Nightmares are a re-experiencing symptom of Post-Traumatic Stress Disorder (PTSD) and Complex PTSD (CPTSD). They are intrusive, involuntary and have a significant impact on wellbeing, suggesting they have substantial clinical relevance. However, little is known about the phenomenological features of post-traumatic nightmares and how they are associated with the severity of PTSD and CPTSD symptoms.

Participants (N = 398) who identified that they had experienced a lifetime trauma completed various self-report questionnaires related to PTSD symptoms, CPTSD symptoms and nightmare characteristics. Participants also described their sensory experiences and rated the emotional intensity and vividness of their post-traumatic nightmares.

We found that elevated scores on various characteristics of nightmares including frequency of awakenings, nightmare severity, impact on wellbeing and the perceived realism of the nightmare were linked to more severe PTSD and CPTSD symptoms. Further, increased frequency, vividness, and emotional intensity of nightmares significantly predicted more severe PTSD symptoms but not CPTSD symptoms.

Our study was largely exploratory and was the first to identify that specific nightmare features are related to PTSD and CPTSD symptom severity. However, although nightmare features of frequency, vividness and intensity appear to be related to CPTSD symptom severity, other variables may better predict CPTSD symptoms. Possible explanations for our findings, implications for treatment and directions for future research are discussed.