In the sustainable development goals (SDG) context of seeking universal health coverage, the expanding gap between the supply of specialized and primary providers of headache-related health care on the one hand and the care needs of the very large number of people affected by headache on the other is a formidable but not insoluble public-health challenge. Structured headache services provide a cost-effective framework for provision of care but may still be overwhelmed by demand. Community pharmacists are an underutilized resource, potentially well able to provide the solution. This collection aligns with UN SDG-3 (Ensure healthy lives and promote well-being for all at all ages), and more specifically with SDG-3.8 (Achieve universal health coverage ..., access to quality essential health-care services and access to safe, effective, quality and affordable essential medicines ... for all). The collection may include reports (especially comparative studies) on current pharmacy practice (scope, responsibilities and regulatory and other restrictions) relevant to headache care in countries worldwide — especially, but not restricted to, low and lower-middle-income countries; studies of pharmacists' knowledge and understanding of headache disorders and their management, theoretically argued proposals for change that, through educational initiatives, expansion of community pharmacists' scope of practice or by other means, might relieve strained headache-care systems; and studies of workload-shifting in headache care from medical to community pharmacy services (economic evaluations, theoretical or empirical assessments of benefits versus harms, and reports of pilot implementations either in headache care or in other therapeutic areas that might be pathfinders for headache care).

This Collection supports and amplifies research related to SDG 3, Good Health & Well-Being.

All submissions in this collection undergo the journal’s standard peer review process. Similarly, all manuscripts authored by a Guest Editor(s) will be handled by the Editor-in-Chief. As an open access publication, this journal levies an article processing fee (details here). We recognize that many key stakeholders may not have access to such resources and are committed to supporting participation in this issue wherever resources are a barrier. For more information about what support may be available, please visit OA funding and support, or email OAfundingpolicy@springernature.com or the Editor-in-Chief.

The recurrence and associated clinical features of headaches are significantly affected by circadian rhythms and internal biological cycles in our bodies. Changes in the operation of our hypothalamus master clock and the periodic release of hormones due to genetic predisposition are likely to influence the cyclical manifestation of headache pain. There exists a bidirectional association between the frequency of headaches and the recurrence of the seasons. In this regard, headaches resemble other functional diseases, including mood disorders, anxiety, unpleasant gastrointestinal illnesses, and sleep disorders, among others. Circadian disruption is a significant contributor to headache recurrence. Irregular sleep-wake patterns, night shift work, and jet lag can lead to a state of circadian misalignment, where the body's internal clock is out of sync with external time cues.

This thematic series aims to investigate the neurological, genetic, and hormonal foundations, along with the clinical and morpho-functional correlations, of the association between chronobiological rhythms and the rhythmic occurrence of primary and secondary headache attacks. This is also considering the cyclical manifestation of other systemic and central illnesses that are significantly associated with headaches. Nonetheless, it will be intriguing to investigate novel behavioural strategies, potentially transdisciplinary, and pharmaceutical methods aimed at addressing these chronobiological factors. The exploration of how circadian entrainment and resetting can alleviate headache burden presents an important new frontier in treatment.

This Collection supports and amplifies research related to SDG 3, Good Health and Well-Being.

All submissions in this collection undergo the journal’s standard peer review process. Similarly, all manuscripts authored by a Guest Editor(s) will be handled by the Editor-in-Chief. As an open access publication, this journal levies an article processing fee (details here). We recognize that many key stakeholders may not have access to such resources and are committed to supporting participation in this issue wherever resources are a barrier. For more information about what support may be available, please visit OA funding and support, or email OAfundingpolicy@springernature.com or the Editor-in-Chief.