Postictal psychosis coexisting with forced thinking

1. Case Report 

A 22-year-old right-handed male had a 10-year history of medically intractable complex partial seizures with an infrequent secondary generalization. Despite a careful adjustment of the plasma level of carbamazepine and phenytoin, he continued to have 3–5 seizures a month. The other antiepileptics were less effective. At the onset of habitual seizures, he complained of a variety of psychic auras including reminiscence; a feeling of someone being nearby; illusion of familiarity (déjà vu or jamais vu); a feeling that the world is going to change; and forced thinking about religious matters, e.g., the meaning of the existence of God and the human race. He also described during the aura phase that he finally realized the true nature of the cosmos. Subsequently, he exhibited a staring expression, speech arrest and orobuccal automatisms under a cloud of consciousness. He then remained confused for 5–15 min, rushing or moving around.

He had no prior medical history including febrile convulsions. He was active and maintained normal social interactions. A distant relative suffered from seizures.

On examination he was alert and cooperative. General physical and neurological findings were unremarkable. Full blood count, liver and renal function tests, and the plasma level of electrolytes were normal except for hyponatremia (124–130 mEq/L). Surface and sphenoidal electroencephalography (EEG) showed ictal theta waves with phase reversal at the right sphenoidal lead (Fig. 1). Interictally, sharp waves with phase reversal were found at the same lead. Magnetic resonance imaging (MRI, 1.5 tesla) demonstrated no signal abnormalities. MRI volumetry showed no marked hippocampal asymmetry [8]. Single photon emission computed tomography with Technetium-99 m labeled hexamethyl propylene amine oxime, performed in an interictal period, did not reveal hyper- nor hypo-perfusion areas. He had a full-scale IQ of 86, verbal IQ of 76, and performance IQ of 102 on the Wechsler Adult Intelligence Scale-Revised.

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Fig. 1. Ictal EEG showing theta bursts with phase reversal at the right sphenoidal lead. SP1 and SP2 indicate the left sphenoidal lead and the right sphenoidal lead, respectively.

He first developed PIP at age 17 and then averaged 1–2 episodes a year. The psychosis occurred after an exacerbation in seizure frequency and/or seizure intensity, particularly after a run of secondarily generalized seizures, and was unrelated to the withdrawal from antiepileptic agents. An interval ranging from 1 to 2 days intervened between the end of the seizures and the onset of psychosis, during which he was fully oriented and able to give an accurate description of current events and his life history, suggesting no impairment of consciousness.

At the onset of PIP, he almost invariably experienced forced thinking in which many strange thoughts came crowding into his mind, such as “what is death?” or “why does the human race exist?” He also described a feeling that his mind was speaking to him. Furthermore, he felt compelled to think of contrary terms including “black and white” or “life and death.” He realized the unreal nature of forced thinking. Subsequently he became severely restless and incoherently cried: “The world is over. My father created the earth. Why does God exist? The earth is bombing.” He then gradually calmed down over several days and in turn developed a religious and grandiose delusion in the setting of an entranced mood: “I have special power because I was born to be God. I am responsible for keeping world peace. I can make people happy. My thoughts influence the universe, resulting in disasters.” The complaint of forced thinking was also found in this phase.

In addition, he experienced hypergraphia and described auditory hallucinations of an accusatory voice or a feeling of someone being nearby. The duration of the psychosis ranged between 1 and 2 weeks under antiepileptic (carbamazepine and/or phenytoin) medication with or without the use of neuroleptics (haloperidol or chlorpromazine). After each episode, he was able to recall most events that had occurred during the delusional phase but not those during the incoherent phase. It was impossible to perform EEG during the incoherent phase. During the delusional phase, surface EEG showed that alpha activity was replaced intermittently by 5–6 Hz of theta activity lasting 1–10 seconds without localization. During psychotic episodes, to avoid self-harm, sphenoidal electrodes were not used.

Recently, a few studies have attempted to characterize the phenomenology of PIP. For example, PIP tends to occur after a run of complex partial seizures, lasts 1 to 2 weeks, and tends to recur [2]. A lucid interval with no evidence of psychopathology often precedes the onset of PIP, likely differentiating the psychosis from postictal confusion [2], [3]. Grandiose and religious delusions with elevated mood have also been described [2], [3], [4]. In addition, PIP is closely associated with temporal lobe epilepsy [3], [4], [5], [7], [9]. Our PIP patient demonstrated all of these features.

Kanemoto et al. [3] report that the incidence of psychic auras was high in PIP patients and that the classic triad of the dreamy state of Jackson and Stewart (mental diplopia, reminiscence, and a feeling of impending death) [10] was relatively common in PIP episodes. Based on these findings, the authors suggested an intimate interrelation between PIP and aura phenomenology. Supporting this hypothesis, our patient characteristically developed forced thinking in PIP episodes as well as in aura episodes. In both episodes, the complaint of a feeling of someone being nearby was also observed. Furthermore, forced thinking is interpreted as a form of mental diplopia. Patients complaining of mental diplopia realize its unreal nature, as did our patient. Thus, further studies to determine the incidence of symptoms known as psychic auras in the psychotic phase of PIP and other epileptic psychoses may contribute to a better understanding of their phenomenological differences.

This point of view is also relevant to a discussion of whether epileptic psychosis is due to neuronal exhaustion (similar to Todd’s palsy) or to ongoing seizure activities [2], [5], [7]. Forced thinking stressed here, for example, is an epilepsy-specific symptom originating in the frontal or temporal lobe [11], [12], [13]. Indeed, forced thinking can be evoked by amygdaloid electrical stimulation [13]. Our PIP patient had a seizure origin likely located in the right mesial limbic structures, supported by a variety of psychic auras followed by automatisms and an ictal EEG showing theta waves arising from the mesial limbic structures. Therefore, our patient’s PIP cannot be regarded as a Todd’s equivalent and there is a possibility that it may have been caused by limbic ictal discharges. Kanemoto et al. [3] also surmised in the above-mentioned study that PIP represents an intensive propagation of the habitual seizure symptomatology. Taken together, a definite line of demarcation cannot be drawn between PIP and seizures preceding it. The psychosis referred to as PIP might be an ictal event rather than a postictal event.