Cognitive explanations of OCD suggest that spontaneous/intrusive thoughts only turn into obsessions if people hold dysfunctional beliefs and interpret their thoughts in maladaptive ways. Cognitive bias modification (CBM) is a branch of cognitive therapy that targets negative cognitive biases. For example, people prone to OCD may interpret ambiguous information in a negative way. CBM aims to reduce this bias with the indirect effect of reducing negative emotions during situations that could trigger compulsive behaviours.

The following study investigated the effectiveness of cognitive bias modification in the treatment of OCD.

A volunteer sample of 89 adults with intrusive thoughts and/or compulsive behaviours completed a self-report questionnaire, measuring the severity of their OCD symptoms. They were then randomly allocated to either the control condition or the positive condition.

The CBM sessions involved imagining oneself in 164 situations that tapped into the core beliefs in OCD, e.g. overestimation of threat. For example “You are riding the bus home from work. The passenger beside you sneezes so you offer them a tissue. You think to yourself that offering a tissue was a behaviour that was k_nd/ r_sky’. The participants had to fill in an ‘i’ to make the word ‘kind’ (positive condition) or the word ‘risky’ (control condition). In the positive condition, all scenarios had positive endings, cueing the participants to anticipate positive outcomes. In the control condition, only half the scenarios had positive endings, meaning participants could not anticipate the ending.

The researchers measured interpretation bias to see whether the participants changed from a negative to a positive bias following the CBM intervention. The researchers looked at biases relating specifically to core beliefs associated with OCD, as well as a more general positive/negative bias. Next, the participants took part in the CBM training session, in either the positive or control condition. After the training, they completed the interpretation bias task again, plus three behavioural tasks.

Cognitive therapy is usually conducted over several weeks/months, not a single session as with this study. This means it is impossible to know how effective CBM would be if delivered over a longer period and how durable the effects might have been. For example, the positive bias may have worn off unless ‘topped up’ again with further CBM sessions. For this study, only short-term effects were measured.

The behavioural measures may have been ineffective due to poor task design; the tasks may not have picked up more subtle changes in behaviour, or it may simply have required a greater amount of CBM to observe behavioural changes. Furthermore, the tasks were not individualized to the different types of OCD symptoms experienced by the participants.

The research was not conducted on a clinical sample, i.e. the participants had not received a diagnosis of OCD so generalizations should be made with caution. However, the fact that CBM was effective for people with both mild and severe symptoms suggests it should be effective for people with a diagnosis.

In terms of practicality, CBM can be delivered remotely via the Internet or a mobile phone app and therefore provides a cost-effective solution for people who do not have time or cannot afford to see a therapist. As 42% of people with OCD are not currently receiving therapy, research such as this is critical to the well-being of a large sector of society.