Schizophrenia is a chronic and severe psychiatric disorder, these patients suffer from positive symptoms, negative symptoms and cognitive deficits, of which working memory problems are considered a central cognitive impairment. Atypical antipsychotics are believed to have a superior effect in reducing both positive and negative symptoms of schizophrenia, coupled with a low risk of extrapyramidal symptoms. Particularly, 2nd-generation antipsychotic medications are commonly used in treatment of schizophrenia. An antipsychotic drug, Paliperidone palmitate (PDP), is administered to patients with schizophrenia as injections at one-month (PP1M) or three-month (PP3M) intervals. This study was compare the effects of treatment, social function, and side effects between PP1M and PP3M in patients with schizophrenia. Moreover, the changes of cognitive and lipid profile between two PDP were also explored. Firstly, participants were received the one month long-acting injection (PP1M) three months. Then, the stable participants were shifted to the three month long-acting injection (PP3M). Concomitant medications were allowed to prescribe except other antipsychotics. Outcome measurements were 20-item Toronto Alexithymia Scale (TAS-20), 45-itme quality of life for mental disorder (QOLMD), Short-version of the Udvalg for Kliniske Undersogelser (short-version UKU), and Wisconsin Card Sorting test (WCST). These measurements were performed every three-month except WCST which was performed every six-month. The different effects of PP1M and PP3M will be expected to find out in this study.

This is a two and half-one years, single-arm, nonrandomized, open-label study which was conducted between Jan 2015 to Jun 2017 including from a psychiatric center in southern Taiwan. The stable schizophrenic patients who previously received risperidone long-acting injection for more than one year and shifted to paliperidone palmitate after including in the study. Firstly, participants were received the one month long-acting injection (PP1M) three months. Then, the stable participants were shifted to the three month long-acting injection (PP3M). Concomitant medications were allowed to prescribe except other antipsychotics. Outcome measurements were 20-item Toronto Alexithymia Scale (TAS-20), 45-itme quality of life for mental disorder (QOLMD), Short-version of the Udvalg for Kliniske Undersogelser (short-version UKU), and Wisconsin Card Sorting test (WCST). These measurements were performed every three-month except WCST which was performed every six-month. The effect of treatment was assessed using Personal and Social Performance (PSP) scales for the evaluation of psychosocial functioning at 0, 4, 8, and 12 weeks in first study, and at 0, 3, 6, 9, 12 months in second study, respectively. In addition, all participants were assessed for body weight, waist circumference, and blood lipid profile. To evaluate the lipid profiles, fasting blood samples were analyzed for total cholesterol (TC), Triglyceride (TG), High-density Lipoprotein (HDL) and Low-density Lipoprotein (LDL). These blood samples were collected at every month until study completion.

Inclusion Criteria:

• All of them had to meet the diagnostic criteria for schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).

Exclusion Criteria:

• Patients who had comorbid serious medical illnesses, and may therefore present substantial clinical risk due to pharmacotherapy, were excluded from the sample, as were pregnant and lactating women.