2.5.1. RAND-36

General health and HRQoL was assessed by using the Dutch version of the Research and Development-36 (RAND-36) (63), which is the equivalent of the 36-Item Short Form Health Survey with the addition of one extra subscale, i.e., ‘health change’. The Dutch version of the RAND-36 consists of 36 items distributed across nine domains of which subscale scores can be calculated, i.e., physical functioning, role limitations due to physical health problems, role limitations due to emotional problems, general mental health, social functioning, bodily pain, vitality, general health perception and health change. Each domain is scored from 0 to 100, with higher scores indicating better health. In addition, the Physical Component Score (PCS) and Mental Component Score (MCS) can be calculated by using recommended scoring algorithms (64), with scores also ranging from 0 to 100. The PCS primarily reflects physical aspects of HRQoL and the following subscales contribute most to scoring of the PCS: physical functioning, bodily pain and role limitations due to physical health problems. The MCS primarily reflects mental aspects of HRQoL and the following subscales contribute most to scoring of the MCS: general mental health, role limitations due to emotional problems and social functioning (64). Good reliability has been reported with internal coefficients ranging from 0.71–0.93 (65). Several studies also support the validity of the RAND-36 by reporting adequate convergent validity and discriminant validity (65–67). The RAND-36 has been widely used to measure HRQoL in different patient groups, including in patients suffering from mental disorders (68, 69). PCS, MCS and RAND-36 subscales, were used as primary outcome measures in the current study.