March et al. (2004) POTS Study: CBT, Sertraline and Their Combination in OCD Revision Notes for Edexcel A-Level Psychology

March et al. (2004) POTS Study: CBT, Sertraline and Their Combination in OCD

Study details

Theorist: March et al.
Title: Paediatric OCD Treatment Study (POTS) - Cognitive Behavior Therapy, Sertraline and Their Combination for Children and Adolescents with OCD
Year: 2004

Participants

112 children and adolescents aged 7-17 years (mean age 11.7 years)
Volunteer sample recruited from those diagnosed with OCD using DSM-IV
97 participants completed the study (87% completion rate)
Participants scored 10 or above on the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS), indicating moderate to severe symptoms
Children with comorbid disorders (Tourette's syndrome, major depression) were excluded to prevent interaction effects
Children with ADHD were included if they were on stable stimulant medication and not taking anti-obsessional medication at the study's start

infoNote

The Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) is a standardised assessment tool specifically designed to measure OCD symptom severity in young people. A score of 10 or above indicates moderate to severe symptoms, while scores below 10 indicate remission or mild symptoms.

Aim

The study investigated whether CBT alone is more or less effective than drug treatment (sertraline), or whether combining both treatments is more effective for treating young people with OCD. The research was funded by the National Institution for Mental Health in the USA to identify the most effective early intervention for paediatric OCD, given that 1 in 200 young people develop OCD and 33-50% of adult sufferers developed the condition during childhood.

Procedure

Random allocation

Participants were randomly allocated to one of four conditions using a computerised system:

CBT-only
Drug-only (sertraline)
Combination (CBT and sertraline)
Placebo-pill only

Measurement

All children were interviewed and baseline measurements taken using the CY-BOCS by independent evaluators
Participants were reassessed at weeks 4, 8, and 12 by independent evaluators trained to a reliable standard
Each child had an assigned specialist psychiatrist to monitor progress and provide support throughout the study
The assessment process was strictly supervised and reviewed to establish reliability

chatImportant

Assessors were kept blind to the participants' treatment conditions throughout the study to prevent bias in evaluation. This double-blind design strengthened the validity of the findings by ensuring that expectations did not influence the measurement of outcomes.

Treatment protocols

infoNote

Drug-only and placebo conditions:

Children attended weekly appointments for the first six weeks, then fortnightly (nine sessions total)
Medication dosage was established and adjusted as necessary during clinical sessions
Parents monitored medication compliance at home and maintained a medication diary
Any adverse reactions resulted in medication being changed or stopped

infoNote

CBT-only condition:

14 clinical sessions over the 12-week period
Therapy followed a standardised CBT manual including:
- Psychological education
- Cognitive training
- Mapping OCD target symptoms
- Exposure and response ritual prevention
Each session involved goal-setting, reviewing the previous week, therapist-assisted practice, homework, and monitoring
The manual was applied flexibly according to each child's developmental stage

infoNote

Combination condition:

Both drug and CBT sessions provided simultaneously (time-linked)
A CBT and placebo comparison was not included

Findings

All four conditions showed improvement at 12 weeks as measured on the CY-BOCS. However, the placebo improvement was not substantial.

Symptom reduction data

Condition	Baseline measure	Final measure	Difference
CBT alone	26	14	-12
Drug alone (sertraline)	23.5	16.5	-7
Combination	23.8	11.2	-12.6
Placebo	25.2	21.5	-4.7

chatImportant

The data shows that CBT alone produced a 12-point reduction in symptoms, nearly double the effect of sertraline alone (7-point reduction). The combination therapy showed only a marginally better result (12.6-point reduction) compared to CBT alone.

Remission rates

CBT-alone condition: 39.3% entered remission (score dropped below 10 on CY-BOCS)
Drug-alone condition: 21.4% entered remission
Combination condition: Marginally higher than CBT alone

The CBT-alone condition demonstrated the highest single-treatment effectiveness, with combination treatment showing only marginal additional benefit.

Conclusion

The study demonstrated a clear effect of CBT, producing higher improvement rates than drug treatment alone. This suggests CBT should be the first-line treatment for paediatric OCD. Whilst minimal additional gain can be achieved by including sertraline when effective CBT is provided, the drug may compensate for less effective therapy.

chatImportant

SSRIs require careful monitoring as they have been linked to suicidal ideation in young people. Despite this concern, the study showed that treatment was well tolerated across all conditions with appropriate monitoring protocols in place.

Evaluation: Strengths

Well-controlled study design:

The study was conducted across three centres and run by two universities in tandem, providing robust data collection and analysis. Randomised allocation to conditions eliminated selection bias, while the use of a standardised CBT manual across all centres maintained consistency in treatment delivery.

infoNote

The multi-centre approach enhanced the generalisability of findings by demonstrating that results were consistent across different geographical locations and clinical settings.

High reliability in measurement:

Assessors were blind to the participants' treatment conditions, preventing bias in evaluation of improvements
Participants in the placebo condition were unaware the drug was inactive, as was the therapist
Assessors received training and monitoring to ensure reliability in measuring change
The CY-BOCS is a well-recognised, valid, and reliable assessment tool

Strong ethical standards:

The study maintained exemplary ethical practices throughout. All participants and at least one parent provided full written informed consent. Each participant had an assigned psychiatrist for monitoring and support throughout, ensuring participant wellbeing was prioritised.

infoNote

Those on medication were regularly checked, with dosages changed as necessary to protect participants from harm. Participants in the placebo condition were offered therapy upon study completion, ensuring no participant was denied effective treatment long-term.

Representative sample:

Large sample size (112 participants, 97 completers) with low drop-out rate (87% completion)
Sample was representative of the target population (children and adolescents with OCD)
Analysis in each condition showed no differences in outcome attributable to individual differences between target groups

Evaluation: Weaknesses

Therapist effects:

One centre showed better results on the CBT-only condition, which might be due to a therapist effect. This suggests that one centre may have been more proficient at delivering CBT. However, all centres used the standardised CBT manual to maintain treatment consistency.

chatImportant

The presence of therapist effects highlights a common challenge in psychotherapy research: even with standardised manuals, the skill and experience of individual therapists can influence treatment outcomes.

Limited generalisability:

Exclusion of children with comorbid conditions (Tourette's syndrome, major depression) means findings may not generalise to all young people with OCD
The study only examined sertraline as the drug treatment option

Combination condition design:

No CBT and placebo comparison was included, which would have provided additional insight into the specific effects of CBT versus expectation effects.

bookmarkSummary

Key Points to Remember:

The POTS study compared four treatments for paediatric OCD: CBT alone, sertraline alone, combination therapy, and placebo
CBT alone showed the greatest effectiveness, with 39.3% of participants entering remission compared to 21.4% in the drug-only condition
The combination of CBT and sertraline produced only marginally better results than CBT alone
The study was well-controlled with randomised allocation, blind assessors, and standardised treatment protocols
Key weaknesses include potential therapist effects and limited generalisability due to exclusion of participants with comorbid conditions

March et al. (2004) POTS Study: CBT, Sertraline and Their Combination in OCD (Edexcel A-Level Psychology): Revision Notes