Introduction: Chronic rhinosinusitis (CRS) impairs the quality of life similar to diabetes or heart disease. In the USA, 15% of the population suffers from this condition, and it is responsible for 13 million visits to a physician and 2 million hospitalizations each year. CRS was the most common diagnosis of all the head and neck diseases for 361 veteran returning from the Gulf War. Posttraumatic stress disorder (PTSD) is the fourth most frequent psychiatric diagnosis in the USA, affecting 10% of males and 18% of females. The vast majority of PTSD patients in Croatia are diagnosed with combat-related PRSD, which is clinically more severe than the PTSD caused by other forms of trauma. Given that both diseases are frequent in Croatia and other developed countries, the expected comorbidity of PTSD and CRS is great. The etiology of CRS is multiple, with different inflammatory mechanisms that can lead to the development the disease. The pathophysiology of the disease is intertwined with numerous predisposing factors such as allergies, nonallergic hyperactivity, asthma, ciliary dyskinesia, and anatomic deformations. PTSD is a psychiatric disorder caused by a prior traumatic event. There are three main symptom clusters of PTSD: 1. (1) persistent re-experience of the event that caused the trauma; (2) persistent avoidance of stimuli that remind one of the event; and (3) increased emotional arousal. The pathoanatomic background of the aforementioned symptoms is a disorder in the synthesis of neurotransmitters in the hippocampus and amygdala. CRS is a disease that is diagnosed on the basis of subjective symptoms, which means that only anamnesis and clinical examination are needed for the diagnosis. An objective method like computed tomography is widely accepted, but it is insufficient in monitoring a patient’s condition because it correlates poorly with subjective symptoms. The scoring of CT results by Lund–Mackay provides the best correlation of CT results and subjective sinonasal symptoms; however, this correlation is lost with nonnasal sinonasal symptoms, including pain. Objectivization is also possible according to endoscopic grading, which is widely accepted, but it is dependent on the physician’s subjective assessment. Due to these weaknesses in these objective methods, evaluation by subjective tests provides the most valuable information about the course of the disease, therapy success, and the effects of the disease on each patient’s quality of life. Pain and fatigue are the two most common nonnasal sinonasal symptoms. With the detailed diagnosis and treatment of patients with facial pain as the obstinate symptom, we most often eliminate CRS as the cause of pain, and reach a neurological diagnosis. So far, the effect of PTSD on chronic orofacial pain was identified, it has also been identified that males with PTSD are not the only ones who exhibit intense chronic pain; their spouses also report experiencing pain, often in the form of headaches. With patients who report fatigue, it should be taken into consideration that 46% of patients with chronic fatigue syndrome (CFS) suffer from nonallergic chronic rhinosinusitis, and that 26% of patients with CRS suffer from chronic fatigue syndrome. The fact that the main pathophysiological changes of PTSD and CFS take place in the central nervous system (particularly in the amygdala and hypothalamus) was the starting point for our hypothesis that enhanced sensitivity to facial pain, systemic sensitivity to pain, disturbed sleep and fatigue worsen the results of sinonasal tests and quality of life tests in patients with PTSD and CRS. The correlation of CFS and CRS is well researched; the deterioration of symptoms in comorbid conditions is interpreted as having systematic nociceptive dysfunction that is not conditioned by local inflammatory response in the sinonasal area; rather, this pain arises from the central nervous system and the opioid system of the posterior horns of the spinal cord. It is also known that PTSD and CFS symptoms are similar to those noted in many “wartime” syndromes (soldier’s heart, shellshock, Gulf War syndrome) and “peacetime” syndromes (fibromyalgia, somatization disorders, and multiple chemical sensitivities). Objective and hypotheses: The aim of our study is to determine the influence of posttraumatic stress disorder symptoms on chronic rhinosinusitis and the quality of life and pain in the orofacial area. The aim is also to explore the connection between the parameters of quality of life and orofacial pain with CT findings of