Overview of the Tripod trial


Adolescence can be a difficult time for many young people. Amongst the many pressures experienced by teens, final exams are considered to be among the most stressful. We know that stress can trigger underlying vulnerabilities that can result in mental illness such as depression. Indeed, more than 40% of Year 12 students report symptoms of depression, anxiety and stress that fall outside what is considered the normal range for this age group. 

This Trial for the Prevention of Depression (TriPoD) investigates the effectiveness of a universal prevention intervention for Major Depression Disorder (MDD) in adolescence prior to a major stressor. 

Prevention is estimated to reduce the incidence of depression by as much as 22%, and as such represents an important pathway to explore. Research demonstrates that prevention strategies may help young people avoid or delay developing mental health problems, or help them to recover more quickly when faced with stressful situations. In particular, there is evidence to suggest that universal interventions based on principles of cognitive behavioural therapy (CBT) can be helpful.  Further, e-health developments can be used to overcome practical difficulties of delivering an intervention en masse. Automated online programs with established efficacy can be used to deliver with fidelity without the need for face to face health professional input. Because the prevention effort is aimed at all students (i.e. is universal), engagement is maximised when delivered through the classroom.

As such, using Randomised Controlled Trial (RCT) methodology, TriPoD is investigating the effectiveness of a universal prevention intervention for depression in adolescents prior to the Higher School Certificate (HSC). The trial is currently underway and students in 30 schools across New South Wales (NSW) will be randomly allocated to receive an online, automated, preventative Cognitive Behavioural Therapy (CBT) program or an online control program focused on health and wellbeing.

Meet the researcher

Dr Yael Perry

Interactive technology used in this trial

Automated and controlled online programs


Depression has high disease burden that will not be reduced by treatment alone

By 2030 depression is expected to be the second largest cause of disease burden worldwide. Only 13% of the disease burden of depression can be averted by current treatments, and that, even with improved coverage, clinician competence and adherence, only 36% of depression could be averted using our current knowledge and therapies (Andrews et al., 2004).

Current treatments


Improved coverage, clinical competance and adherence


Unaddressed burden


Prevention reduction


This leaves 64% of the burden of major depression unaddressed. Prevention is estimated to reduce the incidence of depression by 22% and thus represents an under-investigated but critical second pathway to lowering depression rates.

Depression can be prevented using CBT in adolescence

Evidence suggests that CBT is the most reliable method to prevent depression both in adolescence and adulthood.

Seven high quality prevention studies in adolescents indicate moderately strong support for the use of cognitive behaviour therapy (see, for example: Clarke et al., 1995; Garber et al., 2009; Gillham et al., 2006; Martinović et al., 2006; Stice et al., 2008), although interpersonal psychotherapy (see Young et al., 2006), and mixed psychosocial approaches (see E. Ö. Arnarson & Craighead, 2009) have also reported positive findings. Most convincing for adolescents, a recently published study in the BMJ (Merry et al., 2012), found CBT gaming applications were non-inferior to treatment as usual.

Optimal prevention programs


While depression begins to increase at 12-13 years, the growth in the incidence of depression is continuous–almost exponential–with depression emerging at a similar/increasing rate across the adolescent window with no pubertal spike. However, CBT as the intervention requires the cognitive maturity to understand key psychological constructs, suggesting the intervention might be maximal in mid to late adolescence.

Stressor exposure

The stress-diathesis model is most common conceptualisation for the development of depression. The role of stressful life events is readily acknowledged as a predictor and a candidate causal factor in the development of depression (Kendler et al., 2005). Stressful life events precede episodes of depression. Triggers are reported in association with suicide attempts (Wasserman et al., 2012), anxiety and bipolar disorder (Johnson, 2005). Exposing individuals to prevention regardless of risk profile: Research evidence indicates that universal interventions (interventions directed at the full population) are effective for youth depression (see Merry et al., 2004). A universal population based approach as it includes those who go on to develop symptoms, where an indicated intervention may, from a scientific perspective, fail to reveal the full spectrum of responses at the population level.

Adolescent stressors

A significant stressor for adolescents is final examinations at the end of school as indicated by evidence that (a) more than 40% of Year 12 students report symptoms of depression, anxiety and stress that fall outside normal ranges (Smith & Sinclair, 2000); (b) examinations are reported stressors, linked in extreme cases to suicide (Denscombe, 2000) (c) increased examination stress is associated with altered cortisol secretion (Weekes et al., 2006; Weik & Deinzer, 2010); and (d) final year exams are perceived to be major stressors for both young people and their parents. Evidence that prevention may inoculate or produce quicker “bounce back” at the time of stressors: In adolescence, no studies to date have investigated the role of prevention interventions in “inoculating” individuals prior to a major stressor (that is to prevent stress reactions or to diminish/shorten reactions if they do occur). However, one trial has examined this effect in young adults. Our USA collaborators offered MoodGYM, an online CBT-based intervention, to medical students prior to their first year internship. While depression scores, measured by the CES-D (Radloff, 1977) increased over the first three months of hospital work for both control and experimental groups, those exposed to the prevention intervention were less depressed at 3 and 12 months. The intervention completer analyses at 12 months indicated that subjects in the intervention group demonstrated a 62.6% reduction in the incidence of depression and were 3.56 times less likely to develop an episode of depression compared to subjects in the control group (13.0% (3/23) vs. 34.8% (16/46), OR=3.9, p=.049). From an engagement and delivery perspective, e-health developments can be used to overcome the practical difficulties of previous research. Automated online programs with established efficacy can be used to deliver with fidelity without the need for face to face health professional input, facilitated by online/telephone diagnosis tools (Sheehan et al., 1998). Because the prevention effort is aimed at all students (universal), engagement is maximised through classroom delivery. Taken together, the evidence above suggests that optimal prevention in adolescence may take the form of universal prevention targeting depression (but also measuring other disorders), using CBT, undertaken in the mid to late adolescence age range, in anticipation of a major universal stressor (such as a final examination), and measuring a range of vulnerability factors.


800 to 1,600 HSC school students in 30 NSW high schools will be allocated to receive either an online, automated, evidence-based, preventative CBT program or an online control program focused on health and wellbeing.

Students will participate in the intervention in February of Year 12, and will complete assessment measures pre- and post-intervention, approximately 6 months later (prior to the Trial HSC) and at 18-month follow-up.


The primary aim is to determine whether CBT prevention inoculates young people from MDD prior to undertaking the NSW Higher School Certificate (HSC). A secondary aim is to improve academic performance in the examination.

The innovations in this project are that that it is the first prevention trial mounted in anticipation of a major universal stressor, is informed by stress-diathesis theory, and will provide unique knowledge of the mechanisms that lead to MDD, and the predictors of resilience and non-response.


Helen Christensen
Alison Calear
Andrew mackinnon
Philip Batterham
Julio Licinio
Jan Scott
Nick Martin
Tara Donker
Yael Perry


NHMRC Project Grant APP1061072