Trait impulsivity in Juvenile Myoclonic Epilepsy

Abstract

Objective: Impulsivity is a multidimensional construct that can predispose to psychopathology. Meta-analysis demonstrates an association between response impulsivity and Juvenile Myoclonic Epilepsy (JME), a common genetic generalized epilepsy. Here, we test the hypotheses that trait impulsivity is (i) elevated in JME compared to controls; (ii) moderated by specific seizure characteristics; and (iii) associated with psychiatric adverse effects of antiepileptic drugs (AEDs).

Methods: 322 participants with JME and 126 age and gender-matched controls completed the Barratt's Impulsiveness Scale (BIS-brief) alongside information on seizure history and AED use. We compared group BIS-brief scores and assessed associations of JME BIS-brief scores with seizure characteristics and AED adverse effects.

Results: The mean BIS-brief score in JME was 18.1 ± 4.4 compared with 16.2 ± 4.1 in controls (P = 0.0007). Elevated impulsivity was associated with male gender (P = 0.027), frequent absence seizures (P = 0.0004) and lack of morning predominance of myoclonus (P = 0.008). High impulsivity significantly increased the odds of a psychiatric adverse event on levetiracetam (P = 0.036), but not any other psychiatric or somatic adverse effects.

Interpretation: Trait impulsivity is elevated in JME and comparable to scores in personality and neurotic disorders. Increased seizure frequency and absence of circadian seizure pattern moderate BIS score, suggesting disruption of both cortico-striatal and thalamocortical networks as a shared mechanism between seizures and impulsivity in JME. These findings warrant consideration of impulsivity as a distinct target of intervention, and as a stratifying factor for AED treatment in JME, and perhaps other types of epilepsy. The role of impulsivity in treatment adherence and psychosocial outcome requires further investigation.

Figure 1

The correlation between BIS‐brief and BIS‐11 scores in 92 JME participants. The solid line is the regression line (y = 24.2 + 2.3*X). Blue dashed lines show 95% confidence intervals of regression line. R_S = 0.85.

Figure 2

A, The mean BIS‐brief scores in our JME and control cohorts compared to other neuropsychiatric and control populations from the literature. Adjusted p‐values comparing the mean score from each group to the JME cohort are presented. Adolescent controls n = 356; adult controls n = 128; adult domestic abusers n = 111; Family history (FH) of substance abuse n = 302; adolescent psychiatric inpatients n = 322; JME n = 322; collected controls n = 126. B, Mean BIS‐11 scores of a range of control and clinical cohorts from previous literature categorized by disease type. Error bars show 95% confidence intervals. (ADHD, Attention‐deficit/hyperactive disorder; JME, Juvenile Myoclonic Epilepsy; OCD, Obsessive Compulsive Disorder).

Figure 3

BIS‐brief score comparison between clinical variables included in the multiple linear regression model. ‘+’ shows mean per group, boxes show upper and lower interquartile range with median marked by the central line. Error bars show 95% confidence intervals with outliers presented as individual dots.