paranasal cavities in patients with CRS and CRS and PTSD. The hypothesis is that due to increased sensitivity to pain, disturbed sleep and fatigue in patients that also suffer from PTSD and CRS, there is an additional deterioration of the CRS symptoms. Patients with mild forms of the CRS and PTSD as comorbidity are to be classified in the group with severe CRS, which exposes them to the risk of additional and unnecessary therapeutic and diagnostic procedures; and secondly, in patients with the symptoms of CRS that do not respond to treatment, it is necessary to revise the diagnosis, and one of the differential diagnosis is the PTSD. Respondents and methods: The study included 30 patients with chronic rhinosinusitis and 30 patients with post-traumatic stress disorder and chronic rhinosinusitis. Chronic rhinosinusitis was diagnosed on the basis of diagnostic guidelines from the European Position on Rhinsinutis and Nasal Polyps (EPOS). The criteria are that the disease lasts longer than 12 weeks, the existence of two or more symptoms, one of which must be a blockage / obstruction / congestion or nasal / postnasal secretion. Other possible symptoms include pain or pressure in the face and smell disorder. The diagnosis was completed with endoscopic findings and CT testing according to Lund Mackay, where the inclusion criterion was a score equal or greater then 5 on the worse side. Excluded were patients who had been on systemic corticosteroids a month prior to study entry, patients with acute respiratory inflammation, or any systemic disease that affects the protocol of theresearch. Posttraumatic stress disorder was diagnosed on the basis of three main groups of symptoms that characterize PTSD: 1. (1) persistent re-experience of the event that caused the trauma; (2) persistent avoidance of stimuli that remind one of the event; and (3) increased emotional arousal. Both groups filled the SF-36, SNOT-22 and VAS questionnaire. SNOT-22 (the Sino-Nasal Outcome Test 22) questionnaire evaluates the severity of sinonasal and some general symptoms and their influence on the quality of life of patients. The relationship between the questionnaire and CT testing was analyzed by regression analysis. Test results of PTSD / CRS and the CRS groups of patients were compared with a Student's t-test. χ² test was used to test the resulting differences in values of qualitative variables. Results: The average age of respondents was 50 years, while the youngest participant was 22 and the oldest 78 years. Groups of respondents with the PTSD and CRS diagnosis achieved statistically significant differences on all measures of the SF36 questionnaire. Respondents diagnosed with PTSD achieved significantly higher scores on the total score of the SNOT-22 questionnaire then the patients diagnosed with CRS: PTSD/KRS 66.2 and CRS 44.8 (t=5.658; p<0.01). Respondents diagnosed with CRS showed greater problems with clogged nose (t = -2.834, p <0.01, and greater loss of smell and taste (t = -2.625; p <0.05). While respondents who have a diagnosis of PTSD / CRS statistically significantly differ from patients diagnosed with CRS, in a way that they show greater problems with dizziness, pain or pressure in the face. They also show greater difficulty falling asleep, have more problems with waking up at night, and lack of good sleep. Respondents with PTSD / CRS often state that they wake up tired, that they are tired, they also give higher estimates of reduced work efficiency, pronounced lack of concentration, helplessness, anxiety, irritability, sadness and confusion. All these differences were determined by a t-test for independent samples with a p<0.01. When we make a comparison of CRS and PTSD/CRS respondents considering the division into two subscales of the SNOT-22 test, so that the questions from 1-12 constitute the scale of "physical symptoms" and from 13-22 the scale "emotions, fatigue, sleep", respondents with a diagnosis of PTSD/CRS and CRS do not differ on the outcome of the subscale of physical symptoms (t = 0.271; p> 0.05), while on the subscale of emotion, fatigue and sleep respondents diagnosed with PTSD/CRS achieve significantly higher scores than respondents with a diagnosis of CRS (t = 7.842; p <0.01). When the CRS and PTSD/CRS groups are compared on the VAS scale only by using nasal questions (2, 3, 4, questions from the VAS questionnaire) then the respondents diagnosed with PTSD/CRS and CRS differ significantly given the nasal questions on the VAS scale (chi-square = 7.051; p <0.05). The largest number of patients diagnosed