This project is a preliminary randomized controlled trial testing the potential impact of the PTSD Coach mobile application at reducing posttraumatic stress and pain symptoms among acutely injured trauma patients. Immediately following the injury, patients will be randomly assigned to use the PTSD Coach app, or to the treatment as usual condition.

Traumatic injury is the leading cause of mortality in the U.S. for young people, and a source of long-term morbidity in all ages. A majority of trauma patients report chronic pain (CP) and disability at 4-months (30%- 79%) and 12-months (63%) post-injury. Maladaptive psychological processes have a stronger association with the transition to CP than does injury severity. Posttraumatic stress disorder (PTSD) symptoms (e.g., intrusions, avoidance and hyperarousal) occur in up to 22% of post-injury patients and herald the transition from acute to CP. Although psychological interventions can modify PTSD symptoms, and reduce CP, it is unknown if early intervention to prevent PTSD symptoms can prevent post-injury CP altogether. "PTSD Coach" is a publicly available, free, mobile app that provides scalable and psychosocial support modeled on principles of cognitive-behavioral therapy. PTSD Coach has helped Veterans and civilians to manage PTSD.

This project will test whether PTSD Coach can reduce post-injury maladaptive psychological processes and thereby prevent post-injury CP. The preventive intervention will be targeted towards those at the highest-risk of developing PTSD.

The investigators propose to test the efficacy of the PTSD Coach app vs. treatment as usual (TAU) among a sample of acute physical injury patients, to: 1) Determine engagement with PTSD Coach, by measuring frequency of use over 4-weeks and assessing ratings of usefulness and qualitative feedback: it is expected that >80% of PTSD Coach users will use the app at least once a week, and will rate it as at least somewhat helpful; 2) Estimate effect on CP symptoms by measuring PTSD and pain intensity at 1- and 3-months. The effect of the intervention on pain interference, disability, and coping self-efficacy will also be explored.

Inclusion Criteria:

• English-speaking adults seeking treatment in the ED
• Adults between the ages of 18-65
• Sustained a musculoskeletal injury (e.g., fractures, sprains or strains, contusions, dislocations, crushing injuries and open wounds; and other chief complains involving the neck, back, or extremities)
• Injury resulting from a motor vehicle crash (MVC) or motorcycle crash (MCC) that occurred within the past 24 hours
• Eligible patients must own a mobile phone with short-message service (SMS) features (e.g., the ability to send and respond to text messages) and the ability to download apps
• Participants must self-report that they experienced a potential traumatic event reflected by Criterion A of the DSM-5 PTSD diagnosis (endorse actual or perceived life threat and/or serious injury141,142)
• Participants must self-report that they experienced a painful injury reflected by a pain score ≥4 using the verbal numerical score (0-10) in response to the question: "On a scale of 0-10, how severe is your pain?"
• Patients with a past history of PTSD, but not currently receiving treatment (e.g., benzodiazepines or mental/behavioral therapy), are eligible for participation.

Exclusion Criteria:

• Presenting to the ED for a non-MVC/MCC (i.e., fall, assault)
• Participants who do not own a mobile phone with SMS features
• Participants with a pain score < 4 or do not endorse Criterion A of the DSM-5 PTSD diagnosis
• Spinal injuries
• Major lacerations resulting in significant damage to subcutaneous tissue (e.g., degloving) and specific nerve injury (these injuries could lead to a distinct neuropathic pain syndrome)
• Traumatic brain injury; Evidence of moderate to severe cognitive impairment secondary to trauma-related head injury (GCS<13)
• Self-inflicted injury
• Time since trauma > 24 hours
• Non-English speaking; younger than 18 or older than 65
• Not medically stable or alert and oriented
• Initiation of benzodiazepines and other psychotropic medications at time of ED visit
• Initiation of mental or behavioral health therapy at time of ED visit
• Currently enrolled in treatment (medication or mental/behavioral health therapy) for PTSD
• Prisoners

There is no plan in place yet because it is undecided whether the research team will need to share the data with investigators/researchers not listed on the protocol.