Genetic evidence for behavioral preference factors on fatigue: A Mendelian randomization study of chronotype, morning alertness, and outdoor exposure.

Childhood emotional maltreatment (CEM) is increasingly recognised as an important risk factor for trauma-related outcomes (Gama et al., ; Hashim, Alimoradi, et al., ; Peter et al., ), yet its specific association with posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) remains insufficiently characterised. PTSD affects millions worldwide and is associated with substantial functional impairment and chronic disability (Koenen et al., ; Ressler et al., ). Epidemiological data indicate a lifetime prevalence of approximately 4-6%, with rates reaching 25–30% following severe psychological trauma (Ressler et al., ). Similarly, pooled prevalence estimates across trauma-exposed populations approach 24% (Schincariol et al., ). Despite the availability of evidence-based pharmacological and psychotherapeutic treatments (Billings & Nicholls, ; Fares-Otero et al., ; Hoppen et al., ), many individuals experience only partial recovery, with persistent symptoms, reduced quality of life, and elevated risk of comorbidity, suicide and medical condition, including cardiovascular and metabolic diseases (Ressler et al., ; Sareen et al., ; Shea et al., ). These limitations highlight the need to better understand the factors associated with the onset and persistence of trauma-related disorders, to guide prevention and intervention strategies. PTSD and CPTSD represent two key trauma-related outcomes, with CPTSD recently introduced in the International Classification of Diseases, 11th Edition (Brewin et al., ; Fung et al., ). PTSD captures core responses to traumatic exposure, characterised by re-experiencing, avoidance, hyperarousal and negative alterations in cognition and mood (McHugh & Treisman, ; Shalev et al., ). CPTSD includes additional disturbances in self-organisation, including affective dysregulation, negative self-concept and relational difficulties, occurring alongside the core symptoms of PTSD (Maercker et al., ). While single-event traumas such as natural disasters or accidents can precipitate PTSD, CPTSD more often arises from repeated or prolonged interpersonal trauma, including childhood abuse or violence in adulthood (Huynh et al., ; Karatzias et al., ).