Diagnosis relies on symptom-based diagnostic criteria that lack objectivity

The gap

Evidence profile

Sourced from the future work and recommendations and limitations section of the source papers, classified as general, spanning 3 journals.

Supporting evidence — 3 representative gaps

• The impact of opioids on cognitive abilities – balancing pain management and cognitive preservation: A narrative review (2026) · Annales Academiae Medicae Silesiensis · doi

  neurotoxicity, opioid-induced to particularly in the context of chronic use [26,27]. The discussion of neuroinflammation also leads to the complex topic of opioid-induced hyperalgesia (OIH). This is a paradoxical state where opioids, meant to relieve pain, actually begin to increase a patient’s pain sensitivity. Although OIH is a recognized phenomenon, there is still considerable debate about its true prevalence and importance in cancer-related pain [43]. This presents a major diagnostic challenge for clinicians. When a patient’s pain worsens, is it because the disease is progressing, has the patient developed tolerance, or is it OIH? Making the right call is critical because the treatment for OIH is counterintuitive: it often requires reducing the opioid dosage, not increasing it. A critical element of the acknowledgment that the observed clinical picture in patients is the result of an interaction between two powerful factors: the pain itself and the action of opioids. As shown by current meta-analyses [34] and cohort studies [35], chronic pain per se is an independent risk factor for cognitive decline. The magnitude of this phenomenon is striking: it not only leads to a measurable, 9% faster decline in memory performance, but it may also slightly elevate the long- -term risk of developing dementia [35]. This may reflect the structural brain changes visible in neuroimaging studies, which document atrophy in areas responsible for attention, executive control, and memory encoding – particularly the medial prefrontal cortex and cingulate gyrus – consistent with the concept of cognitive resource competition [36]. Understanding this fact is essential for the differential diagnosis of cognitive deficits, allowing clinicians to distinguish symptoms stemming from the underlying disease, which themselves can more than double the risk of cognitive impairment from the iatrogenic effects of pharmacotherapy [37]. The clinical expression of this interaction is further evidenced by objective behavioral data, such as poorer performance on decision-making tasks among patients experiencing pain [38], reinforcing the need for integrated cognitive-pain assessment. The impact of opioids on cognitive functions is not uniform and can shift over the course of treatment. While some cognitive effects in non- -cancer pain after drug discontinuation [13], the picture is complicated by the reversible can be 37 M. Mierniczek et al.: OPIOIDS AND COGNITIVE FUNCTION [29] study development of tolerance. A classic clinical example is tolerance to sedation: many patients who are initially drowsy for the first few days of therapy find that this effect wears off over time. This adaptation can be beneficial for a patient’s

  generalfuture work
  Keywords: pain cognitive opioids patient opioid tolerance clinical patients risk induced particularly chronic leads phenomenon cancer
• Real-world patterns of analgesic combination therapy and their associations with pain intensity and treatment modification in patients with chronic non-cancer pain: A retrospective observational study (2026) · Pakistan Journal of Pharmaceutical Sciences · doi

  management of neuropathic pain: An overview and literature update. Mayo Clin. Proc., 85(3 Suppl): S3– 14. the Eriksen J, Sjøgren P, Bruera E, Ekholm O and Rasmussen NK (2006). Critical issues on opioids in chronic non- cancer pain: an epidemiological study. Pain, 125(1-2): 172–9. Farrar JT, Young JP, Jr., Lamoreaux L, Werth JL and Poole MR (2001). Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale. Pain, 94(2): 149–158. Finnerup NB, Haroutounian S, Kamerman P, Baron R, Bennett DLH, Bouhassira D, Cruccu G, Freeman R, Hansson P, Nurmikko T, Raja SN, Rice ASC, Serra J, Smith BH, Treede RD and Jensen TS (2016). Neuropathic pain: An updated grading system for research and clinical practice. Pain, 157(8): 1599– 1606. Gatti A, Longo G, Sabato E and Sabato AF (2011). Long- term controlled-release oxycodone and pregabalin in the treatment of non-cancer pain: An observational study. Eur. Neurol., 65(6): 317–322. Gilron I, Bailey JM, Tu D, Holden RR, Jackson AC and Houlden RL (2009). Nortriptyline and gabapentin, alone and in combination for neuropathic pain: A double-blind, randomised controlled crossover trial. Lancet, 374(9697): 1252–61. Gilron I, Baron R and Jensen T (2015). Neuropathic pain: Principles of diagnosis and treatment. Mayo Clin. Proc., 90(4): 532–45.

  generalrecommendations
  Keywords: pain neuropathic mayo clin proc chronic cancer clinical baron jensen sabato controlled treatment gilron management
• Fibromyalgia: A Multifactorial Pain Disorder (2026) · International Journal of Molecular Sciences · doi

  diagnosis relies on symptom-based diagnostic criteria that lack objectivity, - direct histopathological evidence in FM remains limited, - small fiber neuropathy is likely to characterize a specific subset of FM, rather than being a universal feature, - opioid use can lead to tolerance development and opioid-induced hyperalgesia, - the study did not reveal clear lesions that would explain the patients' complaints of pain

  generallimitations sectionevidence 5/5
  Keywords: diagnosis relies symptom-based diagnostic criteria lack objectivity direct

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