This randomized controlled trial aims to evaluate the effect of a single session intervention based on a nature-based stimulation program in patients with fibromyalgia

All participants will continue to receive their usual pharmacological treatment as previously established by the Andalusian Public Health System. The intervention will comprise interaction tasks with biotic and abiotic agents for 30 minutes.

Inclusion Criteria:

• Diagnosis of fibromyalgia syndrome (ACR criteria 2016).
• Chronic widespread musculoskeletal pain symptoms (>1 location using the Widespread Pain Index).
• High-intensity pain (VAS ≥ 4), at least 3 days a week for the previous 3 months.
• If currently taking analgesic or psychotropic medications, they had to be stabilised for four or more weeks before the study enrolment
• Over 18 and less than 65 years old (labour active).
• Ability to speak and understand English or Spanish.

Exclusion Criteria:

• Acute or temporal pain
• Severe cognitive impairment, detected by the Mini-Mental State Examination (score <24 out of 30 points)
• Severe mental disorders in acute phase or symptomatic phase
• Behavioural alterations as this may interfere in their participation
• Severe intellectual disability
• Other severe or medically unstable diseases interfering with the project participation
• Co-occurrence of neuropathic pain
• Other disorders that may cause pain
• Pregnant or breast-feeding
• Drug abuse within the past year.