Posttraumatic stress disorder (PTSD) is highly prevalent within prison settings, yet is often unidentified and undertreated. Complex PTSD (CPTSD) has been recently formally recognised in the International Classification of Diseases 11th revision (ICD-11) diagnostic framework but has never been explored in prison settings. We aimed to establish the prevalence of ICD-11 PTSD and CPTSD in a UK prison sample using a validated instrument (the International Trauma Questionnaire). We also explored the associations of these two diagnoses with their traumatic antecedents and psychiatric comorbidities.

Randomly selected male, sentenced prisoners in a large medium-security prison in south London (N = 221) took part in a clinical interview which assessed PTSD, CPTSD, trauma histories, and comorbid disorders. Multinomial logistic regression was performed to examine differences between those with PTSD or CPTSD, and those without symptoms.

A total of 7.7% (95% CI 4.5–12) of the male sentenced prisoners met diagnostic criteria for ICD-11 PTSD and 16.7% (95% CI 12.1–22.3) for CPTSD. A diagnosis of PTSD was associated with more recent traumatic exposure, comorbid generalised anxiety disorder, alcohol dependence, and Cluster B personality disorder. A diagnosis of CPTSD was associated with complex trauma exposure antecedents (developmental, interpersonal, repeated, or multiple forms), and comorbid with anxiety, depression, substance misuse, psychosis, and ADHD.

This study confirms that CPTSD is a very common and comorbid condition in male prisoners. There is an urgent need to develop trauma-informed care in prisons.

There is controversy over the extent to which the new International Classification of Diseases (ICD-11) diagnosis of complex posttraumatic stress disorder (CPTSD) is distinct from posttraumatic stress disorder (PTSD). This study aimed to conduct the first investigation of distinctive neural processes during threat processing in CPTSD relative to PTSD.

This cross-sectional functional magnetic resonance study included 99 participants who met criteria for PTSD (PTSD = 32, CPTSD = 28) and 39 trauma-exposed controls. PTSD was assessed with the Clinician-Administered PTSD Scale (CAPS). CPTSD was assessed with an adapted version of the International Trauma Questionnaire. Neural responses were measured across the brain while threat or neutral faces were presented at both supraliminal and subliminal levels.

During supraliminal presentations of threat stimuli, there was greater bilateral insula and right amygdala activation in CPTSD participants relative to PTSD. Reduced supraliminal right dorsolateral prefrontal cortex activation and increased subliminal amygdala and insula activation were observed as common dysfunction for both CPTSD and PTSD groups relative to trauma controls. There were no significant differences in terms of subliminal presentations and no differences in functional connectivity. Dissociative responses were positively associated with right insula activation (r = 0.347, p < 0.01).

These results provide the first evidence of distinct neural profiles of CPTSD and PTSD during threat processing. The observation of increased insula and right amygdala activation in CPTSD accords with the proposal that CPTSD is distinguished from PTSD by disturbances in emotion regulation and self-concept.