also to an underestimation of prevalence due to absent pupils [4]. However, the increase in prevalence may also reflect a genuine rise in self-harm rates over time as the data were collected approximately eight years apart. There is some evidence that self-harm rates among teenagers and young adults have increased over recent decades so this rise may have continued [3,29]. Further, increases in psychological distress among teenagers in the UK – strongly associated with self-harm in this and other research [5] - have also been reported in some studies [30], although not in others [31].
