Objective The aim of this research study was:
To identify the risk factors for Post-Ictal Psychosis (PIP)
To describe the phenomenology of PIP and how it compares with Schizophrenia.
Method The study design is a case control study comprising 22 subjects with a diagnosis of Epilepsy and PIP (cases) and 44 subjects with Epilepsy (controls). The setting of the project is a tertiary centre neurology outpatient clinic. Demographic and clinical characteristics including risk factors were reviewed retrospectively and compared across both the groups. Categorical data were analysed using Chi-Square analysis while quantitative data were analysed using Wilcoxon Signed Rank and Mann–Whitney U tests.
Results Post-Ictal Psychosis (PIP) followed a cluster of seizures with a mean frequency of 2.19 in the cases (PIP) group and this was statistically significant when compared to that in the week prior to last clinic in the control group (z=3.874, N-Ties=19, p=0.000). The mean duration of epilepsy prior to onset of PIP was 18.82 years (N=22, Std. Dev.=11.742). Family history of psychiatric illness was similar in both the groups (χ2=0.000, df=1, p=1.000). There was a tendency towards association of focal epilepsy to PIP compared to the control group (df=1, p=0.143). Looking at the phenomenology of PIP, the duration of psychotic episode ranged from 12 hours to 2 weeks and the clinical features comprised mainly of auditory and visual hallucinations, religious and grandiose delusions and significant violent behaviour.
Conclusion The author's study echoes previous studies' findings in areas of increased seizure frequency and chronicity of epilepsy prior to Post-Ictal Psychosis (PIP). However there is no association of family history of psychiatric illness to PIP and this along with the finding of a tendency towards an association of focal epilepsy to PIP suggests that epileptic factors play a more significant role than genetic factors in the emergence of PIP. Looking at the phenomenology of PIP, the duration of psychosis is of a transient and episodic nature. However symptoms of PIP are remarkable for its absence of 1st rank symptoms and negative symptoms which are characteristic of Schizophrenia. The other interesting aspect is the significance of religious delusions and violent behaviour both of which have been described as epileptic personality traits in the literature before.