The goal of this clinical trial is to learn if a new therapy called Acceptance- and Mindfulness-Based Exposure Therapy (AMBET) helps treat post-traumatic stress disorder (PTSD) in people who survived a cardiac arrest. This study will compare AMBET to another psychotherapy treatment called Present Centered Therapy (PCT) to see which therapy is more effective in treating PTSD.

The main questions it aims to answer are:

Does AMBET reduce PTSD symptoms in survivors of cardiac arrest? How do the benefits of AMBET compare to PCT?

Participants will:

• Be randomly assigned to receive either AMBET or PCT
• Attend 12 hours of individual psychotherapy sessions over about 12 weeks
• Complete short weekly surveys about their mood and behaviors online
• Wear a Fitbit device to track sleep and activity during the study
• Do brief homework assignments between sessions

Inclusion Criteria:

1. Between 18 and 81 years old at the time of consent
2. Fluency in English
3. Medical history of cardiac arrest >3 months ago
4. Clinically elevated PTSD symptoms (Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) score ≥25)
5. U.S. Resident

Exclusion Criteria:

1. Lifetime history of primary psychotic or bipolar disorders
2. Current substance use disorder (moderate or severe in the past 6 months)
3. Active suicidal ideation with some intent to act in past 12 months, and/or suicide attempt in past 24 months
4. Substantial cognitive impairment (Mini Mental Status Exam (MMSE) score <25)
5. Initiation of new psychotropic medication <3 months ago
6. Non-cardiac etiology of CA (drowning, bleeding, trauma, drug overdose, etc)
7. Terminal illness with life expectancy <1 year
8. Concurrent psychotherapy for PTSD