Neuropsychiatric Symptoms of Epilepsy

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% of sibling controls. Hermann et al. [ 37 ] found that 82 % of the children with newonset
seizures and ADHD had evidence of ADHD prior to first seizure.
One possible explanation for the association of epilepsy and ADHD is a common
genetic vulnerability. The genetic bases of ADHD and epilepsy are being rapidly
defined by use of genome-wide association studies. The rapid progress in genetics
suggests possible links between epilepsy and ADHD. Lo-Castro and Curatolo [ 72 ]
reviewed prior studies and found genes involved in synapse formation, neurotransmission,
and DNA methylation and remodeling that conveyed vulnerability for epilepsy
and ADHD. In a small sample of 16 mothers of children with epilepsy and
ADHD, 8 of the 16 mothers had a current or past history of ADHD [ 73 ]. In contrast,
Hesdorffer et al. [ 74 ] assessed family history of behavioral problems in first degree
relatives of patients with seizures. They found a familial clustering of symptoms of
multiple behavioral problems in patients with unprovoked seizures, but did not find
an increase in attention problems or ADHD in relatives.
Underlying central nervous system damage may be a factor in both epilepsy and
ADHD. One epidemiological study found that ADHD was significantly more common
in children with complicated epilepsy compared to those with no additional
neurological impairment [ 25 ]. The two clinical series reported on symptoms in children
with severe epilepsy. Ferrie et al. [ 75 ] found hyperactivity in 77 % of children
with intractable epilepsies and Sherman et al. [ 45 ] noted ADHD in 71 % of children
being assessed for seizure surgery or having severe epilepsy.
Children with epilepsy and ADHD have been assessed with structural and functional
imaging. One group initially found increased gray matter in the frontal lobes
of children with epilepsy and ADHD, but later reported an association between
symptoms of attention problems and decreased cortical thickness in the frontal and
left parietal lobes and an association between higher ADHD scores and decreased
cortical thickness in the frontal and occipital lobes [ 37 , 76 ]. Functional magnetic
resonance imaging (fMRI) has been used to assess attention and executive function.
Bechtel et al. compared boys with epilepsy and ADHD and boys with ADHD alone.
They found similar areas of reduced activation in response to a working memory
task in the two groups [ 55 ]. Killory et al. [ 77 ] evaluated attention in children with
absence epilepsy and found reduced activity in the medial frontal cortex and
impaired connectivity between the medical frontal cortex and the right anterior
insula/frontal operculum. Using fMRI, McGill et al. [ 78 ] studied the default mode
network and found decreased functional connectivity between the cingulate cortex
and frontal lobe similar to what would be found in patients with impaired
attention.
Successive Comorbidity
Potential reasons for successive comorbidity could include impaired attention and
executive function secondary to seizures, to adverse effects of antiepileptic drugs, or
to psychological or social reactions to having seizures. Seizure-related variables