Frequently Asked Questions

Yes. In this retrospective real-world sample of 181 adults with comorbid obsessive-compulsive disorder and posttraumatic stress disorder, concurrent delivery of exposure and response prevention (ERP) for OCD and prolonged exposure (PE) for PTSD by therapist-delivered video sessions was associated with significant improvement in both disorders. Treatment was delivered within the same treatment episode by the same therapist, with session focus alternating between OCD and PTSD based on clinical presentation rather than treating one disorder to completion before starting the other.

PTSD symptoms improved significantly over treatment. Mean PCL-5 scores decreased from 43.5 (SD 14.2) at baseline to 35.0 (SD 15.4) at session 20, a change of -8.5 points (19.5%) with Hedges g = 0.56 (95% CI, 0.39-0.73), and to 33.8 (SD 17.2) at session 40, a change of -9.7 points (22.3%) with Hedges g = 0.64 (95% CI, 0.39-0.89). By each patient's final session, mean PCL-5 scores had fallen to 26.4 (SD 17.6), a -17.1-point change (39.3%; F1,180 = 194.13, P<.001) with Hedges g = 1.03 (95% CI, 0.85-1.21).

OCD symptoms also improved significantly. Mean DOCS scores decreased from 35.2 (SD 13.7) at baseline to 24.5 (SD 14.4) at session 20, a -10.7-point reduction (30.4%) with Hedges g = 0.77 (95% CI, 0.59-0.95), and to 25.4 (SD 15.2) at session 40, a -9.8-point reduction (27.8%) with Hedges g = 0.84 (95% CI, 0.58-1.1). By the final session, mean DOCS scores had decreased to 19.5 (SD 13.9), a -15.7-point change (44.7%; F1,180 = 244.55, P<.001) with Hedges g = 1.16 (95% CI, 0.97-1.35).

By the final session, 49.2% of patients (89/181) met the study's combined response definition for both disorders at the same time: at least a 35% reduction on the DOCS and at least a 10-point reduction on the PCL-5. Looking at each disorder separately at the final session, 67.4% (122/181) achieved at least a 10-point PCL-5 reduction, 75.7% (137/181) achieved at least a 25% DOCS reduction, and 64.1% (116/181) achieved at least a 35% DOCS reduction.

At session 40, combined response had been reached by 17.1% (13/76) of those with available PCL-5 data and 77 available DOCS assessments; at that point, 36.8% (28/76) had a PTSD response, 58.4% (45/77) had at least a 25% DOCS response, and 42.9% (33/77) had at least a 35% DOCS response.

Among patients who achieved and maintained response through their final session, OCD response appeared earlier than PTSD response. The median time to first maintained response was 11 sessions for OCD (IQR, 8-19) and 15 sessions for PTSD (IQR, 8-23), while dual response in both conditions first occurred at a median of 20 sessions (IQR, 13-27).

• For OCD responders, 81.9% first responded within 20 sessions.
• For PTSD responders, 68.0% first responded within 20 sessions.
• For dual responders, 55.0% first responded within 20 sessions, and 13.5% required more than 40 sessions.

This was delivered at a standard outpatient pace rather than an intensive schedule. Patients attended a median of 1.1 sessions per week (IQR, 0.9-1.3), which the authors described as approximately 4 to 6 sessions per month, and completed a median of 34 total sessions (IQR, 24-56) over 34.6 weeks (IQR, 21.7-48.4).

The median treatment episode included 24 OCD-focused sessions (IQR, 13-40) and 11 PTSD-focused sessions (IQR, 6-16). Session focus alternated based on which condition was being prioritized clinically, and these recommended frequencies were not additive.

Yes. Concurrent ERP and PE was associated with significant improvement across all measured secondary outcomes from baseline to final session, and all primary and secondary outcomes remained significant after Benjamini-Hochberg correction (all adjusted P<.001).

• Depression (DASS-21 Depression) decreased from 17.6 (SD 10.4) to 12.3 (SD 10.6), F1,180 = 42.97, P<.001.
• Anxiety (DASS-21 Anxiety) decreased from 16.6 (SD 8.8) to 10.8 (SD 8.4), F1,180 = 68.90, P<.001.
• Stress (DASS-21 Stress) decreased from 22.4 (SD 8.7) to 15.7 (SD 9.4), F1,180 = 77.09, P<.001.
• Functional disability (WHODAS 2.0) decreased from 26.8 (SD 7.8) to 22.1 (SD 8.6), F1,178 = 95.88, P<.001.
• Quality of life (Q-LES-Q-SF) increased from 50.5 (SD 14.2) to 59.9 (SD 16.9), F1,178 = 78.91, P<.001.

No significant moderation by baseline psychiatric medication status was found for either PTSD or OCD outcomes. The authors reported that concurrent ERP and PE was similarly effective regardless of baseline medication use, meaning patients taking medication at treatment entry and those not taking medication showed comparable symptom improvement in this analysis.

Treatment was delivered concurrently, meaning ERP for obsessive-compulsive disorder and prolonged exposure for posttraumatic stress disorder were provided within the same treatment episode by the same therapist, with session focus alternating based on clinical presentation. Sessions were labeled as primarily OCD-focused or PTSD-focused, but therapists could address both conditions in the same session when symptoms interacted.

This differs from sequential treatment, in which one disorder is treated to completion before the other, and from integrated treatment, in which techniques from multiple protocols are systematically combined within every session according to a structured protocol.

The findings are promising, but the study was observational and retrospective, so it cannot determine how concurrent ERP and PE compares with sequential treatment, single-protocol treatment, or no treatment. There was no randomized comparison group and no formal treatment fidelity review such as session video ratings, although therapists had standardized training and biweekly consultation.

Other important limitations were that only 42.5% of patients reached session 40, reasons for ending earlier varied, routine postdischarge follow-up was not available, outcomes relied on self-report measures (PCL-5 and DOCS), acceptability could not be assessed because the study did not track who declined treatment, and the effects of added support features such as therapist messaging, support groups, and online community access could not be separated from the psychotherapy itself.