Neuropsychiatric Symptoms of Epilepsy

19 The Role of Stimulation Techniques
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elevated [ 39 ]; and the rates are substantially higher in patients with both epilepsy
and psychogenic non-epileptic seizures [ 40 ]. One study found evidence for the
development of PTSD following epileptic seizures, with the severity of the symptoms
related to difficulty in identifying internal feelings and emotions [ 41 ]. The
lifetime prevalence of PTSD in community cohorts is up to 8 % [ 32 , 42 ]. Symptoms
of PTSD occur with re-experiencing the traumatic event, avoidance, and hypervigilence,
and include hyperarousal, intrusive thoughts, flashbacks, emotional numbness,
and sleep disturbances, including nightmares.
Psychosis
Psychosis occurs in 0.6–7 % of community-based PWE and 19–27 % of hospitalized
PWE [ 43 ]. Psychosis may occur before or after epilepsy onset, consistent with
a bidirectional relationship [ 5 ]. Epilepsy-related risk factors include TLE, particularly
left TLE due to mesial temporal sclerosis [ 44 , 45 ].
Psychosis may occur inter-ictally, which is the most common presentation, or
emerge with forced normalization, for example, after epilepsy surgery [ 46 ].
Psychotic symptoms may also be present during or after seizures, especially the first
72 h of the post-ictal period [ 12 ], typically in patients with bilateral independent
ictal foci [ 47 ] and following a cluster of seizures or status epilepticus. Symptoms
may last up to several weeks and include visual or auditory hallucinations, paranoia,
delusions, confusion, affective changes, amnesia, and violence. Violent behavior
may be purposeful and directed in response to hallucinations or delusions towards
those nearby [ 48 , 49 ]. Post-ictal violent behavior may also result when a person is
restrained after a seizure, called “resistive violence” [ 50 ], and typically seen in
those with CNS pathology, mental retardation, and comorbid psychiatric illness.
Neuropsychiatric Effects of Brain Stimulation
This section describes the effects of brain stimulation on the neuropsychiatric symptoms
discussed in the previous section as well as on similar symptoms in patients
with psychiatric disorders but without epilepsy, where applicable.
Vagus Nerve Stimulation
Vagus nerve stimulation (VNS) with the VNS Therapy system (Cyberonics, Inc.) is
a non-pharmacological, surgically implanted, device-based therapy approved in
1997 by the FDA as an adjunctive therapy in reducing the frequency of seizures in
adults and adolescents over 12 years of age with partial onset seizures not controlled
by medication or who experience intolerable side effects. In 2005, the FDA approved
VNS as an adjunctive long-term treatment of chronic or recurrent depression for