Understanding symptom-based disorders – how we think about and talk about them
Symptom-based disorders (SBDs) such as fibromyalgia, functional neurological disorder (FND), irritable bowel syndrome and chronic fatigue syndrome present a significant challenge to traditional models of healthcare delivery. These conditions are characterised by persistent symptoms – pain, fatigue, sensory, motor or cognitive dysfunction – that are not fully explained by identifiable structural pathology. Estimates suggest that up to 30% of LTCs are accounted for by SBDs, and similarly, up to 30% of primary care consultations involve symptoms without a clear organic cause.
11 This has substantial implications for healthcare utilisation and patient experience.
Despite their prevalence, SBDs remain poorly understood. They are not singular entities but reflect a convergence of biological dysregulation, psychological factors and social context.
12 Neuroimaging studies in FND and chronic pain syndromes reveal altered brain network activity, particularly in regions governing attention, emotion and sensorimotor integration.
13 These changes are functional, representing neuroplasticity, and not degenerative. The nervous system is inherently adaptive; its calibration is influenced by environmental inputs, behavioural patterns and internal states. It is therefore plausible – and increasingly evidenced – that persistent symptoms may arise from maladaptive processing rather than fixed pathology. Importantly, these changes are modifiable, highlighting the potential for recovery through targeted rehabilitation and behavioural interventions.
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This distinction – dysregulation versus degeneration – is critical. Medical education has traditionally focused on disease models rooted in structural pathology. However, SBDs challenge this paradigm, requiring clinicians to engage with multifactorial systems involving stress physiology, sleep disruption, microbiome–host interactions and epigenetic influences.
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Understanding this dynamic reframes how we talk about these conditions. Language matters. Terms such as ‘degeneration’ imply irreversible decline, whereas ‘dysregulation’ suggests potential for recalibration and recovery. This shift supports a more hopeful, person-centred narrative and aligns with emerging rehabilitative models of neuroplasticity and functional optimisation. It also helps avoid the damaging overmedicalisation of distress, which can risk a perceived attribution of blame for symptoms.
15 Training the body – through movement, graded activity and sensory retraining – is not merely symptomatic management, but a way to recalibrate neural circuits and restore function. This perspective encourages patients to engage actively in their recovery, supported by multidisciplinary teams that validate their experience and promote self-efficacy.
