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Study breakdown

Patients with childhood trauma and PTSD started cannabis younger, used more, and had worse psychiatric outcomes than those without trauma

Cross SectionalModerate evidence
The takeaway

A study of 459 substance use disorder patients found a graded association between trauma history and outcomes: those with childhood trauma plus PTSD had the worst outcomes (earliest cannabis initiation, most cannabis use, most overdoses), followed by trauma-only, then no-trauma patients.

Addiction treatment providers; trauma-informed care advocates; clinicians treating co-occurring PTSD and substance use disorders.

Childhood trauma alone (without PTSD) was associated with worse substance use outcomes than no trauma

What the researchers found

Researchers divided 459 patients with substance use disorders into three groups: childhood trauma plus PTSD (CT-PTSD, n=95), childhood trauma without PTSD (CT-only, n=134), and no trauma (n=209).

A graded pattern emerged across nearly all outcomes, with CT-PTSD worst, CT-only intermediate, and no-trauma best.

Both trauma groups reported significantly higher anxiety, depression, suicidal thoughts, and suicide attempts than the no-trauma group.

The CT-PTSD group had significantly younger age at first cannabis and alcohol use, more cannabis use in the past month, and more lifetime drug overdoses compared to the no-trauma group.

The authors concluded that both childhood trauma and PTSD independently contribute to substance use severity, and treatment programs should assess and address both domains rather than focusing on one alone.

Why it matters

Many addiction treatment programs screen for PTSD but not for childhood trauma in the absence of PTSD. This study shows that childhood trauma alone (without meeting PTSD criteria) is associated with worse outcomes, suggesting that trauma-informed treatment should be broader than just PTSD treatment.

The numbers in context

459 patients: 95 CT-PTSD, 134 CT-only, 209 no trauma. CT-PTSD group had younger age at first cannabis and alcohol use, more past-month cannabis use, and more lifetime overdoses than no-trauma group. Graded association across all three groups.

How the study worked

Cross-sectional study of 459 SUD patients. PTSD diagnosed via IDCL and PDS. Childhood trauma assessed with CTQ. Substance use and psychiatric symptoms assessed with EuropASI. Three-group comparison (CT-PTSD, CT-only, no trauma).

What this study cannot tell us

Cross-sectional design cannot establish causal direction. Self-reported childhood trauma may be affected by current mental state. The CT-only group may include people with sub-threshold PTSD. Cannabis-specific effects are embedded within broader substance use patterns.

How to read the evidence

Moderate. Adequate sample with validated instruments and clear dose-response pattern, but cross-sectional design limits causal conclusions.

When this study was published

Published in 2018. Trauma-informed approaches to substance use treatment have continued to gain evidence and adoption.

The bigger picture

The graded dose-response pattern (more trauma burden = worse outcomes) reinforces the concept that trauma is not binary but exists on a spectrum that proportionally affects substance use trajectories.

Questions still open

  • Would trauma-specific therapy reduce cannabis use in these patients? Does childhood trauma cause earlier substance initiation, or do shared genetic/environmental factors drive both? Is the CT-only group an under-treated population?

Common questions

Why does childhood trauma affect substance use?
Childhood trauma can alter stress response systems, emotional regulation, and brain development in ways that increase vulnerability to substance use. People with trauma histories may use substances to manage difficult emotions, sleep problems, or intrusive memories.
Should trauma be treated before or alongside addiction?
This study supports integrated treatment that addresses both. The graded association suggests that treating only the substance use while ignoring trauma may miss an important driver of continued use and psychiatric symptoms.

Read the original research

Differential relationships of PTSD and childhood trauma with the course of substance use disorders.

Journal of substance abuse treatment, 93, 57-63

Citation

Mergler, Michaela; Driessen, Martin; Havemann-Reinecke, Ursula; Wedekind, Dirk; Lüdecke, Christel; Ohlmeier, Martin; Chodzinski, Claudia; Teunißen, Sibylle; Weirich, Steffen; Kemper, Ulrich; Renner, Walter; Schäfer, Ingo. (2018). Differential relationships of PTSD and childhood trauma with the course of substance use disorders.. Journal of substance abuse treatment, 93, 57-63. https://doi.org/10.1016/j.jsat.2018.07.010

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