Epilepsy, a severe neurological disorder impacting approximately 50 million individuals worldwide, is associated with a high prevalence of mental health issues. However, existing research has predominantly examined the relationship between epilepsy and depression or anxiety, neglecting other dimensions of mental health as assessed by factor scores from the general health survey (GHQ), such as the GHQ-12. This study aimed to explore how epilepsy affects both general mental health and specific dimensions of mental health. By employing a factor analysis and a predictive normative modeling approach, the study examined 426 epilepsy patients and 39,171 individuals without epilepsy. The findings revealed that epilepsy patients experienced poorer general mental health and specific aspects of mental health. Consequently, this study highlights the validity of GHQ-12 as a measure of mental health problems in epilepsy patients and emphasizes the importance of considering the impact of epilepsy on various dimensions of mental health, rather than focusing solely on depression or anxiety. Clinicians should incorporate these study results into the development of interventions aimed at enhancing mental well-being in epilepsy patients, ultimately leading to improved outcomes.