The relationship between affect balance style and clinical outcomes in fibromyalgia

Affective balance, relative levels of negative affect (NA) and positive affect (PA), better describes emotional functioning than NA or PA alone. Affect balance styles and their relationship to clinical outcomes were compared between patients with fibromyalgia (FM) and controls.

FM patients (n = 79) were compared with patients with other medical conditions (controls; n = 92). Patients underwent a physical examination, completed questionnaires, and were screened for clinical disorders such as depression, with diagnoses confirmed by structured interview. Affect balance style categories were calculated as follows: healthy (high PA/low NA), low (low PA/low NA), reactive (high PA/high NA), and depressive (low PA/high NA).

Compared with controls, FM patients had lower levels of PA (P = 0.0031; P values are adjusted for multiple testing), higher levels of NA (P = 0.0061), lower levels of functioning (P < 0.0001), and more clinical disorders (P = 0.0031). Groups differed regarding affect balance style (P = 0.0061), with FM patients being more likely than controls to be categorized as depressive (odds ratio 5.60) and reactive (odds ratio 3.81). FM patients and controls with reactive and depressive affect balance styles reported poorer functioning (P < 0.0001) compared with patients with healthy affect balance style. Finally, there was an association between affect balance style and psychiatric comorbidity (P < 0.0001), with patients with depressive and reactive affect balance styles having a 9.00 and 4.75 odds ratio, respectively, of having psychiatric comorbidity compared with patients with healthy affect balance style.

Depressive (low PA, high NA) and reactive (high PA, high NA) affect balance styles were predominant in FM patients and related to poor functioning and psychiatric comorbidity.