The prevalence of mental health disorders, particularly depression, is very high in adolescence with 10% of teenagers experiencing a major depressive episode every year.  The impact of mental health disease on well-being in this critical developmental stage is quite obvious with impairment in social and educational activities, but also often results in serious physical health problems and self-harm. Even when treatment is available, many young sufferers fail to recover and go on to develop serious mental health conditions in adult life.
With the advent of technology and with most adolescents being heavy users of the internet, there have been a number of online tools designed to provide accessible and high-quality psychological therapy which has proven to be just as effective as person-to-person therapies.  Whilst the success of such methods is evident, questions have been recently raised as to how to further improve and harness the efficacy of e-mental health methods. Instead of waiting for depressive symptoms to develop and then trying to actively treat, why not take a step back and try preventing depression from occurring in the first place? Prevention of disease is a major theme in public health in a variety of organic diseases and we believe there is plenty of scope for it in mental health as well.
The following study presents a case where 84 adolescents thought to be vulnerable to developing depression were enrolled in a trial largely comprising of an internet-based programme accompanied by either brief advice (1-2 minutes) or a short motivational interview (5-15 minutes) from their primary care provider.  Following this prevention programme, there was a significant increase in protective factors and a decrease in vulnerability factors (individual, family, school and peer factors) in both groups.
The participants engaged heavily with the internet-based prevention therapy which was deemed to be the main factor contributing to the improvement. In designing the online tool, the instructional design theory was employed in order to actively engage adolescents in reducing vulnerability and enhancing protective factors. 
The success of this particular type of design is probably due to its structure which aims to:
1. gain attention of the learner
2. inform the learner of objectives
3. strengthen recall of essential knowledge
4. provide needed stimulus material
5. offer learning guidance
6. measure performance
7. offer feedback on performance correctness
8. evaluate performance
9. increase transfer and retention
The results from this study show the potential benefits of prevention methods for depression using a dual approach consisting of primary care counselling, but mostly of internet-based psycho-education. Clinicians and teachers could potentially consider engaging adolescents in such self-education and prevention methods employing instructional design theory, leading to a positive impact on mental health.
 Kessler RC, Walters EE. Epidemiology of DSM-III-R major depression and minor depression among adolescents and young adults in the National Comorbidity Survey. Depression & Anxiety. 1998;7(1):3–14. [PubMed]
 Spek et al. Internet-based cognitive behaviour therapy for symptoms of depression and anxiety: a meta-analysis.
 Voohees et al. Integrative Internet-Based Depression Prevention for Adolescents: A Randomized Clinical Trial in Primary Care for Vulnerability and Protective Factors
 Briggs LJ, Briggs RM, Gagne LJ, Wager WW. Principles of Instructional Design. Fort Worth, TX: Harcourt Brace Jovanovich College Publishers; 1992.
Mihai Bica is a 5th year medical student at the University of Cambridge and is particularly interested in mental health and ophthalmology.
Caitlin Walker is a BSc student of Biological Natural Sciences at the University of Cambridge and is particularly interested in the causes of mental health disorders and how these can be addressed through prevention methods.
Zsófia Szlamka is an M.Phil student in Social and Developmental Psychology at the University of Cambridge. Her research focuses on autism spectrum disorder and she has a developing interest in policy research.
Theo St John Steven is a student in History at the University of Cambridge.
Mei Yin Wong is a medical student at the University of Cambridge.