Flash technique enhances subjective and objective cognitive flexibility in college students with childhood trauma: a randomized controlled trial

Childhood trauma is closely associated with decreased cognitive flexibility in college students. To explore a safer and more effective cognitive intervention approach for this population, this study aims to determine the effects of flash technique (FT) on improving subjective and objective cognitive flexibility among college students with childhood trauma.

A randomized controlled study design was adopted. From April to October 2025, Childhood Trauma Questionnaire (CTQ) and semi-structured interviews were used to assess the levels of childhood trauma among college students in some universities in Changqing and Kunming. A total of 54 eligible participants were randomly assigned into an intervention group (n=27) and a waitlist group (n=27). The intervention group received 70-minute FT intervention, once per week for 6 weeks, while the waitlist group received no intervention during the same period. At baseline (T1) and post-intervention (T2), subjective cognitive flexibility was assessed using the Cognitive Flexibility Inventory (CFI). In the letter-number switching task, objective switching efficiency was measured by switching time cost, and switching accuracy was determined by switching error rate cost.

All 54 participants completed the study (27 in each group). ① No significant differences were observed between the 2 groups in demographic characteristics, CTQ, CFI, switching time cost, or switching error rate cost at baseline (P>0. 05). ② Repeated measures analysis of variance revealed significant group-by-time interactions for CFI (F=24. 654, P<0. 001, partial η² =0. 322) and switching time cost (F=6. 603, P=0. 013, partial η² =0. 113), whereas the group-by-time interaction for switching error rate cost was not significant (F=1. 397, P=0. 243, Partial η² =0. 02). ③ Simple effect analysis demonstrated that post-intervention CFI was significantly higher in the intervention group than in the waitlist group (t=3. 054, P=0. 004, 95%CI: 3. 022 to 14. 608), with switching time cost significantly lower (t=-3. 117, P=0. 003, 95%CI: -93. 438 to -20. 251). At T2, the intervention group showed significantly higher CFI (t=7. 424, P<0. 001, 95%CI: 9. 999 to 17. 408) and significantly lower switching time cost (t=-2. 875, P=0. 006, 95%CI: -60. 582 to -10. 780) compared with T1. No significant differences were observed CFI or switching time cost between T1 and T2 in the waitlist group (P>0. 05).

FT can effectively improve subjective cognitive flexibility and objective cognitive switching efficiency in college students with childhood trauma, serving as an effective auxiliary psychological intervention for this population.