BACKGROUND: Schizophrenia affects 7 people per 1000 adult population worldwide and is a severe form of mental illness common in age group 15-35 year old. Paliperidone is the active metabolite of risperidone and was approved for treatment of schizophrenia in the Philippines by the Food and Drug Administration (FDA) in 2007. The drug has been shown to be safe and effective in clinical trials but no local study has investigated its effect among Filipino patients. Hence, the general objective of this study was to assess the safety and effectiveness of paliperidone ER among Filipino patients diagnosed with schizophrenia.

METHODS: The study was a non-randomized, non-comparative, open-label trial involving adult patients seen at initial consult and at the end of study visit. Study duration was eight weeks and was conducted for three years as required by the FDA. The primary outcome for the study was overall severity of the illness at the initial visit and end visit (visit 2) using the Clinical Global Impression tool (CGI-S). This rating scale was used to rate the severity of a subject's pyschotic condition on a 7-point scale ranging from 1 (not ill) to 7 (extremely severe).

RESULTS: A total of 641 Filipino adults were enrolled in the study. Ninety one percent (N=586) had completed the follow-up into the second or end visit resulting in a 9% drop out for the duration of the study. Follow-up period had an average of 58.05 (SD+=9.36) days ranging from a minimum of 4 to a maximum of 98 days. Clinicians' assessment of the severity of illness showed that majority had shown improvement from their baseline clinical state with the use of Paliperidone ER. The proportion of severely ill had decreased by 15% while the proportion of those who were markedly ill had decreased by 15% while the proportion of those who where markedly ill had decreased by 35% by the end of the second visit. Overall, after eight weeks of paliperidone treatment, there was a decrease of 58% in the proportion of subjects evaluated to be mildly ill, borderline mentally ill and normal at the end of the second visit. This means that there was a marked improvement in patients observed and reported symptoms, behavior and functions as assessed by physicians using CGI. Fifteen percent of study participants experienced at least one non-serious adverse event during the study. The five most common non-serious adverse events observed include sleeplessness, extrapyramidal symptoms described as Pseudo parkinsonian tremors, stiffness of body and DOB/EPS reaction hand tremors, depression, akathisia and dizziness.

CONCLUSION: Paliperidone ER administered at 6 mg single dose improved symtoms and clinical signs among adult Filipinos diagnosed with schizophrenia who are moderately and markedly ill. The drug is will-tolerated, but the dose may need to be increased for more severely ill patients. Paliperidone ER is one of the current useful options for the treatment of patients with schizophrenia.