This dissertation, "Self-injurious Behaviors in Hong Kong Adolescents: Cross Sectional and Prospective Studies" by Po-shan, Joy, Wong, 黃寶珊, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled Self-injurious behaviors in Hong Kong adolescents: cross sectional and prospective studies submitted by Wong Po Shan, Joy for the degree of Doctor of Philosophy at the University of Hong Kong in February 2006 Background Little is known about self-injurious behaviors (SIB) in non-Western cultures. SIB has become an increasing public health problem. Although early detection of SIB in adolescents could reduce suicide rate in the future, efforts to distinguish SIB from suicide attempts have not been satisfactory. Understanding the differences between the two is important because appropriate prevention/intervention strategies can be implemented at the right timing. 1 Objectives 1. To examine the differences between SIB and suicide attempts in an Asian culture. 2. To study the prevalence of SIB and its trend after 12 months of follow- up. 3. To compare the 3 groups of (A) suicide attempt, (B) SIB and (C) controls at baseline and follow-up. 4. To investigate the predictive factors for SIB and suicide attempt. 5. To explore the roles of different mediators play on SIB and suicide attempt. 6. To investigate subjects' mental health using in-depth diagnostic interview on subjects from the 3 groups above. Study design 1. Baseline cross-sectional study using a structured questionnaire, as a screening tool in students and parents. 2. Prospective study 12 months after the baseline. 3. Assessment using diagnostic interview on selected participants between baseline and follow-up. 2Participants 1,747 students aged 12-18 in the Central and Western District in Hong Kong at baseline in 2003, and data of 1,099 students at T2 who could be matched with those at T1. Results The rates of SIB were 11.4% (95% CI=9.5%-13.3%) at T1 and 8.2% (95% CI=6.6%-10.0%) at T2. Such rates are within the expected range as suggested in the literature. 55.1% of the subjects who engaged in SIB at T1 had suicide attempt at T2. Suicide attempt group had the most psychosocial and behavioral problems (single-parent family, anxiety and depressive symptoms, substance use, life stress, family relationship, parental pathology, suicidal ideation and exposure to suicide attempt), followed by the SIB group, whereas the control group had the least problems (pDepressive symptoms were found as partially mediating between life stress and SIB at T2. Past suicide attempt mediated between suicidal ideation and suicide attempt at both T1 and T2. In addition, SIB was found to be a direct predictor for future suicide attempt. 3 The rate of full diagnosis from in-depth diagnostic interview in the SIB group was about 4 times that of the controls, and the rate of full diagnosis in the suicide attempt group doubled that of the SIB group. Significantly more SIB subjects had the subthresholds of a mood disorder than the controls and suicide attempters, and most suicide attempters had full diagnosis of mood disorders. Conclusions The SIB group was a distinct group who had different predictive factors and mediators from those of the suicide attempters. Although the present study had some limitations, such as the use of self-report method and lack of other important measures, the proposed model may offer a framework for future studies. The use of diagnostic interview and subthresholds have broadened th