Methodological approach to depressive symptoms in fibromyalgia patients

Objective. Depression is a common comorbid condition in fibromyalgia (FM) and a major contributor to poor quality of life and disability. However, depression can be difficult to assess in patients with FM due to overlapping symptoms between the two conditions. This review aims to present the most used rating scales for depression in FM patients by discussing their potential drawbacks. Moreover, we aimed to discuss the possible approach to mood symptoms in FM patients according to the mood spectrum model. Methods. We included the main scales that have been used previously to assess depression in FM according to the literature data. Then, we reviewed the studies exploring the prevalence and the impact of sub-threshold mood symptoms on FM patients. Results. Rating scales for depression such as the Hamilton Rating Scale for Depression, the Hospital Anxiety and Depression Scale, the Center for Epidemiologic Studies Depression Scale, the Beck Depression Inventory, the Montgomery Asberg Depression Rating Scale and the Zung Self-Rating Depression Scale have been largely used. However, almost all these instruments could suffer from a criterion contamination bias by somatic symptoms of chronic pain patients. Many studies have shown a critical role of sub-threshold mood psychopathology on worsening quality of life, disability and pain in FM patients. Specific questionnaires (Mood Spectrum Self-Report [MOODS-SR]) for subsyndromal phenomenology have been validated and used also in patients with medical diseases. Conclusion. The need of a careful screening of depressive symptoms and of their proper management is primary in FM. In our opinion instruments like MOODS-SR are particularly suitable for screening FM patients because they allow to recognise also sub-threshold mood symptoms with minimal contamination by somatic conditions.