Effects of antipsychotic drugs on the duration of interictal psychotic episodes in patients with epilepsy

Epilepsy and psychosis

Psychotic disorders are eight times more frequent in epilepsy than in the general population. The various clinical syndromes are classified according to their chronology of onset in relation to epileptic seizures: ictal psychoses (during epileptic discharge), post-ictal psychoses (PIP, after a seizure), interictal psychoses (IIP, with no chronological link) and those related to complete seizure control. Antiepileptic drugs can cause psychotic disorders in all these situations. Post-ictal psychoses (PIP) are affective psychoses that occur after a lucid interval lasting 12 to 120hours following a cluster of seizures. They last an average of 10days, with an abrupt beginning and end. PIP are directly linked to epileptic seizures, and disappear when the epilepsy is controlled. Interictal psychoses are schizophrenias. The management of psychotic disorders in epilepsy is neuropsychiatric, and requires close collaboration between epileptologists and psychiatrists. Antipsychotics can be prescribed in persons with epilepsy. Even today, psychotic disorders in epilepsy are poorly understood, under-diagnosed and under-treated.

[Interictal psychosis of epilepsy]

Interictal psychosis (IIP) refers to psychosis that occurs in clear consciousness in persons with epilepsy (PWE) with temporal onset not during or immediately following a seizure. The pooled prevalence estimate of psychosis in PWE is 5.6%. PWE and schizophrenia have very high mortality, and more than one in four persons with both disorders die between the age of 25 and 50years. IIP can manifest in brief or chronic forms. The chronic forms of IIP may closely resemble schizophrenia. However, some authors have described the typical presence of persecutory and religious delusions, sudden mood swings and the preservation of affect, as well as rarity of negative symptoms and catatonic states, but these differences remain controversial. Typically, IIP starts after many years of active temporal lobe epilepsy. Several epilepsy-related variables are considered pathogenically relevant in IIP including epilepsy type and seizure characteristics. Risk factors for developing IIP are family history of psychosis, learning disability, early age of onset of epilepsy, unilateral or bilateral hippocampal sclerosis, history of status epilepticus, history of febrile seizures, and poorly controlled temporal lobe epilepsy. In patients with epilepsy and psychosis, structural imaging studies have shown several relevant changes leading to conflicting findings. Altered neuronal plasticity and excitability have been described in epilepsy and psychotic disorders. Neuropathological data suggest that IIP are not the result of classic epileptic pathology of the temporal lobe. Forced normalization (FN) and alternating psychosis refer to patients with poorly controlled epilepsy (focal or generalized) who have had psychotic episodes associated with remission of their seizures and disappearance of epileptiform activity on their EEGs. FN mainly occurs in temporal lobe epilepsy when patients have frequent seizures that are abruptly terminated triggered by an antiepileptic drug, vagus nerve stimulation or epilepsy surgery. Treatment is based on withdrawal of the responsible drug, and by transient use of antipsychotics for acute symptomatic control on a case-by-case basis. FN is an entity whose pathophysiology remains uncertain. Antiepileptic drugs (AEDs) may sometimes induce psychotic symptoms and psychosis could be a direct effect of the AEDs. IIP has been reported more frequently following the initiation of zonisamide, topiramate, and levetiracetam when compared with other antiepileptic drugs. However, AEDs do not appear to be the only determinant of IIP. The management of IIP requires a multidisciplinary approach with early involvement of a liaison psychiatrist associated with a neurologist. IIP are underdiagnosed and mistreated. Existing recommendations are extrapolated from those established for the treatment of schizophrenia with some additional guidance from expert opinions. A two-step procedure, not necessarily consecutive, is suggested. The first step requires reevaluation of the antiepileptic treatment. The second step requires initiation of atypical neuroleptics. Antipsychotic drugs should be selected with consideration of the balance between pharmacological profiles, efficacy, and adverse effects. Regarding pharmacokinetic interactions, AEDs with inducing properties reduce the blood levels of all antipsychotics. It is important to consider implications of combining neuroleptics and AEDs with a similar spectrum of side effects. Regarding the duration of treatment, IIP episodes are more likely to be recurrent than in primary schizophrenia. In practice, atypical neuroleptics with few motor side effects such as risperidone can be used as first choice, given the low propensity for drug-drug interactions and the low seizure risk, with the added suggestion to start low and go slow. Clozapine could be prescribed in selected cases.

