How Does PTSD Affect Chronic Pain Treatment Outcomes?

What you need to know

• About 16% of chronic pain patients in this study had probable PTSD, but different patients were identified depending on which diagnostic criteria were used.
• PTSD symptoms measured by DSM-5 criteria correlated more strongly with psychological distress than PTSD measured by ICD-11 criteria.
• Only PTSD measured by ICD-11 criteria was associated with worse pain and disability outcomes after pain rehabilitation treatment.

PTSD in chronic pain patients

Posttraumatic stress disorder (PTSD) is fairly common among people with chronic pain conditions. However, there are different ways to diagnose PTSD, and it’s not clear how these different diagnostic approaches relate to outcomes when chronic pain patients receive treatment.

This study looked at two main ways of diagnosing PTSD:

1. The DSM-5 criteria, which take a broader view and include symptoms like negative changes in thoughts and mood

2. The ICD-11 criteria, which use a narrower definition focused on core PTSD symptoms

The researchers wanted to see how these two approaches compared when assessing PTSD in chronic pain patients, and whether one was better at predicting how patients would respond to pain rehabilitation treatment.

How the study worked

The study included 152 patients with chronic non-cancer pain who were starting treatment at a pain rehabilitation center in Denmark. Before beginning treatment, patients completed questionnaires to assess:

• PTSD symptoms (using both DSM-5 and ICD-11 criteria)
• Pain intensity
• Pain-related disability
• Other psychological factors like depression, anxiety, and pain catastrophizing

Patients then went through individualized pain rehabilitation programs, which could include medical treatment, psychological therapy, physical therapy, and group education sessions. After completing treatment, they filled out questionnaires again to reassess their pain and disability levels.

Key findings

PTSD prevalence and diagnosis

About 16% of patients met criteria for probable PTSD before starting treatment. Interestingly, the two diagnostic approaches (DSM-5 and ICD-11) identified similar overall rates of PTSD, but often in different patients:

• 16.4% had probable PTSD according to DSM-5 criteria
• 15.8% had probable PTSD according to ICD-11 criteria
• Only 17 patients (about 11%) were identified as having PTSD by both approaches

This shows that the choice of diagnostic criteria can significantly impact which patients are identified as having PTSD.

PTSD and psychological distress

PTSD symptoms measured by the DSM-5 criteria showed stronger correlations with other psychological issues like depression, anxiety, and pain catastrophizing compared to PTSD measured by ICD-11 criteria.

This likely reflects the broader nature of the DSM-5 criteria, which include symptoms that overlap more with general psychological distress. The ICD-11 criteria focus on core PTSD symptoms that are more distinct from other mental health conditions.

Impact on treatment outcomes

A key finding was that only PTSD measured by the ICD-11 criteria predicted worse outcomes after pain rehabilitation treatment. Specifically:

• Patients with probable PTSD according to ICD-11 criteria showed less improvement in pain-related disability after treatment compared to those without PTSD.

• PTSD measured by ICD-11 criteria was associated with both higher pain intensity and more disability after treatment, even after accounting for other psychological factors.

• PTSD measured by DSM-5 criteria did not significantly predict treatment outcomes once other psychological factors were taken into account.

What this means for patients and clinicians

These findings have important implications for assessing and treating PTSD in chronic pain patients:

1. Screening for PTSD is important, as a significant minority of chronic pain patients may have PTSD that could impact their treatment.

2. The choice of diagnostic criteria matters. Using different criteria may identify different patients as having PTSD.

3. The ICD-11 criteria for PTSD, while narrower, may be more useful for identifying chronic pain patients whose PTSD symptoms could interfere with pain rehabilitation outcomes.

4. Patients who screen positive for PTSD using ICD-11 criteria may need additional support or modified treatment approaches to achieve optimal pain rehabilitation outcomes.

5. The broader DSM-5 criteria may pick up on more general psychological distress that overlaps with other conditions. This distress is still important but may already be targeted by standard pain rehabilitation approaches.

Limitations and future research

This study had a relatively small sample size, so the findings need to be replicated in larger groups of patients. It also relied on self-report questionnaires rather than clinical interviews to assess PTSD. Future research could:

• Use larger patient samples to confirm these findings
• Employ clinical diagnostic interviews in addition to questionnaires
• Investigate whether different types of pain rehabilitation treatments are more or less effective for patients with PTSD
• Explore whether the relationship between pain and PTSD differs depending on whether they stem from the same traumatic event or separate events

Conclusions

• Different PTSD diagnostic criteria identify different patients, even if overall rates are similar.
• PTSD measured by narrower ICD-11 criteria may be more predictive of pain rehabilitation outcomes than broader DSM-5 criteria.
• Clinicians should consider using ICD-11-based screening tools to identify chronic pain patients whose PTSD symptoms may require additional attention during pain rehabilitation.