A randomised controlled feasibility trial comparing the clinical and cost effectiveness of cognitive behavioural therapy (CBT) and selective serotonin reuptake inhibitors (SSRI) and their combination in the management of obsessive compulsive disorder

Obsessive Compulsive Disorder (OCD) is a major mental illness, ranked
as a leading cause of disability and a health-research priority. OCD
seriously affects quality of life. Most patients develop secondary disorders,
such as depression and anxiety.
Current treatment guidelines for OCD recommend either psychological
(cognitive-behavioural) therapy (CBT) or medication first-line and only
severe cases are treated with a combination of the two. While it is
assumed that the combination of CBT and medication would be more
effective than either given alone, the evidence to support this is weak.
The National Institute for Health and Clinical Excellence (NICE CG31;
www.NICE.org.uk) recommends the best methods to manage and treat
diseases. Their guidance on OCD proposes that a large clinical trial is
needed to investigate whether the combination of CBT and medication is
more effective than either CBT alone or medication alone.
Large randomised controlled trials are the best method for investigating the
effectiveness of different therapies. However, given the large numbers of
people and the resources involved, they are costly, time-consuming and
require careful planning. As the existing evidence is unclear and we are
unable to determine from it to what extent each of these treatments is likely
to be successful, it is recommended that a small version of the trial
(‘feasibility study’) is conducted in advance of the substantive trial. This
allows the research-team to calculate more precisely the required number
of patients and identify any operational problems early on, so they can be addressed in the full trial.
We have therefore conducted a small-scale trial to investigate whether the
design of the study is appropriate. The findings may be used to develop a
larger, future study to investigate whether CBT and medication in
combination is more effective than either therapy alone in the treatment of
adults with OCD.