Anxiety disorders rank high among the most common mental health disorders worldwide . Anxiety disorders include generalized anxiety disorder (GAD), panic disorder and agoraphobia (PD/A), panic attacks (PA), specific phobia (SP), and social anxiety disorder (SAD) . In general, anxiety is characterized by excessive worry about everyday events, irrespective of whether they are internal or external or originating in the past, present or future . In Europe, 12-month prevalence of anxiety disorders has been estimated at 14% [3–5].
GAD is typically considered a chronic condition; a homogenous disorder characterized by excessive worry affecting several domains including restlessness, fatigue, difficulties concentrating, muscle tension, sleep disturbances, and irritability . In Europe the lifetime prevalence of GAD has been estimated at 4.3 to 5.9%, with a 12-month prevalence of 1.2 to 1.9%, yet only a very small percentage seek treatment . GAD, like other mental health disorders, often presents with comorbidity - principally mood disorders or other types of anxiety disorder [4, 8]. GAD is associated with significant deleterious effects: economic, personal, intrapersonal and societal [9, 10], which can cause significant impairment and reduced quality of life for an individual and their family .
Anxiety and students
Several studies have reported elevated levels of anxiety and stress in university students . The prevalence of anxiety in high school and university students has been reported to be between 25 and 30%, in response to their academic demands [13, 14]. Academic stress is highly prevalent and it can contribute significantly to anxiety and depression among college students. For instance, a recent survey of young adult students in Ireland using the Depression Anxiety Stress Scale (DASS-21) , showed levels of clinical anxiety at 36% (8% in the mild range, 15% in the moderate range, 5% in the severe and a further 9% in the very severe range) and 30% with clinical symptoms of stress (10% in the mild range, 10% in the moderate range and 10% in the severe (7%) to very severe (3%) range) .
The transition to university and the management of the resulting academic demands can be a stressful time for many students. The majority of students are at a developmental stage where the onset of mental health difficulties can arise and any stressors may act as a catalyst for their onset [12, 17, 18]. Indeed, young adults aged between 17 and 25 are at high risk of developing a serious mental illness such as an anxiety disorder, and whilst sometimes mental disorders can be difficult to diagnose early on, the risk of delayed diagnosis is often associated with treatment resistance and poorer longer-term outcomes . The result of a lack of opportunity for early diagnosis and treatment can often mean academic failure and dropping out of university. Furthermore, any such underachievement or failure can have long-term consequences on self-esteem and progress in future life .
Since the publication of the Royal College of Psychiatrists updated report (2011) on the mental health of students at university, there is no evidence of the abating of the concerns that were previously raised  he demand for counseling and mental health services among students has only increased . This is due to a broad range of factors, including the rise of family breakdowns, the increase in student monetary contributions to university, the changing demographic of the student population (with a greater diversity of international students), and the case that many students now have to work to survive, places an increased demand not only on their time but also their mental health and wellbeing .
Treating anxiety disorders
Anxiety can be treated successfully through disorder specific treatment plans or treatments that target common elements and symptoms across anxiety disorders [19, 20]. Treatments for GAD include pharmacological and psychological and both have demonstrated their efficacy . By far the most extensively researched psychological treatment for GAD is cognitive-behavior therapy (CBT) which has been shown to be a highly effective treatment for GAD . Different cognitive and behavioral techniques compose any treatment for GAD. They can include cognitive restructuring, behavioral exposure, worry exposure (staying with feared outcomes), relaxation training, and problem solving, among others. CBT for GAD aims to help the user overcome emotional avoidance and learn that their anxiety is not debilitating, but can be managed and indeed recede over time [23–25].
To date a number of theoretical models have been proposed for GAD . Perhaps the most well-defined and empirically supported of these are the Avoidance Model of Worry and GAD (AMW)  and the Intolerance of Uncertainty Model (IUM) . Both have gathered supporting empirical evidence for their central constructs and have developed and researched treatment protocols based on their model . The IUM is largely a cognitive model explaining the pathogenesis of GAD, whereas the AMW is an integrated model that includes cognitive alongside emotional and behavioral components. The treatment protocol used in this study is largely based on the AMW model of GAD.
It is the case that many with anxiety disorders have no diagnosis nor seek treatment [29, 30]. Consequently, mental health disorders such as anxiety disorders often go undetected, especially where accessing psychological services is difficult and/or services are overburdened, as is the case for many university institutions [12, 31]. Additional barriers to accessing treatment exist, such as a lack of available trained professionals, waiting lists, lack of motivation for change, negative perception of psychological treatments, indirect costs of treatment (and direct costs in some cases), personal difficulty such as stigma, and low mental health literacy. Each of this barriers can play an important role in choosing whether or not to seek diagnosis and treatment [32, 33].
