Neuropsychiatric Symptoms of Epilepsy

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M. Beghi et al.
Table 16.1 Age-adjusted odds ratios (ORs) with 95 % confidence intervals (CIs) for development
of unprovoked seizures after a first discharge diagnosis of depression, psychosis, bipolar disorder,
anxiety disorder, suicide attempt, or psychiatric disorders combined [ 1 ]
Symptomatic
Cryptogenic/idiopathic
Diagnosis OR 95 % CI OR 95 % CI
Depression 1.5 0.8–2.6 3.9 2.4–6.1
Psychosis 2.1 1.2–3.9 2.5 1.4–4.4
Bipolar disorder 2.3 0.9–5.6 3.3 1.4–7.9
Anxiety disorder 1.4 0.6–3.6 4.0 2.1–7.6
Suicide attempt 1.2 0.5–2.8 3.9 2.4–6.2
Psychiatric disorders combined a 1.9 1.3–2.9 3.5 2.5–5.0
Reprinted with permission Wolters Kluwer Health, from Adelöw et al. [ 1 ], © 2012
Abbreviations : CI confidence interval, OR odds ratio
a
The diagnosis psychiatric disorders combined includes all the other diagnoses except suicide
attempt, for which each patient can have more than one psychiatric diagnosis
Introduction
Despite an abundant literature exploring psychiatric disorders in epilepsy, little is
known on the epidemiology of epilepsy in psychiatric disorders. Some recent studies
[ 1 , 2 ] found an increased rate of psychiatric comorbidity preceding epileptic
seizure onset and indicating a bidirectional relationship and common underlying
mechanisms lowering seizure threshold and increasing the risk for psychiatric disorders
and suicide (Table 16.1 ). In this chapter we make a summary of the available
evidence on this topic, trying to explain the underlying mechanisms.
Neurodevelopmental Disorders and Epilepsy
Intellectual disability (ID), the term used instead of the previous one of mental retardation,
might be not properly considered a psychiatric disorder, but it has been
always included in the psychiatric disorders category, both in the Diagnostic and
Statistical Manual (DSM) [ 3 ] and in the International Classification of Diseases
(ICD) [ 4 ]. The fifth recent edition of DSM [ 3 ] uses, in the broader category of
“Neurodevelopmental Disorders,” the term “intellectual developmental disorders”
(IDD), pointing out two substantial concepts: first of all the “IDD” is no longer
considered a “disability” but a “disorder”; second, the term strongly links the symptoms
to the brain evolution process. About this aspect, cognitive or behavioral disorders
are associated and lie under the same etiopathogenic mechanism. This is thus
the only condition strongly related to epilepsy in terms of diagnosis, prognosis, and
treatment [ 5 ]. The comorbidity between IDD and epilepsy is high. Around 20 % of
people with IDD develop seizures with a stable prevalence during the last decades
[ 6 , 7 ]. The risk for epilepsy increases with the severity of ID [ 8 ]. In patients with ID,
generalized seizures are more common than partial seizures (63 % vs 33 %) [ 9 ].