Supplementary Material for: IMPULS: Impulsivity-Focused Group Intervention to Reduce Binge Eating Episodes in Patients with Binge Eating Disorder – A Randomised Controlled Trial

Background: Impulsivity is a risk factor for binge eating disorder, and binge eating (BE) equates to impulsive eating behaviour. Hence, we developed IMPULS, a cognitive behavioural group intervention focusing on impulsive eating. Methods: We randomised 41 patients to the IMPULS group and 39 to the control group. The IMPULS group participated in the IMPULS treatment, while both groups completed weekly self-observations. We compared both groups concerning BE episodes in the past 4 weeks at the end of treatment (primary outcome). As secondary outcomes, we investigated eating pathology, depression, general impulsivity and body mass index (BMI) at the end of treatment and in a 3-month follow-up. Results: The primary outcome failed, because BE episodes in the past 4 weeks were reduced in both groups at the end of treatment. At follow-up, the IMPULS group showed further improvement, contrary to the control group. The BE days/episodes in the 2 months before were overall reduced in both groups. Eating pathology was reduced in the IMPULS group at the end of treatment and partly in both groups at the follow-up. Depression was only reduced in the IMPULS group. General impulsivity and BMI did not change. Conclusions: The IMPULS study has a negative primary outcome. However, secondary outcomes indicate that the IMPULS treatment might be promising, as BE, eating pathology and depression were reduced in the IMPULS group. The initially reduced BE in the control group might represent a short-term effect from the self-observations. General impulsivity and BMI might need a longer time or more intensive treatment to change.