# Temporal sequencing of symptom change in youth receiving treatment for posttraumatic stress disorder and substance use: secondary findings from a randomised controlled trial

## TL;DR

This study examines how PTSD and substance use symptoms change over time in youth undergoing treatment, finding that an integrated therapy reduces PTSD symptoms but not substance use.

## Contribution

This is the first randomized trial to investigate temporal symptom change in youth with comorbid PTSD and SUD.

## Key findings

- Integrated treatment (COPE-A) significantly reduced PTSD symptoms compared to supportive counseling.
- No temporal or concurrent relationships were found between PTSD and substance use symptom changes.
- COPE-A was shown to be safe and effective for treating PTSD in youth with comorbid SUD.

## Abstract

Posttraumatic stress disorder (PTSD) and substance use disorders (SUD) frequently co-occur in youth. Integrated, trauma-focused treatments are recommended, but evidence in youth is limited and the dynamics of symptom change are poorly understood.

We investigated within-treatment changes in PTSD and substance use, and their temporal sequencing, in a randomised controlled trial (RCT) comparing integrated treatment with supportive counselling among youth aged 13–25 years.

Participants (n = 55) were randomised to an integrated, exposure-based treatment, Concurrent Treatment of PTSD and SUD Using Prolonged Exposure – Adolescent version (COPE-A); or supportive counselling, Person-Centred Therapy (PCT). PTSD and substance use symptoms were assessed at each session. Generalised estimating equations were used to analyse symptom change over time, and Spearman’s correlations were used to examine associations between early (sessions 1-5) and later (sessions 5-11) change.

COPE-A showed significantly greater reductions in total PTSD symptom severity during treatment (β = −17.00, 95% CI −29.50 to −4.46); with no between-group differences in substance use quantity or frequency. PTSD symptom clusters improved concurrently, but no temporal relationships were observed. Temporal relationships for substance use change were limited, and changes in PTSD symptoms were not associated with concurrent or subsequent changes in substance use.

Integrated, trauma-focused treatment reduced PTSD symptoms, reinforcing the safety and tolerability of exposure-based therapy in this youth sample with comorbid PTSD-SUD. PTSD improvement was not associated with either concurrent or subsequent reductions in substance use. Understanding temporal patterns of change may help refine models of PTSD-SUD comorbidity and optimise intervention delivery.

This is the first randomised trial to examine how posttraumatic stress and substance use symptoms change over time in youth with co-occurring posttraumatic stress disorder (PTSD) and substance use disorders (SUD).An integrated, exposure-based treatment (Concurrent Treatment of PTSD and SUD Using Prolonged Exposure – Adolescent Version; COPE-A) produced significantly greater reductions in posttraumatic stress symptoms than supportive counselling.Findings suggest that COPE-A is a safe and effective approach for youth with PTSD-SUD, however neither concurrent nor temporal relationships were observed between changes in PTSD and SUD symptoms, offering new insight into treatment mechanisms and ways to refine integrated care.

This is the first randomised trial to examine how posttraumatic stress and substance use symptoms change over time in youth with co-occurring posttraumatic stress disorder (PTSD) and substance use disorders (SUD).

An integrated, exposure-based treatment (Concurrent Treatment of PTSD and SUD Using Prolonged Exposure – Adolescent Version; COPE-A) produced significantly greater reductions in posttraumatic stress symptoms than supportive counselling.

Findings suggest that COPE-A is a safe and effective approach for youth with PTSD-SUD, however neither concurrent nor temporal relationships were observed between changes in PTSD and SUD symptoms, offering new insight into treatment mechanisms and ways to refine integrated care.