To develop and pilot test feasibility, acceptability, and efficacy of an adjunct intervention for use with Empirically Based Treatments (EBT) for posttraumatic stress disorder (PTSD) in order to increase treatment engagement, treatment completion, and improve treatment response regarding emotional numbing symptoms. Recovery through Engagement with Shelter Canines, Understanding, and Exposure (RESCUE), is an adjunctive, Human Animal Interaction (HAI) intervention that will be developed for integration into Prolonged Exposure (PE) treatment. Feasibility, acceptability, and initial efficacy testing of the experimental treatment condition will be conducted in a pilot crossover randomized controlled trial (RCT) conducted with 75 veterans with PTSD randomly assigned to RESCUE delivered with PE (RESCUE+PE) or to standard PE initiation (PE + delayed RESCUE).

Inclusion Criteria:

1. Veterans with a principal Diagnostic and Statistical Manual-5th edition (DSM-5) PTSD diagnosis (via CAPS) stemming from a Criterion A event.
2. Men or women aged 18 to 64 inclusive.
3. Given that individuals with PTSD often have comorbid psychiatric disorders, participants with comorbid depressive, anxiety, substance use disorders, and personality disorders other than Antisocial Personality Disorder will be included as long as PTSD is the primary disorder
4. Individuals with the ability to comprehend and satisfactorily comply with protocol requirements and who sign the written informed consent given prior to entering any study procedure

Exclusion Criteria:

1. Individuals with active substance use disorders that require medical detoxification will be initially excluded from participation, but will be eligible once they have completed their detoxification.
2. Veterans with comorbid Antisocial Personality Disorder, or history of animal cruelty will be excluded. Veterans with comorbid disorders that fall into the following DSM-5 categories will also be excluded: delirium, dementia, amnestic disorders, other cognitive disorders and psychotic disorders. Veterans with active Bipolar I or II and are not on a stable medication regime will be excluded.
3. Given evidence suggesting that benzodiazepine medications restrict the therapeutic benefits of PE, potential participants will be required to taper and cease use under supervision of their prescribing physician. Participants must be off benzodiazepines for at least two weeks prior to enrolling in the study. Patients using antidepressant medication for PTSD will be eligible for participation as long as they are on a stable regimen (i.e., consistent dose for at least two weeks prior to enrollment and throughout the study).
4. For safety purposes, Veterans who based on history or mental status examination have a significant risk of committing suicide, or who are homicidal or violent and who are in the Investigator's opinion in significant imminent risk of hurting others, will be excluded.
5. Patients who are unable to speak, read, and understand English or are judged by the investigator to be unable or unlikely to follow the study protocol and complete all scheduled visits.
6. Patients who report a dog phobia or are otherwise opposed to working with dogs.