Reducing the burden of <scp>PTSD</scp> through digital interventions and development of sequential precision treatment rules
Authors: Corina Benjet
Journal: World Psychiatry (2025)

Brewin et al1 provide a comprehensive, thoughtful and up-to-date review of the conceptualization, diagnosis, prevention and treatment of post-traumatic stress disorder (PTSD). Despite the controversies that surround the evolving definitions of traumatic events and criteria for PTSD, there is no doubt about the societal burden and deleterious impact on population health of post-traumatic psychological distress2. Given the reportedly high prevalence of PTSD1 and the widespread occurrence of trauma exposure – an estimated 70% of the global population has experienced any traumatic event and 30% has been exposed to four or more3 – there are not enough human and financial resources across the globe to realistically treat all those with PTSD, let alone the whole continuum of post-traumatic psychological distress. Furthermore, the majority of those who meet criteria for PTSD never seek treatment, given the stigma associated with mental health in general and some traumas in particular (i.e., rape), and a variety of barriers, both logistical (e.g., time, location) and attitudinal (e.g., beliefs about psychological or pharmacological treatments)2. Therefore, to really impact the global burden of PTSD, we not only need novel interventions, but mostly novel modalities of delivering interventions, that are scalable, accessible and acceptable to the target population. Internet and mobile-based interventions reduce many barriers. They are scalable, since – once developed – they require fewer specialized human resources: there are self-directed versions that require no human resources, and supported versions that require less specialized human resources and/or less time per client than traditional in-person modalities. Digital modalities can increase accessibility because generally they can be used at any time in any place where the user has Internet access. Even in low- or middle-income countries, the population often has greater access to Internet (through mobile phones) than to mental health treatment centers. Finally, digital modalities may reduce barriers related to stigma, as they are often anonymous and match the often-cited reason for not seeking help, the individual wanting to deal with the problem on his/her own2, thus increasing empowerment of self-care. While the literature on the effectiveness of Internet and mobile-based interventions for PTSD is growing and promising, for differing levels of support4, 5, this is only one small step on the road to substantially reduce the global burden of this disorder. There is a great deal of heterogeneity of treatment response even to well-established treatment options. And certainly, digital intervention modalities do not work for all, due to differences in digital literacy, Internet access, motivation, and other yet-to-be determined factors. Therefore, a further step to reducing the burden of PTSD is ideally to use pragmatic precision-treatment modelling to create individualized treatment allocation rules to predict in individual patients which treatment modality will work best, and, given equal probability of success, to provide the optimal treatment at the lowest cost or resource intensity. To my knowledge, no precision treatment rules of this nature have been developed yet for PTSD, but they are emerging for other disorders. For example, in the development of a precision treatment model for university students with depression, we found that 28% were more or equally helped by a self-guided digital cognitive behavioral treatment (CBT) than the guided version of the intervention, and precision treatment rules based on pre-treatment allocation characteristics can predict which treatment is best for whom6. A challenge for the field is that the development of precision treatment rules depends upon large sample sizes, pooling samples from multiple studies with comparable measurements and designs, or trial emulation with large observable samples which are iteratively tested with pragmatic clinical trials7. An even further step along this path to reduce the global burden of PTSD is not only to identify the right treatment for the right person, but the right treatment for the right person at the right time or in the right order. This can be achieved using an iterative staged approach to precision treatment, whereby algorithms are developed to determine the optimal first-line treatment for each individual and, if not successful, which treatment option to offer next and so on. These algorithms can be developed by conducting sequential multiple assignment randomized trials (SMART)8, wherein participants are randomly assigned to a treatment type/modality in the first stage and then, depending on treatment outcome, randomly assigned to further treatments in subsequent stages, resulting in precision treatment based on the individual's pre-treatment characteristics and treatment response. One example is an ongoing SMART for cancer survivors with PTSD symptoms in which participants are randomized in stage 1 to a self-guided app or treatment as usual. Non-responders of both arms are then re-randomized to an increased intensity modality (the app with a clinical guide or a telephone-administered CBT). This approach will therefore provide treatment decision rules based on the four possible sequences9. Such models could also be developed for preventive interventions in trauma-exposed individuals. While guided Internet-based trauma-focused CBT is currently given a lower-strength recommendation by the International Society for Traumatic Stress Studies (ISTSS) and the UK National Institute for Health and Care Excellence (NICE), from a public health perspective a treatment with a smaller effect size but applicable to many more people may go further to reduce PTSD burden globally than a treatment with a larger effect size given to only a few. Brewin et al1 set the stage for future directions. Extending these, a strategic research plan to develop sequential precision treatment rules to determine the optimal first-line modality of preventive intervention and/or treatment (with a range of scalable interventions including digital ones) at the lowest intensity or cost for different people, based on pre-treatment characteristics and initial treatment response, could impact population health and reduce global suffering from PTSD.