This epidemiological study shows that PPS are a common feature in patients suffering from GAD, especially in those presenting comorbid MDD [8
]. In this post hoc analysis, the presence of PPS was clinically and statistically significantly related to worse patients' functioning, productivity, and quality of life regardless of the patient's disease severity, age, gender, or comorbidity. The magnitude of this association between the presence of PPS and functioning impairment has proven to be relevant and persists even in the absence of comorbid MDD. Thus, the presence of PPS in patients with GAD, with or without comorbid MDD, was shown to be strongly associated with functional impairment in patient's work, social, and family lives. Hence, it is highly relevant for the physician to assess patients for PPS when evaluating for and treating GAD, regardless of the presence of comorbid MDD. A comprehensive evaluation of the role of these symptoms in a patient's ability to perform daily activities could improve the management of GAD and ultimately the patient's outcome.
The present study is the first to report the results of an assessment of functional impairment related to the presence of PPS in a large sample of primary care patients with GAD. The few similar published studies to date were either focused on community samples [33
] or included patients suffering from any anxiety disorder other than GAD [34
]. Our results are consistent with these previous studies, in which pain symptoms were reported to be associated with poorer functioning in patients suffering from social anxiety and post-traumatic stress disorder [35
] as well as in a community sample diagnosed with any anxiety disorder [33
]. However, contrary to the results of Means-Christensen et al. [35
], our study shows a clear association between PPS and a diagnosis of anxiety disorder (GAD in our study) that is not mediated by the presence of comorbid MDD. This could be due to the differences in patient samples and designs of both studies.
It is known that GAD is associated with clinically significant impairments in social, occupational, and/or family functioning [1
]. As reported previously [1
], several factors that contribute to greater functional impairment were determined, including the presence of psychiatric or medical comorbidity, age, patients' disease severity, and being female. However, none of the available studies on GAD focused on the effects of PPS on functional impairment. The current study contributes to the understanding of the specific role of such pain symptoms in worsening the functioning in patients with GAD. The presence of PPS is associated with a statistically and clinically significant impairment in patients' functioning, productivity, and quality of life, regardless of patients' disease severity, age, gender, or MDD comorbidity. In regard to productivity, patients with PPS had substantially more underproductive days per week compared to those without PPS. As expected, the presence of comorbid MDD was associated with worse productivity [38
Several clinical implications could arise from these study results; PPS are frequent and significantly interfere with patients' family, social, and work activities. In order to ensure effective management of patients with GAD, it would be desirable to pay special attention not only to the typical symptoms of the disease but also to these PPS. Therefore, clinicians may routinely evaluate the extent to which symptoms impact patients' ability to perform well in a range of activities or areas. However, this task may not be as easy as it appears, given that functioning and pain symptoms are not commonly or systematically measured during the management of the disease. Also, primary care physicians do not always make the association between pain symptoms and mental disorders; that is, they tend to associate pain symptoms more with a somatic disease rather than a mental disorder [31
]. Primary care physicians may have to bear in mind that PPS are very commonly associated with both depression [39
] and anxiety [8
]. Moreover, they should be aware that that their presence could be associated with poorer treatment outcome and be a barrier to an adequate diagnosis of the disease [42
In accordance with current knowledge, this study found that GAD was not recognized by the physician for a large proportion of primary care patients, thus a large percentage of patients did not receive appropriate treatment for the disease [46
]. Among the treatment options, only one-third of patients (or even fewer) was receiving antidepressant treatment, while benzodiazepines were being used predominantly. Awareness or recognition and adequate treatment of GAD would be important, particularly in primary care settings. The fact that patients with emotional distress report physical or somatic symptoms more often than psychological symptoms [47
] could be a contributing factor for the under-recognition rates found in this study [8
]. In order to improve the recognition of GAD in primary care, physicians should see these somatic symptoms as a high-risk factor not only for depression, but also for anxiety, especially if the symptoms are multiple and medically unexplained [42
In the light of the study findings, primary care physicians should seek for an effective management of these PPS, and closely monitor the patients' improvement, so in this way the chances of functional recovery would be increased.
The present analysis has several limitations; the main limitation is that the analysis is focused mainly on correlations and associations, but does not provide any causal relationships. The results of the analysis cannot rule out possibility of patients' recall bias associated with the condition of underproductive days. However, the presence of a control group mitigates that bias. It could be argued that the use of categorical research-based criteria, such as the DSM-IV, is not useful in clinical practice because it artificially separates depression from anxiety. However, their use in this study is recommended in order to fully understand the specific role of pain symptoms in anxiety that is not mediated by the presence of MDD. Moreover, using standard criteria may allow further comparison with other research. The results should be not generalized to patients treated by psychiatrists, inpatients or other populations. Controls were selected based on the HADS-A subscale and total score on the HADS, and no structured interview was carried out. However, negative predictive values for selected cutoff points are 92% (HADS-A) and 78% (HADS) [48
]. The major strength of this analysis is that it is the first time the specific role of PPS in functional impairment and their influence on underproductivity and quality of life was analyzed in a large sample of primary care patients with GAD, with or without MDD, by means of a controlled-design study. The naturalistic study design and the representativeness of the sample allow the generalization of the results to primary care patients with GAD. The presence of a control group of patients without MDD or GAD allows a more conclusive and comprehensive interpretation of the results.