2 - (OP25) Dropout Rate and Related Factors in Group Psychotherapy: A Retrospective Study

Objective
Group psychotherapy (hereafter, group) has been widely applied in the intervention for mental health disorders. However, patient dropout is an obstacle limiting therapeutic effectiveness. This study aims to investigate patient dropout and the factors contributing to dropout rates in outpatient groups.
Method
This study included 620 patients who participated in group at outpatient clinics of a psychiatric hospital between July 2023 and June 2025. Only groups grounded in cognitive behavioral therapy (CBT) or related techniques were included. Groups with fewer than three cohorts or those based on non-CBT therapeutic orientations were excluded.
The final sample comprised 538 patients (86.77%) with ages ranging from 12 to 67 years. The distribution of group themes was as follows: CBT (n = 27), exposure and response prevention (ERP; n = 26), mindfulness-based cognitive therapy (MBCT; n = 149), dialectical behavior therapy (DBT; n = 314), and CBT-based school adaptation group (n = 22). After excluding DBT parent groups delivered on a family basis, the sample consisted of 133 male and 293 female participants.
Patient-, participation-, and therapist-related variables were retrospectively collected and analyzed. Group differences in dropout were examined, and correlation analyses were conducted to assess associations between therapist experience and dropout.
Result
Overall dropout rate for groups was 26%, ranging from 9.09%~28.66% across groups with no statistically significant differences (χ²=6, p=0.20). Dropout rates differed by patient gender, with a higher rate among females (30.0%) than among males (20.3%). Subgroup analyses among patients who dropped out revealed significant gender differences across group themes (χ²=11, p=0.03), with a higher proportion of males (60%) than females (40%) in the CBT and ERP groups. No significant differences were found with respect to patient age, concurrent or previous engagement in other forms of psychotherapy.
Patients entered group an average of 27 days after initial interview, and the waiting time showed no significant association with dropout. The calendar quarter in which the group initiated was significantly associated with dropout (χ²=13, p=0.006), with the lowest rate of dropout observed in the third quarter (17.9%) and the highest in the fourth (34.3%).
Therapists’ individual therapy experience showed a significant negative correlation with subsequent group dropout among patients they initially interviewed (r=-0.71, p=0.03). Group-leading experience was also negatively correlated with dropout rates for which the therapist served as the group leader (r=-0.66, p=0.04). However, no significant differences were found in co-therapists.
Conclusion
Female patients show a higher dropout rate compared to males, specifically those in MBCT groups. The form of camps is associated with a lower dropout rate in DBT adolescent groups, suggesting that short-term, intense DBT protocol may help improve adherence in teenagers. The third quarter of the year appeared to be an optimal period for starting a group, as dropout rates were lowest during this time. Greater clinical experience of therapists was associated with lower dropout from group, suggesting the needs for enhanced training.