BackgroundThere is an ongoing need for effective and accessible preventive interventions for adolescent depression and substance abuse. This paper reports on a field trial of an online indicated preventive intervention, ProjectTECH, which is based on cognitive-behavioral therapy (CBT) techniques. The study aims to gather information about the feasibility and acceptability of this program. Secondary aims of this study were to examine the impact of the program on depression symptoms, perceived stress, positive affect, and substance use and to compare differences between groups that were led by a peer versus those that were led by a licensed clinician.MethodsHigh school students (n = 39) were recruited primarily through social media advertisements, and assigned to four groups of 8–12 individuals to collaboratively participate in an 8 week peer network-based online preventive intervention which were led by a trained peer guide or a licensed clinician. Participants were provided with didactic lessons, CBT-based mood management tools, and peer networking features, and completed quantitative and qualitative feedback at baseline, midpoint, end of intervention, and 1 month follow-up.ResultsThe program attracted and retained users primarily from social media and was used frequently by many of the participants (system login M = 25.62, SD = 16.58). Participants rated the program as usable, and offered several suggestions for improving the program, including allowing for further personalization by the individual user, and including more prompts to engage with the social network. From baseline to end of intervention, significant decreases were observed in depressive symptoms and perceived stress (p's < 0.05). Significant increases in positive affect were observed from baseline to midpoint (p < 0.05) and no changes were observed in substance use, although the rate of substance use was low in this sample. While this study had low power to detect group differences, no consistent differences were observed between participants in a peer-led group and those in a clinician-led group.ConclusionsResults of this study indicate that ProjectTECH, an indicated preventive intervention for high school-aged adolescents, demonstrates both feasibility, acceptability, and short-term, longitudinal psychological benefits for participants. Future iterations of the program may benefit from close attention to user interface design and the continued use of trained peer support guides.