INTRODUCTION: Studies suggest that experiences of patient participation, as described by both patients and staff, are associated with a significant caring relationship of high quality. AIM: This study aimed to investigate staffs' and patients' self-reported perceptions on participation and the frequency and importance of verbal and social interactions in high-security forensic psychiatry. METHOD: The questionnaire Verbal and Social Interactions (VSI) was used together with the subscale Participation from Quality in Psychiatric Care (QPC). The study was conducted at a large forensic psychiatric clinic in Sweden. RESULTS: Staff and patients rated the frequency of VSI differently while reporting the same perceived degree of patient participation. All categories of VSI were significantly correlated with perceived level of participation with medium or small effect size for the patients. DISCUSSION: Patients' perceived participation seems to depend on verbal and social interaction within the specific categories 'Showing interest in the patients' feelings, experiences, and behavior' and 'Helping the patients establish structure and routines in their everyday life'. There was, however, a negative association for the latter. IMPLICATIONS FOR PRACTICE: The results give a better understanding of what kind of interactions that affect patients' perceived level of participation. RELEVANCE STATEMENT: Patient participant is a prioritised area for development in forensic psychiatry. The study contributes to a better understanding of what types of interactions that affect the perceived level of participation, while at the same time, it shows important similarities and differences between patient and staff perspectives.