean difference [aMD] ‑0.71, 95% confidence interval [CI] ‑2.12 to 0.70).
  • Guided self-help led to a statistically significant, but not clinically important, improvement in OCD symptoms at three months (aMD ‑1.91, 95% CI ‑3.27 to ‑0.55).
  • Having cCBT or guided self-help before therapist-led CBT did not lead to a clinically significant difference in people’s OCD at 12 months, compared to waiting list then therapist-led CBT. Average baseline Y-BOCS scores were 25 in each group and improved to 16 for cCBT, 15 for guided self-help and 18 for the waiting list (cCBT versus waiting list ‑1.37, 95% CI ‑3.59 to 0.84; guided self-help versus waiting list ‑2.37, 95% CI ‑4.37 to ‑0.38).
  • Accessing cCBT or guided self-help significantly reduced the likelihood that people would take up therapist-led CBT by 12 months (cCBT adjusted odds ratio [aOR] 0.34, 95% CI 0.15 to 0.79; guided self-help aOR 0.27, 95% CI 0.12 to 0.60). The proportion having started CBT was 86% from the waiting list control group, 62% from the group and 57% the guided self-help group. Overall, though, this did not seem to compromise patient outcomes at 12 months.

What does current guidance say on this issue?

NICE 2005 guidelines recommend “stepped care” – where the intensity of treatment is related to the severity of symptoms and response to each treatment.

Up to 10 hours of individual cognitive behavioural therapy (CBT) using self-help materials or by telephone, or group CBT is recommended for people with mild obsessive-compulsive disorder (OCD). For moderate OCD, they recommend using either medication (a selective serotonin reuptake inhibitor, SSRI) or 10 hours of more intensive CBT. A combination of a SSRI and intensive CBT are recommended for people with severe OCD. The CBT for each level focuses on exposure and response prevention.

Intensive treatment and inpatient services are recommended only for people with serious OCD that presents a risk to their life, causes extreme distress and functional impairment.

What are the implications?

Giving people with moderate to severe obsessive-compulsive disorder (OCD) a guided self-help form of cognitive behavioural therapy (CBT) while they waited for therapist-led CBT didn’t improve their clinical outcomes but did reduce the likelihood of them subsequently having therapist-led CBT.

This may have been due to low uptake – 59% started computerised CBT and completed an average of two out of six sessions, while 65% started guided CBT with four out of 10 sessions completed. It is not clear why these two groups also had reduced uptake of therapist-led CBT or why there were no differences in outcomes between all three groups by 12 months.

Further information on this and other research on OCD treatment can be found in the recently published NIHR Highlight.


Citation and Funding

Lovell K, Bower P, Gellatly J, et al. Clinical effectiveness, cost-effectiveness and acceptability of low-intensity interventions in the management of obsessive compulsive disorder: the Obsessive Compulsive Treatment Efficacy randomised controlled Trial (OCTET). Health Technol Assess. 2017;21(37).

This project was funded by the National Institute for Health Research Health Technology Assessment Programme (project number 09/81/01).



NHS Choices. Obsessive compulsive disorder (OCD). London: Department of Health; 2016.

NICE. Obsessive-compulsive disorder and body dysmorphic disorder: treatment. CG31. London: National Institute for Health and Care Excellence; 2005.

NIHR. Obsessive Compulsive Treatment Efficacy Trial (OCTET). London: National Institute for Health Research; 2011.

Lovell K, Bower P, Gellatly J, et al. Low-intensity cognitive-behaviour therapy interventions for obsessive-compulsive disorder compared to waiting list for therapist-led cognitive-behaviour therapy: 3-arm randomised controlled trial of clinical effectiveness. PLoS Med. 2017;14(6):e1002337.

OCD UK. How common is OCD? London: OCD UK.

OCD UK. Treatments for OCD. London: OCD UK.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre


  • Share via:
  • Print article


Computerised cognitive behavioural therapy used a nine-step programme called OCFighter. Participants were advised to use the programme at least six times over 12 weeks and received six 10-minute phone calls to review progress and offer problem-solving.For guided self-help participants had an introductory session of 60 minutes (face-to-face or via telephone) to the workbook Obsessive compulsive disorder: a self-help book, followed by 10 30-minute sessions over 12 weeks. These covered using the workbook, devising goals, reviewing progress and problem-solving.Both programmes used elements of exposure and response prevention, which helps people to change how they react to their obsessive thoughts. 
Back to top