Discounting seems the most toxic dimension of invalidation in fibromyalgia: a cross-sectional analysis.

Invalidation, both discounting (overt negative social responses) and lack of understanding (absence of positive social responses), is a common problem in fibromyalgia. The 'Fibromyalgia Imbalance of Threat and Soothing Systems' (FITSS) model indicates that different neuropsychological processes may underlie these two components of invalidation. Guided by this model, the aim of the current study was to clarify the differentiation between these two components of invalidation by examining their association with fibromyalgia severity, anxiety, and depression. This cross-sectional study included the Illness Invalidation Inventory (3*I), the Fibromyalgia Impact Questionnaire (FIQ), and the Hospital and Depression Scale (HADS). Demographics of the 280 respondents with fibromyalgia were: mean age 42.6 ± 11.8 yrs., 95% female, mean FIQ score 59.1 ± 15,5, possible or probable cases of anxiety and depression, 49% and 42%, respectively. Regression analyses revealed that discounting was associated with severity of fibromyalgia (t = 4.10, β = 0.34, p <.001), anxiety (t = 3.50, β = 0.29, p <.001) and depression (t = 3.64, β = 0.30, p <.001) symptoms. Neither lack of understanding (-1.62 ≤ t ≤.10, -0.13 ≤ β ≤ 0.01, p ≥ 0.11) nor the interaction of discounting and lack of understanding (-0.19 ≤ t ≤ 1.10, -0.01 ≤ β ≤ 0.07, p ≥ 0.27) was related to any of the outcome variables. The total model accounted for 8.8%, 5.3%, and 8.3% (adjusted R