A common treatment question is whether trauma-focused therapy should begin while someone is receiving care for a substance-use disorder or wait until later.

A randomized trial at two addiction-treatment centers in the Netherlands tested both approaches. The study included 209 adults with posttraumatic stress disorder and a substance-use disorder. Participants received one of three PTSD treatments: eye movement desensitization and reprocessing, prolonged exposure, or imagery rescripting.

Some participants began PTSD treatment while continuing substance-use care. Others received substance-use treatment first and waited three months before beginning PTSD treatment. Each trauma-focused condition offered 12 sessions.

At the three-month assessment, patients who started both forms of treatment during the same period had greater improvement in PTSD symptoms than those assigned to the delayed schedule. That comparison needs context: the delayed group had not yet begun PTSD treatment.

At six and nine months, clinician-rated PTSD severity did not differ significantly between the simultaneous and sequential groups. Most participants reported preferring the simultaneous schedule.

The trial also compared the three trauma-focused treatments. PTSD severity did not differ significantly among EMDR, prolonged exposure, and imagery rescripting at the later assessments. Imagery rescripting had a higher PTSD-treatment completion rate than EMDR or prolonged exposure. Substance-use outcomes did not differ among the groups.

A newer secondary analysis examined changes beyond PTSD and substance-use symptoms. Researchers considered psychological distress, emotion regulation, interpersonal problems, anger control, and trauma-related guilt and shame.

At three months, adding EMDR or imagery rescripting to substance-use care was associated with improvement in several of those areas, while prolonged exposure did not show the same pattern in those analyses. Direct comparisons among EMDR, prolonged exposure, and imagery rescripting nevertheless found no significant differences between treatment types. The results should not be read as evidence that EMDR or imagery rescripting was superior to prolonged exposure.

Simultaneous treatment also produced earlier psychosocial improvement than delayed treatment. Here again, much of the difference appeared before the delayed group had begun PTSD therapy. The finding supports examining earlier access; it does not establish that concurrent care produces better long-term outcomes for every patient.

The trial's setting and eligibility boundaries also matter. It was conducted in two Dutch addiction-treatment centers and excluded people facing several acute circumstances, including high acute suicide risk, recent suicide attempt, life-threatening self-injury, current abuse or death threats, homelessness, acute psychosis, and certain active legal proceedings. The findings cannot automatically be generalized to people in those situations or to every treatment setting.

The authors found no evidence that adding trauma-focused treatment worsened substance-use outcomes. That is reassuring, but it is not the same as a comprehensive analysis of every possible adverse effect.

Taken together, the studies challenge the idea that trauma-focused treatment must routinely wait simply because a substance-use disorder is present. They do not establish one schedule or therapy as the right choice for everyone. The authors recommend shared decision-making that considers the available treatments, treatment history, and patient preferences.

Questions Readers May Have

Did concurrent treatment produce better long-term PTSD outcomes?

Not in this trial. Concurrent treatment produced earlier improvement, but PTSD severity did not differ significantly between simultaneous and sequential treatment at six or nine months.

Did EMDR outperform prolonged exposure or imagery rescripting?

No significant PTSD-severity differences were found among the three treatments at the later assessments. The psychosocial secondary analysis also found no significant direct differences between treatment types.

Why did concurrent treatment look better at three months?

The delayed group had not yet begun PTSD treatment during that initial period. The early comparison therefore partly reflects receiving PTSD treatment sooner.

Did trauma-focused treatment worsen substance-use outcomes?

The study found no between-group worsening of substance-use outcomes. That is reassuring, but it should not be presented as a comprehensive assessment of every possible adverse effect.

Does this mean PTSD treatment should always begin immediately during substance-use care?

No. The trial supports questioning automatic delay, not applying one schedule to everyone. The setting, eligibility criteria, acute-risk exclusions, available treatments, treatment history, and patient preferences still matter.

Selected Sources

• Lortye et al. Timing and type of posttraumatic stress disorder treatment in patients with co-occurring substance use disorder and posttraumatic stress disorder - A randomized controlled trial. Journal of Substance Use and Addiction Treatment. Volume 183, article 209878, 2026.
• Lortye et al. Effects of timing and type of trauma-focused treatment on psychosocial functioning. Behaviour Research and Therapy. Volume 202, article 105053, 2026.
• Amsterdam UMC. Institutional record and manuscript access.