Dissociative symptoms may result from both neurobiological conditions, such as Attention-Deficit/Hyperactivity Disorder (ADHD), and traumatic events/exposure, such as Post-Traumatic Stress Disorder (PTSD) and Adverse Childhood Experiences (ACEs). However, identifying whether dissociative manifestations are associated with ADHD symptoms or trauma-related manifestations may drive clinicians to select the most effective intervention. Four hundred participants from the general population completed an online survey and were classified based on the presence of PTSD, ACEs, or ADHD symptoms. We compared the severity of dissociation and its dimensions across groups using the Dissociative Experiences Scale-II (DES-II) and explored its association with ADHD symptoms, PTSD manifestations, and ACEs. Dissociative symptoms were more pronounced in individuals with combined ADHD and PTSD or ACEs, but a hierarchical pattern of dissociation severity was also observed in isolated symptoms: ADHD > PTSD > ACEs. More specifically, participants who reported ADHD symptoms obtained higher scores on the Amnesia dimension of the DES-II than PTSD and more severe Absorption subscores than individuals reporting ACEs. Correlational analyses confirmed that DES-II scores were mostly associated with the scale evaluating the severity of ADHD symptoms rather than those evaluating trauma-related manifestations. These findings suggest that neurodevelopmental vulnerabilities, such as ADHD, may play a more significant role in dissociative symptomatology than trauma-related disorders.