with CRS are categorized as severe (N = 20), while only one respondent was in the category of mild. For respondents with a diagnosis of PTSD, most of them are in the medium category (N = 17). Pain constitutes a special group of statistical processing. First we separated all the questions in the questionnaire related to pain; SNOT question no. 12, VAS questions number 1, 5, 7, questions SF-36 SF-07 and SF-08. Afterwards, there was a divisions to high and low perception of pain by separating the respondents that had results of questions about pain greater than the median for those questions (median = 20), thus obtaining two groups with "high perception of pain" and "low perception of pain". It was found that 80% of respondents in the PTSD/CRS group have a high perception of pain, while 80% of the respondents in the CRS group have a low perception of pain. The respondents diagnosed with PTSD/CRS differ with respect to the amount of pain perception in the result on the SF-36 pain scale, and the overall Lund Mackay result. The respondents with a higher perception of pain achieve significantly higher scores on the pain scale of the questionnaire SF-36 (t = -4.953; p <0.01). The respondents with high perception of pain also achieve higher overall Lund Mackay scores (t = -2.776; p <0.05). Macropathological differences: In the CRS group 16 patients had nasal polyps, 14 did not, in PTSD/CRS group 12 patients had nasal polyps and 18 did not. Discussion Results suggest that symptoms of obstruction in patients with a high Lund Mackay score draw attention to the sinonasal area and with excessive focusing of attention interfere with emotional interpretation of pain. There is a positive feedback between the sensory, affective and cognitive components of psychogenic and chronic pain, where any component can induce and maintain chronic pain. This creates a model of mutually supportive pain and PTSD. With mechanisms of dissociation, anxiety sensitivity and a model of mutually supportive chronic pain, pain becomes a leading symptom in patients with PTSD/CRS. Psychogenic and psychosomatic pains are here hardly distinguishable from each other even more so as one does not exclude the other and they can complement each other. Respondents diagnosed with PTSD achieve significantly higher scores on the total score of the SNOT-22 questionnaire then the patients diagnosed with CRS. SNOT-22 shows a clear division between the two diagnoses; subjects diagnosed with CRS show greater difficulties with nasal obstruction and loss of smell and taste, while subjects with a diagnosis of PTSD show greater difficulties with dizziness, pain or pressure in the face, and have difficulties with falling asleep, waking up at night, and lack of sleep. Also, they wake up tired, have reduced work efficiency, have problems with concentration, they are disturbed, sad and helpless. The study, which examined the impact of depression and anxiety in the CRS has also found a great impact of both diseases on the overall SNOT-22 score, but also a strict division of influence; depression has increased the nasal symptoms scores, and anxiety has increased the scores related to emotions, fatigue and sleep. Our results confirm the results of that study, and PTSD as an anxiety disorder effects the issues related to fatigue, emotions and sleep (in SNOT-22 from 12 to 22). Study of the ENT Department of the University Clinical Hospital Center "Sestre Milosrdnice" examined the impact of stress on the symptoms of CRS. Stress has been investigated by the Measure of Perceived Stress scale (MPS), an inclusion criterion for the CRS was a VAS score equal to or greater than 3 in the two main sinonasal symptoms. The respondents with higher stress scores also had higher scores on the SNOT-22 test. In this context our group confirms the trend, where the PTSD diagnosis was one of the end results of stress deterioration, and as such has deteriorated theSNOT-22scores. Results of the SF-36 test in all subscales were worse in patients with PTSD/CRS. If patients have a stress-induced glucocorticoid resistance, then the patients are at risk of unnecessary diagnostic and therapeutic procedures, and the opposite, in CRS patients who do not respond to therapy, it is necessary to revise the diagnosis and one of the possible comorbidity diseases is PTSD. The pain itself in the PTSD/CRS group is a part of the emotional component of the overall form of chronic psychogenic pain, where the pain is caused by turning emotional attention to sinonasal area obstructed by polyposis or thickened