Our data lacked specificity regarding the duration and severity of chronic headache, TBI, and/or mental health conditions. We acknowledge that confounding variables such as life stress, psychological vulnerabilities (eg, hopelessness, impulsivity), sleep disturbance, concomitant medications, employment and marital status, and other social determinants of health may influence the associations between pain and suicidal behavior. Given that the comparison group in this analysis has other chronic pain conditions and not healthy control, it is less likely that the association we identified is spurious. The definition of chronicity using claim data may not always reflect the true characteristics of pain duration. For example, defining chronic headaches in this manner does not differentiate between a person who may have 2 headaches per month from someone who has more than 15 headaches per month. However, most likely those with persistent headache would have continued to follow up with their treating physicians. While this study captured medically confirmed SA, TBI, and chronic pain conditions using a broad range of ICD-9 codes, it is difficult to compile a completely comprehensive list of all possible ICD-9 codes to capture all patients with SA and different chronic pain conditions. It should be noted that EHR was only examined from 2000 to 2010, some veterans may have received a chronic pain diagnosis in years prior to this review, which could contribute to an underestimate of annual SA incidence at the beginning of the decade, the impact of this is likely low as we did not observe a significantly lower incidence in the first few years of the decade. In addition, patients who were lost to follow-up or chose to receive care outside the VHA system after their initial pain diagnoses were not included in our study. Finally, the use of physician verification for different types of pain, mental health, and SA may have resulted in underrepresentation. Historically, accurate reporting of suicide and suicide-related behaviors has been artificially low in most settings due to a number of factors including misclassification, fear and stigma, or a combination of factors.


Caution should also be taken when generalizing studies on veterans to the civilian population. The veteran population is primarily comprised of males. Patients with the VHA tend to be of higher acuity than the civilian population due to their unique military or combat experiences contributing to their medical conditions. Despite these limitations, the present study highlights the importance of chronic headache disorders and TBI in increasing SA risk.