Dorothea Bindman and Jackie Foong Psychiatric symptoms occur in over half of the people with epilepsy seen at tertiary centres. Comorbid psychiatric conditions are essential to recognise and treat as they can harm functional status and quality of life.1 There is increasing evidence that affective disorders, such as depression, anxiety, and neurodevelopmental disorders (ADHD and autism), share common aetiological factors with epilepsy, and often have a bidirectional relationship. Depression and anxiety can precede the onset of seizures by several years. Psychiatric symptoms can be classified according to how they relate in time to seizure occurrence, namely peri‐ictal (preictal/ictal/postictal) or interictal. Preictal affective symptoms can present days before a seizure and range from mild irritability to significant anxiety and dysphoria. Psychic symptoms during the ictus are often associated with temporal lobe seizures and usually occur alongside impaired awareness and automatisms. In some people, ictal fear may be the only manifestation of focal seizures with retained consciousness. These are often under‐recognised and can be misdiagnosed as a panic attack, mood disturbances, including depression, mania, and anxiety. Postictal anxiety commonly occurs in nearly half of people with epilepsy. There is often a history of interictal psychiatric disorder. Symptoms typically last for less than one week, but postictal mania can persist longer. These disorders are common in people with epilepsy, especially those with drug‐resistant epilepsy (DRE). The psychosocial burden of seizures is a significant factor, and an underlying neurobiological relationship between epilepsy and affective disorders is likely. Depressive disorders can present atypically, and the term ‘interictal dysphoric disorder’ has been used. It remains uncertain whether this is a distinct clinical entity.2 In interictal dysphoric disorder, mood can be more variable than in a typical depressive episode, and there can be occasional periods of elevated mood. Features such as irritability, anxiety, and insomnia may be prominent. The symptom complex has similarities to mood disturbance seen in other chronic neurological diseases and can resemble the primary psychiatric mood disorder, cyclothymia. Bipolar mood disturbance is less common than depressed mood in people with epilepsy, but can present in the preictal or postictal phase,3 or as a side effect of antiseizure medications (ASM). It is not yet clear whether the excess of bipolar mood symptoms identified in people with epilepsy represents an increased incidence of bipolar affective disorder or an atypical mood disorder. Interictal anxiety is probably under‐recognised in people with epilepsy4 and may co‐exist with atypical depressive symptoms. Anxiety disorders often meet DSM and ICD criteria for generalised anxiety disorders and specific phobias, but usually include seizure phobia. The classical features of anxiety disorders, anticipatory anxiety and avoidance may centre around a fear of a seizure being witnessed by others or of an injury, leading to avoidance of specific environmental situations. Severe illness may require a combination of pharmacological and psychological treatments. This also applies to specific anxiety disorders such as seizure phobia and panic disorder.1, 4 Serotonin and noradrenaline reuptake inhibitor antidepressants are usually well‐tolerated and safe, as are most of the newer atypical agents. Bupropion, a noradrenaline and dopamine reuptake inhibitor, is an exception as it can trigger seizures. Tricyclic antidepressants, in particular clomipramine, may also increase the risk of seizures. Psychological therapies, such as cognitive‐behavioural therapy, are often highly beneficial. Psychotic disorders can be a severe comorbidity of epilepsy. Recent meta‐analyses report an overall prevalence of up to seven per cent.5 It is essential to clarify how psychotic symptoms relate to seizure occurrence or ASM, as this will guide management. Preictal psychotic symptoms are poorly understood. Symptoms include depersonalisation, derealisation, persecutory ideation, and hallucinations. These symptoms can appear hours or even days before a seizure. They resolve with the seizure and do not generally require psychotropic medications. They may provide a helpful warning of an episode that may be prevented with a short course of clobazam. Ictal psychotic symptoms include mood, perceptual and behavioural disturbances that occur as part of the seizure. There is usually impaired awareness and little recall of the event. Other ictal features, such as automatisms, are common. Visual, gustatory, or auditory hallucinations are generally not well‐defined. The episodes are brief, beginning and ending abruptly. Ictal psychotic symptoms are mainly observed in people with TLE. The psychotic symptoms resolve on termination of the seizure, so antipsychotic medications are usually not needed. The prevalence has been estimated to be as high as ten per cent, particularly in TLE. Postictal psychosis is more likely to occur following a cluster of focal impaired awareness seizures, focal convulsive seizures, or status epilepticus. Typically, there is a 12–72 hour lucid period before the onset of psychotic symptoms. Psychotic symptoms may include paranoid, grandiose, political or religious delusions, hallucinations, manic behaviour, and aggressive or suicidal behaviour. Postictal psychotic symptoms are usually transient, lasting a few days, but may last several weeks. Acute benzodiazepines in a seizure cluster may prevent the development of postictal psychosis. If psychosis develops, a short course of antipsychotics such as risperidone is usually adequate. Some people with recurrent postictal psychosis subsequently develop a chronic interictal psychosis. The pathophysiological mechanisms of postictal psychosis are unclear but likely involve widespread brain dysfunction. Risk factors include bilateral epileptic foci, diffuse structural brain abnormalities, and possible genetic mechanisms.6, 7 The psychotic episode can remit spontaneously, but treatment with short courses of benzodiazepines or antipsychotics may be required in more severe or prolonged episodes. The prevalence of interictal psychosis is up to ten per cent in people with epilepsy, predominantly in those with TLE.8 This chronic disorder resembles primary schizophrenia with symptoms of delusions, hallucinations, or thought disorder.9 Premorbid personality is better preserved, and negative symptoms are less prominent in interictal psychosis than in schizophrenia. The onset of the psychosis is variable and usually occurs after at least a decade of epilepsy. Risk factors are early age of onset of epilepsy, bilateral temporal foci, a refractory course, and possible neurodevelopmental factors. Complex pathophysiological mechanisms are probably involved, implicating focal and generalised brain abnormalities.10–12 A review of studies in TLE and psychosis suggested that temporal lobe abnormalities may not be solely involved, and other networks, such as frontotemporal, are probably also implicated.13 Treatment with antipsychotic medications is usually long‐term.14 Atypical or second‐generation antipsychotic drugs (e.g. risperidone, olanzapine) are recommended in preference to the typical agents as they are less likely to reduce seizure threshold, apart from clozapine, or cause extrapyramidal side effects. Lower doses than those used in primary schizophrenia are generally effective. Psychosocial support and family education are necessary.
CHAPTER 23
Neuropsychiatric Aspects of Epilepsy
MOOD AND ANXIETY DISORDERS
PERI‐ICTAL MOOD DISTURBANCE
INTERICTAL MOOD AND ANXIETY DISORDERS
Mood disorders
Anxiety disorders
Treatment
PSYCHOTIC DISORDERS
PREICTAL OR PRODROMAL
ICTAL
POSTICTAL PSYCHOSIS
INTERICTAL PSYCHOSIS
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