ABSTRACT Objective This study aims to investigate the effectiveness of emotion regulation training (ERT) based on Gross's process model combined with medication therapy on mania severity, depression, and emotion regulation of adults with bipolar disorder (BD) type 1. Methods This is a randomized, controlled clinical trial on 37 adults (26 females and 11 males) with BD type 1 (depressive phase) assigned to two parallel groups of medication + ERT ( n = 19) and medication ( n = 18). Their mania, depression, and emotion regulation were measured by the Young mania rating scale (YMRS), the Hamilton depression rating scale (HDRS), and the emotion regulation questionnaire (ERQ) before, immediately after and 3 months after the intervention. The medication therapy included the uptake of mood stabilizers (2–5 tablets of lithium 300 mg, sodium valproate 200 mg and carbamazepine 200 mg) two times per day. The ERT was provided 2 months after receiving mood stabilizers at 8 sessions for 4 weeks, according to Gross's model. After collecting data, they were analysed in SPSS v.26 software. Results The difference between the two groups was statistically significant over time in the YMRS ( p < 0.001, η 2 = 0.42) and HDRS ( p = 0.007, η 2 = 0.19) scores, where more significant reductions were reported in the medication + ERT group and maintained for 3 months. Regarding the ERQ score, a significant difference between groups was observed only in the cognitive reappraisal domain ( p < 0.001, η 2 = 0.302) and in the total score ( p = 0.001, η 2 = 0.227) over time, where significant improvements were reported in the medication + ERT group and maintained for 3 months. Conclusion The augmentation of medication therapy with the Gross model‐based ERT can lead to a higher decrease in mania and depression and an increase in emotion regulation (cognitive reappraisal) of depressed adults with BD type 1.
