“…Twenty‐eight studies, with a total of 15 792 280 tweets, reported the results of sentiment and thematic analyses on Twitter. Of these studies, 12 assessed e‐cigarette‐related content [24, 26– 28, 33, 34, 36, 37, 39, 43, 48, 53], nine assessed cannabis‐related content [22, 23, 38, 41, 42, 46, 47, 50, 51], five assessed opiate‐related content [20, 21, 25, 40, 56], five assessed tobacco‐related content [32, 35, 44, 45, 52], one assessed alcohol‐related content [30], and a single study assessed polysubstance use‐related content [29].…”