CBT as a brief psychological interventions has demonstrated its efficacy and has the potential to significantly reduce the burden of anxiety disorders . CBT is highly suitable to being delivered as a low-intensity intervention within a model of stepped-care . Ireland is far behind its European neighbors in developing and implementing stepped-care models for mental health service delivery that involve both low-intensity (such as bibliotherapy) and high-intensity (such as face-to-face therapy) interventions, despite it being recommended as best practice  and its demonstrated success to date .
Stepped-care model of treatment
The central idea in developing stepped-care models in mental health is to extend access . In recent years attempts to overcome barriers to access have been addressed through the development and implementation of a wide range of low-intensity interventions including internet-delivered treatment programs. Programs have been developed and employed in the treatment of a range of disorders and their results support their efficacy [39–42]. Internet-delivered treatments for anxiety disorders have included interventions for panic disorder, SAD, SP, and posttraumatic stress and they have established findings that support their potential effectiveness and efficacy [43–47].
More precisely, a number of studies have investigated the potential for internet-delivered treatments for GAD and they have reported significant post-treatment and follow-up gains [33, 48–51] similar to those found in face-to-face treatment studies . A recent meta-analysis of internet-delivered treatments for GAD demonstrated large post-treatment effects for GAD symptoms (d = 0.91) and pathological worry (d = 0.73) in favor of the active interventions when compared to waiting list control groups . In addition, online studies for anxiety treatment that provide human support yield enhanced results when compared to those with no human support . The demand for psychological treatments will never be met from high-intensity therapy, therefore internet-delivered treatments are a valuable alternative.
Delivering online low-intensity interventions for GAD
The internet offers the possibility of delivering a treatment intervention at low cost and perhaps overcoming some of the barriers to access mentioned earlier. Online technologies can deliver treatment incrementally and in an engaging way. Furthermore, internet penetration in Ireland is at 76.8%  and it is likely that it is an attractive medium, especially for younger people as they are already high users of the internet and related tools. In a recent Irish survey that asked a student sample about the places they were likely to use as a source of support, the internet was the highest scoring answer at 78%, above friends, parents, doctors, or other professionals .
Some previous research has assessed the relevance of low-intensity internet-delivered treatments for anxiety disorders in service-based settings [56–58]. However, only a handful of studies have investigated the efficacy and effectiveness of low-intensity internet-delivered treatments for GAD [33, 48–51]. The current study seeks to make a contribution towards understanding the relevance of a low-intensity internet-delivered treatment for GAD in a service-based setting in Ireland.
Therefore, using established CBT principles informing skills and strategies for the management of GAD in an integrated disorder-specific treatment plan, the study aims to deploy these using a novel digital health software platform (SilverCloud SilverCloudHealth Ltd., The Priory, John’s Street West, Dublin 8, Ireland.) that integrates a number of innovative engagement strategies for improving the user experience: personal, interactive, supportive, and social . The details of the platform and the content of treatment are described in more detail below.
Dropout from online treatments
A problem that has faced online treatments in general, and more particularly self-administered treatments without support, is that of dropout . Dropout is a continued cause of concern as it is suggested that completing the entire course will benefit users, although several online studies have reported benefits for users who have not completed the entire course of treatment . Some studies have collected information regarding dropout, suggesting difficulties using the computer, negative features of the program, perceiving the course as too demanding, poor clinical progress, receiving alternative treatment, feeling better, lack of time, and problems understanding the computer program [42, 62]. The technology used in the current study has been specifically designed to include a number of engagement strategies for improving the user experience: personal, interactive, supportive, and social. An investigation of dropout will be valuable in assessing the user’s experience of online delivery.
Objectives of the trial
The study aims to implement and evaluate the effectiveness of a low-intensity online self-administered treatment for anxiety (with support) for students with GAD symptoms. There are four research questions. Firstly, can an online treatment for GAD symptoms be effective for an adult student population in a service-based setting? Secondly, what do participants find helpful and hindering in their online treatment for GAD symptoms? Thirdly, are participants satisfied with accessing and using an online treatment? Fourth and finally, what are the reasons for dropout from an online treatment?
Based on the success that has been achieved with supported online treatments in general [42, 54, 63, 64] and with internet-delivered interventions for GAD [33, 48–51, 65], we hypothesize that participants in the trial will demonstrate significant decreases in GAD symptoms post-intervention and a corresponding positive change in pathological worry and quality of life.