Psychosis in adults with epilepsy and its relationship to demographic, clinical and treatment variables

Objectives: Psychiatric symptoms and disorders are commonly reported with epilepsy. This study aimed to determine the prevalence of interictal psychosis (IIP) in adults with epilepsy and its risk predictors. Methods: The study included 710 patients (mean age: 36.40 years; age at onset: 13.58 years; duration of epilepsy: 22.80 years). All underwent neurological and psychiatric interviewing, electroencephalography and brain imaging. Results: IIP was reported in 20.65%, of them 50% had temporal lobe epilepsy with impaired awareness and/or to bilateral tonic clonic, 42.47% had frontal lobe epilepsy with impaired awareness and/or to bilateral tonic clonic and 7.53% had generalized tonic-clonic seizures. Compared to patients without psychosis, patients with psychosis were older at age of examination, had earlier age at onset, frequent seizures, longer duration of epilepsy and long-term antiepileptic drugs therapy and many relatives with epilepsy. Nearly 76.71% had history of postictal psychosis (PIP). The mean age of onset of IIP was 30.45 years and its mean duration was 3.84 months. Approximately 22% of patients with IIP had family history of psychosis. Patients developed IIP 10 years or more after epilepsy onset. Multivariate logistic regression analyses showed that predictors for IIP were the age at onset and duration of epilepsy, number of seizures, family history of epilepsy or psychosis, history of PIP and different types of epilepsy. Conclusion: IIP is not infrequent with chronic epilepsy regardless to its type. These findings emphasize the importance of optimizing patients' treatment and early recognition and management of IIP. Abbreviations: IIP: interictal psychosis; PIP: post-ictal psychosis; TLE: temporal lobe epilepsy; FLE: frontal lobe epilepsy; GTC: generalized tonic clonic; AEDs: antiepileptic drugs; CBZ: carbamazepine; VPA: valproate; LEV: levetiracetam; APDs: antipsychotic drugs.

Pharmacotherapy in patients with epilepsy and psychosis

The recognition and treatment of psychosis in persons with epilepsy (PWE) is recommended with the apparent dilemma between treating psychosis and opening the possibility of exacerbating seizures. The pooled prevalence estimate of psychosis in PWE is 5.6%. It has been proposed that a 'two hit' model, requiring both aberrant limbic activity and impaired frontal control, may account for the wide range of clinical phenotypes. The role of antiepileptic drugs in psychosis in PWE remains unclear. Alternating psychosis, the clinical phenomenon of a reciprocal relationship between psychosis and seizures, is unlikely to be an exclusively antiepileptic drug-specific phenomenon but rather, linked to the neurobiological mechanisms underlying seizure control. Reevaluation of antiepileptic treatment, including the agent/s being used and degree of epileptic seizure control is recommended. The authors found very few controlled studies to inform evidence-based treatment of psychosis in PWE. However, antipsychotics and benzodiazepines are recommended as the symptomatic clinical treatments of choice for postictal and brief interictal psychoses. The general principle of early symptomatic treatment of psychotic symptoms applies in epilepsy-related psychoses, as for primary psychotic disorders. In the authors' experience, low doses of antipsychotic medications do not significantly increase clinical risk of seizures in PWE being concurrently treated with an efficacious antiepileptic regimen.

Do antipsychotic drugs increase seizure frequency in epilepsy patients?

To investigate whether addition of antipsychotic drugs (APD) would increase seizure frequency in epilepsy patients who were already treated with anti-epileptic drugs (AED), we compared a one-year seizure control outcome in 150 epilepsy patients with APD treatment for psychiatric conditions and 309 epilepsy patients without APD treatment matched for ages at epilepsy onset and the baseline evaluation and types of epilepsy. The seizure frequency was recorded at the baseline (immediately before the start of APD) and after the 1st, 3rd, 6th and 12th months. The seizure outcome at each of the four follow-up points was compared with the baseline. The seizure outcome was compared between the two groups as a whole and according to the types of epilepsy (idiopathic generalized and partial epilepsies). In the APD group, the seizure outcome was also analyzed according to the types of APD (first and second generation APD and combination of first and second generation APD) and the types of psychiatric conditions (psychosis and non-psychosis). The seizure outcome was significantly better in the APD group than control group at all the four follow-up points. According to the epilepsy types, the improvement in the seizure outcome was only observed in the patients with partial epilepsy. Of the APD group, there was no significant difference in the seizure outcome according to the types of APD or the psychiatric conditions. In epilepsy patients who are already treated with AED, APD treatment seems safe in seizure control outcome for treatment of psychiatric conditions.