Abstracts

Rationale: Morbidities that predispose individuals to unprovoked seizures are relatively understudied. We examined individual patients’ medical histories prior to the first-ever unprovoked seizure to identify potential physical and psychological conditions associated with an increased risk of seizures.


Methods: Patients who had their first-ever unprovoked seizure and were seen at First Seizure Clinics (FSC) in Western Australia (WA) between May 1, 1999, and May 31, 2016, were linked with statewide healthcare databases. Population controls without seizures were randomly sampled from 1% of the WA electoral roll over the same period and matched by year of birth and sex. Discharge diagnoses from hospital admissions and emergency department presentations from January 1, 1970, and psychological diagnoses from mental health outpatient clinic visits from July 1, 1966, were extracted up to the end of 2019. Logistic regressions were used to identify physical and psychological conditions associated with the development of first seizure, with adjustments for sex and year of birth.


Results: A total of 1,287 patients with a first-ever unprovoked seizure (62.8% male), and 13,468 matched controls (49.5% male) were analyzed. Among patients with seizures, injury (n=656, 51.0%), especially head injury (n=283, 22.0%), was the most common pre-existing morbidity, and the proportion was significantly higher than in the controls (Table 1). Brain tumor, hemiplegia, and cerebrovascular disease were also strongly associated with the development of the first unprovoked seizure. Psychological disorders, including sub-diagnoses such as substance misuse, psychosis, depression, and stress, as well as the utilization of mental health outpatient services, all demonstrated significant associations with unprovoked seizures.

Healthcare utilization in the one year before and after the first-ever unprovoked seizure in patients with seizures or the matched index month in controls was assessed. Patients with seizures showed an increase in healthcare utilization frequency over the preceding year, compared to controls (Figure 1). This increasing trend was not statistically significantly different between patients with or without pre-existing morbidity, though the former had consistently higher healthcare utilization frequency than the latter. The healthcare utilization frequency peaked at the month of the first-ever unprovoked seizure, as expected, and gradually reduced over the following 12 months but remained higher than in the year before the seizure.


Conclusions: Conditions that can manifest in the central nervous system or symptoms indicating underlying neurological damage, i.e., causal comorbidities, elevate the risk of developing unprovoked seizures, an expected finding. Psychological disorders are associated with the development of seizures, though the mechanism of this association warrant further investigation. Along with increased healthcare utilization, these conditions may serve as early warnings of impending seizures. Understanding these associations may aid in the early identification and management of individuals at risk for unprovoked seizures.


Funding: The study received no specific funding.