mucous membranes (high Lund Mackay score). This differs PTSD from the chronic fatigue syndrome in which there is a feeling of nasal obstruction with no real objective indicators of obstruction. Our results suggest the benefits of surgery for PTSD/CRS patients with high scores on the issues of pain, in which the Lund Mackay score is high because re-enabled nasal patency could reduce pain. The emphasis is on the operative therapy, because if there is a stress-induced corticosteroid resistance, treatment with corticosteroids would not give any benefits. A similar pattern of symptoms with comorbidity of PTSD and CRS is also shown by chronic fatigue syndrome, fibromyalgia and multiple chemical sensitivity. Our study confirms the results of previous studies that have shown a stress pattern and anxiety on the SNOT-22 test; increased results non-nasal symptoms; fatigue, emotions and sleep. Depression has a different pattern as it worsens the sinonasal symptoms. One can consider that the SNOT-22 in questionable diagnostic cases should be viewed through two subscales, while the SF-36 can also be helpful, it also exacerbates the results of pain subscales and subscales that along with physical requirements also demand mental engagement. Using the quality of life tests we can diagnose the comorbidity of CRS and PTSD because patients with comorbidity show significantly worse scores on emotion subscales of sleep and fatigue on the SNOT-22 test, report more pain in questions about pain in all three used tests and show a better result on the VAS scale of nasal symptoms. Tests of subjective symptoms and quality of life components reverse the paradigm of modern medicine in which technological advances in diagnostics and their use is imperative. Diagnostic tests of the quality of life and symptoms return us to an archaic way of not only diagnosis but also of understanding the well-being of treatment. Archaic here is not in a negative context because it brings us back to the fundamental principles of Hippocrates' understanding of the health of an individual. The questionnaires instrumentalize the anamnesis and put the focus on real patient problems in the context of the overall social experience. Tests of subjective symptoms and quality of life components help in the diagnosis and monitoring of diseases as a simple, cheap and effective diagnostic tool. Conclusions Based on the results of this research we can arrive to the following conclusions. Patients with chronic rhinosinusitis and posttraumatic stress disorder have significantly lower quality of life, as measured by the SF-36 test, then the patients with chronic rhinosinusitis. The division of te SNOT-22 test on two subscales has diagnostic value in distinguishing between chronic rhinosinusitis and chronic rhinosinusitis and comorbid posttraumatic stress disorder because patients with chronic rhinosinusitis and posttraumatic stress disorder had significantly worse results on the SNOT-22 test; at the same time there is a clear division: respondents diagnosed with CRS/PTSD and the CRS do not differ in the result on the subscales of physical symptoms, while on the subscales of emotion, fatigue and sleep respondents diagnosed with CRS/PTSD achieve significantly higher scores than subjects with diagnosed CRS. Obstruction of the paranasal sinuses and nasal cavities is associated with a stronger pain in patients with CRS/PTSD because respondents diagnosed with CRS/PTSD with high perception of pain also achieve higher overall Lund Mackay scores. This would, due to corticosteroid resistance induced by stress, make surgery of the nasal obstruction a treatment of choice in this group of patients. If for diagnosing and determining the disease severity we use the VAS scale, which along with questions about sinonasal symptoms has questions about general health and symptoms, then there is no statistically significant difference between the CRS and PTSD/CRS patients. If we use a VAS scale with only nasal symptoms then the groups are statistically different, CRS patients are mostly classified as severe form of disease and PTSD/CRS as medium severe form of disease. Based on the VAS scale, SNOT-22 test and SF-36 test, therapeutic options in patients with poor results can be determine more precisely because the PTSD/CRS patients are at risk of unnecessary diagnostic and therapeutic procedures aimed only at treating the CRS. On the contrary, in CRS patients who do not respond to therapy, it is necessary to revise the diagnosis and one of the possible diseases of comorbidity is PTSD.