Background: Sibling relationships are very significant relationships, and their termination due to death will have profound long-term effects on the life of the surviving children. Objectives: The purpose of the current study was to determine the effectiveness of theraplay on internalizing and externalizing problems in bereaved siblings. Methods: This study was carried out using a single-subject multiple baseline design with follow-up. The statistical population included siblings and mothers of children aged 6 - 10 years who were on treatment at Mahak Pediatric Cancer Hospital and died one or two years ago. From this population, four mother-child pairs were selected as the study sample by convenience sampling. Each mother-child pair participated in 15 theraplay sessions once a week (45-min sessions). The assessments were carried out using the Child Behavior Checklist (CBCL) at baseline and in the intervention sessions and follow-up. Visual analysis of graphic displays of level, Reliable Change Index (RCI), and clinical significance were used to analyze the data. Data analysis and drawing the graphs were performed in Microsoft Excel 2016. Results: The results of the visual and quantitative data analysis showed a significant reduction in the four participants' internalizing problems during therapy. The reduction in the scores of this subscale in participants 1, 2, and 3 continued into the follow-up period and was noticeable. The results also showed that theraplay reduced the externalizing problems of most participants. A large proportion of these results persisted into the follow-up period. Conclusions: Theraplay appears to effectively reduce the internalizing and externalizing problems of bereaved siblings.

Background: Death of any of siblings is an overwhelming, severe, and prolonged challenge in children development process and is a major risk factor for psychiatric disorders in childhood and later. Interventions for bereaved families following a child’s death have been examined over the last several decades. However, no effective treatment for bereavement siblings prolonged grief disorder (PGD) and post-traumatic stress disorder (PTSD) has been found yet. Objectives: The study aimed at determining the effect of Theraplay on the symptoms of prolonged grief (PG) and post-traumatic stress disorder (PTSD) in siblings of a deceased child with cancer. Methods: In this preliminary study, a multiple baseline single-subject design with a follow-up period was used. The statistical population included siblings and mothers of children aged 6-10 years who had been under treatment at Mahak Child Cancer Hospital and died 1or 2 years ago. From this population, 4 mother-child pairs were selected as the study sample by convenience sampling. Each mother-child pair participated in 15 Theraplay sessions once a week (45-minute section). Assessments were performed using the inventory of prolonged grief for children (IPG-C) and the University of California at Los Angeles Posttraumatic Stress disorder reaction index for DSM-5 (UCLA PTSD-RI) at baseline, intervention sessions and follow-up stages. Visual analysis of graphic displays of level, reliable change index (RCI) and clinical significance were used to analyze the data. Data analysis and drawing graphs were performed in Microsoft Excel 2016. Results: Results of visual and quantitative analysis of data showed that PG symptoms decreased in all 4 participants during the treatment and follow-up. Also, according to the results, Theraplay intervention significantly reduced PTSD in all participants. Conclusions: Theraplay appears to be effective in reducing PG and PTSD in bereaved siblings. However, the reduction rate varied in different subjects. According to the findings, Theraplay helped subjects accept grief and loss and this method can be used to help the mental health of other bereaved children.