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Background Social jetlag (SJL)—the mismatch between biological timing and socially required schedules—is increasingly recognised as an indicator of circadian strain in young adults. It has been associated with insomnia symptoms, chronotype, fatigue, and daytime sleepiness, with these effects more pronounced in neurodivergent (ND) groups (Coogan & McGowan, 2017; Baker & Richdale, 2017). UK data describing SJL distributions and their sleep-related correlates remain limited in university students and are almost absent for NHS staff.Methods Year-2 undergraduate students (n=58; age 19–34; F/M 35/23) completed the Epworth Sleepiness Scale (ESS), Morning–Evening Questionnaire (MEQ), Multidimensional Fatigue Inventory (MFI-20), Insomnia Severity Index (ISI), and the optional Humour Styles Questionnaire (HSQ). Participants were categorised into four SJL groups: <0.5, 0.5–1.0, 1.0–2.0, and >2.0 hours, with >2.0 hours indicating clinically meaningful misalignment (Wittmann et al., 2006). The sample was subdivided into ND (n=13) and neurotypical (NT; n=45) groups. Analyses were conducted in GraphPad v10.6.1 using unpaired t-tests (ND–NT) and ANOVA (SJL groups). Data are presented as mean(SD).Results Table 1 summarises the findings. Significant group differences were observed only for ESS (p<0.01), with the highest score being 12. Subthreshold insomnia (ISI 8–14) was present in 19% of participants. MEQ classifications showed 19% Evening-type and 17% Morning-type individuals, with the remainder intermediate. MFI-20 data indicated moderate levels of general fatigue (22%), physical fatigue (26%), reduced activity (16%), reduced motivation (20%), and moderate-to-high mental fatigue (52%). Overall, 30% reported elevated global fatigue.Among those completing the HSQ (n=49), 25% showed moderate affiliative humour use, 60% moderate-to-high aggressive humour, 82% moderate-to-high self-enhancing humour, and 94% moderate-to-high self-defeating humour. ND and NT patterns were broadly similar, though numbers were small.Conclusion Despite low ESS and ISI scores, over one-third of participants were classified as Morning or Evening types, which may influence engagement with scheduled teaching. Fatigue was common, particularly mental fatigue. Humour styles varied, with affiliative humour least used and self-defeating humour most prevalent. This pilot dataset provides an initial picture of SJL and its associations with mood, cognitive functioning, and physiological strain. Further work is required to explore these relationships and extend findings to both student and healthcare populations.Abstract P42 Table 1Summary of data divided into social jet lag (SJL) groups. Data are presented as mean (SD)<0.50.5 – 1.01.0 to 2.0>2.0Group (n = 58)19161211ESS4.6 (2.7)7.3 (2.4)4.2 (3.6)7.0 (2.86)ISI7.2 (1.7)7.3 (3.7) 8.7 (2.3)7.7 (2.9)MEQ48.1 (8.8)52.8 (10.2)44.1 (8.8)46.7 (9.7)MFI-20 – General10.7 (2.1)11.3 (1.8)12.2 (1.9)12.2 (1.5)MFI-20 – Physical10.6 (1.4)10.9 (2.0)10.7 (2.3)11.5 (2.6)MFI-20 – Activity9.6 (3.4)9.3 (3.3)10.7 (2.7)10.3 (3.5)MFI-20 – Motivation10 (2.9)9.7 (2.8)10.5 (3.2)9.8 (3.1)MFI-20 – Mental11.7 (3.9)11.3 (3.7)12.7 (4.6)12.3 (2.6)MFI-20 – Total52.6 (11.0)52.4 (8.7)56.7 (11.1)55.2 (10.3)Group (n = 49)HSQ – Affiliate21.9 (7.0)21.9 (7.0)16.1 (1.8)18.6 (4.9)HSQ – Self-Enhancing33.6 (6.8)34.2 (6.5)37.1 (5.5)36.0 (6.5)HSQ – Aggressive26.9 (7.3)26.2 (6.6)31.8 (9.6)26.0 (5.5)HSQ – Self-Defeating32.3 (5.0)32.9 (3.9)31.6 (6.8)33.0 (2.5)<0.50 is normal, 0.5-1.0 is mildly elevate, 1.0-2.0 is moderately raised SJL and > 2.0 is abnormal/high risk. ESS – Epworth Sleepiness Score, ISI – Insomnia Severity Index, MEQ – Morning-Evening questionnaire, MFI-20 – Multidimensional Fatigue Inventory, HSQ – Humour Styles Questionnaire.