Signs of physical and emotional distress

The findings show that indoor air-related disability had various signs of distress. In Study II, the patients reported numerous signs of distress (physical, emotional, cognitive). Self-reports revealed prevalent insomnia-related symptoms and multi-site pain. These are also typical features in FSS (Eliasen et al. 2018; Mariman et al. 2013) and MCS patients (Blanco et al.

2016; Weiss et al. 2017), and are associated with work disability (Saltychev and Laimi 2018; Sivertsen et al. 2009). Our patients also reported work-related burnout in facets of physical, cognitive and emotional functioning. Job strain/burnout has been found to be a predictor of work disability (Salvagioni et al. 2017), and co-occurs with distress disorders such as impaired sleep, pain and anxiety (Ekstedt et al. 2006; Salvagioni et al. 2017). In the psychological

interviews of Study I, one third of the INT group described symptoms typical of depressive mood, sleeping problems, or anxiety. A previous population-based follow-up study has shown that individuals who later began to attribute annoyance to environmental factors reported even at baseline, more health complaints, higher levels of stress, strain and lack of recovery, as well as more dissatisfaction with their work situation and lower personal social support than those who did not develop such environmental attribution (Eek et al.

2010).

Negative beliefs and great concerns regarding the effect of indoor air exposures on health were prevalent among the patients in the clinical studies (Study I, II). The counseling of the INT group (Study I) revealed prevalent concerns of a serious disease or a loss of health (60%), and in some, fears had led to avoidance and restricted personal life (20%). All the patients in Study II reported considerable health concerns related to indoor air environments. In previous findings, concerns regarding indoor air-related health hazards have been common (Bluyssen et al. 2016; Redlich et al. 1997). In general, health concerns attributed to environmental factors have been highly prevalent, and are typically encountered in IEI (Baliatsas et al. 2015b; Van den Bergh et al.

2017a). Health concerns have positively associated with perception and the amplification of the physical symptoms of IEI and these health worries may contribute to the development of IEI (Bailer et al. 2008a; Van den Bergh et al.

2017a). When an individual perceives certain environmental factors as health hazards, stress reactions can manifest as multiple organ symptoms (Van den Bergh et al. 2017a). The role of health anxiety and illness worries in FSS is also well established (Henningsen et al. 2018). Elevated concerns may predict the development of health complaints and lead to higher symptom reports (Rief and Broadbent 2007; Watt and Stewart 2000). Negative illness perceptions have also been associated with lower physical and mental health (Frostholm et al. 2007), as well as physical symptoms accompanied by health anxiety and considerable concerns (Tomenson et al. 2013). A pronounced high health threat can be subjectively valid even if its connection to the perceived source is tenuous (Bailer et al. 2008a; Brown 2004; Rief and Broadbent 2007).

Our results support the hypothesis that individuals’ expectations of the symptoms and adverse effects of certain surroundings can induce and maintain health complaints (Van den Bergh et al. 2017a). It has been suggested that central mechanisms (central sensitization) play an essential role in the development and maintenance of adverse reactions. Dysfunctional cognitions may increasingly enhance the reactions to actual or anticipated stimuli (Bell et al. 1996b; Henningsen et al. 2007, 2018; Kipen and Fiedler 2002; Rief and Broadbent 2007; Van den Bergh et al. 2017a; Yunus 2007) (see Figure 3, Section 2.3.6). Further, increasing evidence proposes that expectancy and nocebo mechanisms are critically involved in the development of symptoms and in linking them to specific environmental cues (Martens et al. 2018; Van den Bergh et al. 2017a). The persisting illness attribution to environmental factors is associated with intensity of symptoms (Van Dongen et al. 2014). The

perception of a threat stimuli can lead to CNS activation including both early autonomic reactivity and later prefrontal responses to consciously attended fear and avoidant coping (Hofmann et al. 2012). Awareness of symptoms together with concerns can feed further into a vicious circle of adverse consequences, and the condition becomes worse, with subsequent chronification (McEwen 2007; Rief and Broadbent 2007; Van den Bergh et al.

2017b).

The physiological stress and arousal indicators in Study II showed insufficient recovery in the HRV recordings and raised evening cortisol levels in six (out of 10) patients, but there no specific profile emerged in the findings.

Physiological arousal (Brosschot et al. 2006) due to stress and persevering illness cognition can be mediated and modulated by various complex mechanisms, such as the regulation of the ANS, HPA axis, and immune system (e.g. proinflammatory cytokines) (Yunus 2015). According to previous findings, physiological measurements do not necessarily correspond with symptoms and their severity (Van den Bergh et al. 2017b). In addition, the literature has shown similar inconsistent findings concerning HPA axis activity among individuals with clinical burnout (Grossi et al. 2015). ANS recordings have typically been used as arousal indicators in provocation studies. For example, a Swedish study of 18 individuals with MCS found that those with MCS expressed higher pulse rate and lower pulse rate variability as ANS responses during chemical exposure than healthy controls, as well as greater perceived odor intensities, more unpleasantness from the exposure, and increasing symptoms (Andersson et al. 2016).

Overall, the cognitive and emotional processes of dysfunctional illness perceptions and illness worries are associated with high symptom reports in IEI (Bailer et al. 2008b; Staudenmayer 2001; van Dongen et al. 2014), FSS (Bailer et al. 2008b; Frostholm et al. 2007; Rief and Broadbent 2007) as well as in chronic diseases such as asthma (Horne and Weinman 2002; Lehrer et al. 2002). A plausible explanation is that mechanisms regulated by CNS, central sensitization, can act either with or without verified disease (Yunus 2015). For example, psychological mechanisms, i.e. cognitive and emotional processes, have shown to mediate asthma exacerbation (e.g. Van Lieshout and MacQueen 2008), and are involved in the reporting of respiratory symptoms (Selinheimo et al. 2018), which may result in an overestimation of the severity of asthma (Selinheimo et al. 2018; Van Lieshout and MacQueen 2008). The differentiation of symptoms and their different mechanisms is essential for effective management strategies (Hubley et al. 2016; Yunus 2015).

Recognition of the underlying signs of distress enables the use of various stress-reducing interventions in the management of disability.

6.1.5 CO-OCCURRENCE OF SOMATIC AND PSYCHIATRIC DISEASES