“…A qualitative approach was employed by more than half of the studies ( n = 20, 54%) [50, 52, 53, 55, 57, 58, 60, 61, 64, 66, 67, 69–71, 76, 77, 79, 82, 83, 85] with n > 1372 participants overall (see Table 1). Of those studies, the majority (60%) focussed on motives related to a specific substance while 40% asked for use motives across different types of SPs.…”