Of the Sri Lanka Navy personnel deployed in combat areas, 10.4% reported ten or more physical symptoms. The prevalence was lower in the Special Forces than in the regular forces. There was significant association between multiple physical symptoms and PTSD and psychological morbidity. Multiple physical symptoms were associated with functional impairment.
Although unadjusted odds ratios showed significantly higher odds for those with higher educational level and non-combat personnel, these disappeared when we adjusted for service type. We found that regular forces were more likely than Special Forces to have higher educational level and be engaged in non-combat duty. Therefore, the association seen in the unadjusted analysis was due to a confounding factor.
In this study, the definition of a case of multiple physical symptoms was based on the top decile of the sample. In the study of UK military personnel, which used the same symptom list, the cases were defined as having 18 or more symptoms . When we used a cutoff of 18 symptoms, prevalence was 1.2% in the Special Forces and 2.9% in the regular forces which is much lower than in the UK sample. A study of 21,244 Gulf War veterans reported that 8.6% experienced ten or more symptoms which is similar to the prevalence in our sample . Prevalence of psychological morbidity such as PTSD, common mental disorders, fatigue, hazardous drinking, and smoking was also low in our sample [18, 27, 28]. Because PTSD and common mental disorders are probably involved in the etiology of multiple physical symptoms, lower rates of these conditions among SLN personnel could have influenced the rates of multiple physical symptoms.
It is interesting that the Special Forces reported lower rates of multiple physical symptoms compared to regular forces. They also had lower rates of fatigue and common mental disorders . Because Special Forces are exposed to more potentially traumatic events than regular forces, it may be assumed that they have higher rates of mental health problems. The ‘healthy warrior’ effect has been previously suggested as an explanation for the low rates of mental health problems among deployed military personnel . It suggests that psychologically unfit personnel drop out during training, and therefore, those deployed are healthier. This can explain the lower rates of multiple physical symptoms in the Special Forces. With the associated functional impairment, it is unlikely that personnel with high rates of physical symptoms can function satisfactorily in the Special Forces. In the regular forces too, those performing combat roles had less physical symptoms. Special Forces personnel such as Royal Marine Commandos and paratroopers were noted to have lower rates of multiple physical symptoms, fatigue, and general mental health problems . Apart from the ‘healthy warrior’ effect, rigorous selection and training of Special Forces personnel may also account for their increased resilience.
Comparison of prevalence of multiple physical symptoms is difficult because of the difference in the diagnostic criteria. Therefore, it may be more meaningful to compare the mean number of physical symptoms across studies. Gulf War veterans diagnosed with PTSD reported an average of 6.7 (SD 3.9) physical symptoms, those with a non-PTSD psychological condition 5.3 (SD 3.5), those with medical illness 4.3 (SD 3.4), and a group diagnosed as ‘healthy’ 1.2 (SD 2.2) . These are similar to our findings where the mean number of symptoms reported in personnel with PTSD was 12.19 (SD 10.58), common mental disorders 7.87 (SD 7.57), and those without these conditions 2.84 (SD 3.63). Physical symptoms are also known to be associated with post-traumatic stress symptomatology . Our study supports this observation because there was significant correlation between the number of physical symptoms and PTSD scale score (r = 0.671). The correlation between physical symptoms and PTSD symptoms is an important finding because many personnel did not meet the criteria for PTSD although they reported symptoms of PTSD.
Exposure to traumatic stress itself has been associated with unexplained physical symptoms and, to a lesser degree, poor physical health although . In our study ‘thought I might be killed,’ ‘coming under small arms fire,’ and ‘coming under mortar, missile and artillery fire’ were significantly associated with multiple physical symptoms, even after adjustment for socio-demographic variables. These events can be classified as ‘risk to self’ events [24, 25]. ‘Risk to life events’ are more strongly associated with PTSD than risk to other events such as witnessing dead or injured .
Multiple physical symptoms are associated with functional impairment, and this association remained after adjusting for demographic factors and PTSD. This is important because reports of functional impairment and the perceived ill health in personnel with physical symptoms indicate that they are not functioning optimally.
Several mechanisms could explain the increased physical morbidity in people with PTSD. The biological mechanisms suggested are cardiovascular reactivity, autonomic hyperarousal, disturbed sleep physiology, adrenergic dysregulation, immune dysregulation, enhanced thyroid function, and altered HPA activity . In addition to biological mechanisms, psychological correlates such as depression and poor health habits such as smoking and drinking can also result in increased physical morbidity.
This is a study of military personnel from a different cultural background to those in the USA or the UK. Social factors such as separation from home and family, cohesion and support from members of the unit, and acceptability by the community can modify stressful experience. These factors must be explored in future studies.
The strengths of this study are the large, randomly drawn sample of military personnel with high exposure to potentially traumatic events and the very high response rate. There are several limitations of this study. Self reports were used in the assessment, and this can result in underreporting of symptoms specially because military personnel may be reluctant to acknowledge the presence of symptoms. Personnel with multiple physical symptoms may also overreport symptoms. The study reports the presence of multiple physical symptoms rather than medically unexplained symptoms because no attempt was made to identify the etiology of symptoms. A cross-sectional study of this nature cannot establish causation. Future studies should assess the prevalence of symptoms before and after deployment to identify the symptom burden which can be attributed to deployment.