目標：本三年追蹤研究旨在探討高職學生開始使用成癮物質(吸菸、飲酒、嚼檳榔、使用成癮藥物)的情況，及其危險與保護因子長期的變化情形。方法：從高一至高三計有1763名台北縣市高職學生完成三年追蹤調查(2000-2002)問卷填答，以邏輯迴歸檢視開始使用成癮物質之危險與保護因子的變化情形。結果：由高一未使用成癮物質者追蹤至高三時分別有166名(11.0%)、184名(13.1%)、40名(2.3%)、28名(1.6%)學生表示開始吸菸、飲酒、嚼檳榔與使用成癮藥物。開始使用成癮物質者較未使用者在高一時顯著有較多的危險因子(如同儕使用、邀約使用、涉足不良場所、使用其他成癮物質如菸、酒等)，且危險因子在高一至高三間增加幅度較大。相對的，開始使用者在高一時的保護因子(如拒絕成癮物質自我效能、反對使用的態度等)顯著較少，且保護因子由高一至高三減少幅度也較大。結論：高一時有較多的危險因子與較少的保護因子及長期變化危險因子的增加與保護因子的減少皆顯著預測高職生開始使用成癮物質的行為。

　　　　　Objectives: This three-year longitudinal study examined changes in the patterns of risk and protective factors of substance initiation (smoking, alcohol use, betel quid chewing, and illicit drug use) among a vocational high school student cohort in Taipei. Methods: A total of 1763 10th graders were followed to the 12th grade (2000-2002). Logistic regression was used to examine the baseline and longitudinal changes in risk and protective factors for substance initiation. Results: Among students who did not use any substances in grade 10, 166 (11.0%), 184 (13.1%), 40 (2.3%), and 28 (1.6%) students initiated smoking, alcohol use, betel quid chewing, and illicit drug use by grade 12, respectively. In the 10th grade, higher risk factors, such as peer use, being offered the substance by another person, concomitant substance use (i.e., smoking and alcohol use), and lower protective factors, such as refusal selp-efficacy and presence of an anti-substance use attitude, predicted youth substance initiation by grade 12. Increases in risk factors and decreases in protective factors from the 10th to 12th grades were significantly associated with substance use initiation in youths. Conclusions: The risk and protective factors in grade 10 and longitudinal changes from grade 10 to 12 predicted youth substance use initiation.