| dc.description.abstract | Background: This thesis investigated longitudinal gender differences between heavy episodic drinking and self-harm thoughts in study one, and self-harm behavior in study two. There do exist some research on the longitudinal relationship between adolescent heavy episodic drinking and deliberate self-harm, but it is more than 20 years old. To the best of my knowledge, there has been no previous longitudinal investigation of gender differences in self-harm thoughts and heavy episodic drinking, and neither has there been such an investigation for self-harm behavior and heavy episodic drinking. The research from this thesis is important, as it investigates the association between heavy episodic drinking and self-harm in ways it has not been previously. I assumed that heavy episodic drinking and self-harm would be associated, both within the same time measures and longitudinally. In addition, to assuming that self-harm would precede heavy episodic drinking in girls, and that heavy episodic drinking would precede self-harm in boys. Method: Data used in this thesis were collected for the MyLife study and the MyLife pilot study. Both of them are longitudinal datasets, and the data from the MyLife study was collected with a 12-month gap, while the data from the MyLife pilot were collected with a six-month gap. The participants who participated in the MyLife study or MyLife pilot study were Norwegian students in eighth, ninth and 10th grade at the first time measure. In time measure two and three, they had naturally progressed to a higher grade. With the exception that those who participated in the MyLife pilot study were still in the same grade in time measure two as they were in time measure one. In order to investigate heavy episodic drinking and self-harm thoughts in study one and heavy episodic drinking and self-harm behavior in study two, a cross-lagged panel analysis was conducted in STATA 16, for each study. Study one, which investigated heavy episodic drinking and self-harm thoughts, was based on data from the MyLife study, and had 2,975 participants, 56% girls, and 44% boys. Study two, which investigated heavy episodic drinking and self-harm behavior, was based on data from the MyLife pilot study, and had 447 participants, with 55% girls and 45% boys. Results: This thesis offers support for heavy episodic drinking being partially associated with both self-harm thoughts and self-harm behavior, longitudinally and within the same time measure. However, the assumptions related to gender were not true, as both girls and boys reported heavy episodic drinking before self-harm thoughts and behavior. | eng |