Effect of aripiprazole and olanzapine on the cognitive function in patients with schizophrenia

Xiao-Hong Wang

Shalingzi Hospital of Zhangjiakou City, Zhangjiakou, Hebei, 075100

Keywords:Schizophrenia Aripiprazole Olanzapine Cognitive function

ABSTRACT Objective: To observe the effect of aripiprazole and olanzapine on the cognitive function in patients with schizophrenia in order to provide a reference evidence for the clinical medication. Methods: A total of 60 patients with schizophrenia who were admitted in our hospital were included in the study and randomized into the treatment 1 group and treatment 2 group. The patients in the two groups were given aripiprazole and olanzapine, respectively. PANSS, WCST, DS, IGT, and EIRT were used to evaluate the disease condition and cognitive function before and after treatment in the two groups. Results: Comparision of PANSS scores and other various scores before treatment between the two groups was not significantly different (P＞0.05); however, PANSS scores and other various scores after treatment were significantly reduced (P＜0.05). Comparision of PANSS scores and other various scores after treatment between the two groups was not significantly different (P＞0.05). DS, WCST, and IGT scores before treatment between the two groups was comparable (P＞0.05), and those scores after treatment were significantly elevated (P＜0.05). DS score after treatment in the treatment 2 group was significantly higher than that in the treatment 1 group (P＜0.05). Comparison of WCST and IGT scores after treatment between the two groups was not significantly different (P＞0.05). The four cognition scores of happiness, fear, anger, and disgust after treatment in the treatment 1 group were significantly elevated (P＜0.05), while the cognition of happiness and sadness after treatment in the treatment 2 group was significantly elevated when compared with before treatment (P＜0.05). The comparison of various scores before and after treatment between the two groups was not significantly different (P＞0.05). Conclusions: Aripiprazole and olanzapine can improve the clinical symptoms and partial cognitive function in patients with schizophrenia, while aripiprazole can make a better effect on the work and memory.

1. Introduction

The schizophrenia is frequently occurred in the late adolescence and early adulthood with unknown pathogenesis and abnormal mental activities of cognition, thinking, emotion, and behavior after onset, which can severely damage the occupation and social functions [1, 2]. According to WHO statistics [3], the global prevalence rate of schizophrenia is 0.53% and the life-long morbidity is 0.66%. The schizophrenia can not only affect the whole social function, but also can cause negative effects on the family and society [4]. Currently, the drugs are mainly adopted for the treatment of schizophrenia with psychotherapy as the assistance. After treatment, the clinical symptoms in most patients can obviously improved, but the promotion of social function is not good, which is probably associated with the long social function damage [5-8]. It is argued that [9, 10] improvement for the social function during the treatment process for patients with schizophrenia has a positive significance for enhancing the social function after treatment. On the above basis, the study is aimed to observe the effect of aripiprazole and olanzapine on the cognitive function in patients with schizophrenia in order to provide a reference evidence for the clinical medication.

2. Materials and methods

2.1. Clinical materials

A total of 60 patients with schizophrenia who were admitted in our hospital from January, 2019 to June, 2019 were included in the study, with 24 male and 36 female; aged from 18 to 65 years with an average of (34.7±9.1) years; education degree greater than 6 years with an average of (10.9±3.5) years; 22 married and 48 unmarried. Inclusion criteria: (1) those who were in accordance with the related diagnostic criteria of The Diagnostic and Statistical Manual of Mental Disorders (US, The Fifth Edition) [11]; (2) those who had not taken the antipsychotic drugs recently; (3) those who had not received the electric shock treatment within half a year. Those who had a history of vision and hearing disorder, cerebral organic disease, severe somatic disease, brain injury, and psychoactive drug substance dependence were excluded from the study. Before treatment, an explanation for the effectiveness of the two studied drugs was made for the patients and their relatives, and then the informed consents were signed.

2.2. Methods

The included patients were randomized into the treatment 1 and 2 groups, with 30 cases in each group. The gender, age, education degree, and marital status between the two groups were comparable (P＞0.05). The patients in the treatment 1 group were orally administrated with olanzapine (Ou Lanning, produced by Jiangsu Hanson Pharmaceutical Limited Company, Approval No. H20052688, Specification: 5mg/tablet), while the patients in the treatment 2 group were given aripiprazole (Bo Siqing, produced by Chendu Kanghong Pharmaceutical Limited Company, Approval No. H200605021, Specification: 5mh/tablet). The patients in the two groups were continuously treated for 6 weeks. The recommended minimum dose was used for the patients in the two group in the initial, while it was increased to the treatment dose within 1 week. During the treatment process, no other antipsychotic drugs were used. The average dose in the treatment 1 group was (18.5±2.6) mg, while the average dose in the treatment 2 group was (25.2±4.3) mg. During the treatment process, if adverse reactions or sleep disorders occurred, the drug dose or time would be adjusted according to the patients’ specific conditions.

2.3. Observation indicators

PANSS, WCST, DS, IGT, and EIRT were used to estimate the disease condition degree and cognition function before and after treatment.

2.4. Statistical analysis

SPSS 20.0 software was used for the statistical analysis. ANOVA, Chi-square test, and t test were used for the comparison of the multiple independent samples. P＜0.05 was regarded as statistically significant.

3. Results

3.1. Comparison of PANSS score before and after treatment

Comparison of the total PANSS score and various scores before treatment between the two groups was not statistically significant (P＞0.05). The total PANSS score and various scores after treatmentwere significantly reduced (P＜0.05). Comparison of the total PANSS score and various scores after treatment between the two groups was not statistically significant (P＞0.05) (Table 1).

Table 1 Comparison of PANSS score before and after treatment (score)

Table 2 Comparison of the cognition function before and after treatment

Table 3 Comparison of EIRT score before and after treatment

3.2. Comparison of the cognition function before and after treatment

DS, WCST, and IGT scores before treatment between the two groups were comparable (P＞0.05), while those scores were significantly elevated after treatment (P＜0.05). DS score after treatment in the treatment 2 group was significantly higher than that in the treatment 2 group (P＜0.05), but the comparison of WCST and IGT scores between the two groups was not statistically significant (P＞0.05) (Table 2).

3.3. Comparison of EIRT score before and after treatment

The four cognition scores of happiness, fear, anger, and disgust after treatment in the treatment 1 group were significantly elevated (P＜0.05), while the cognition of happiness and sadness after treatment in the treatment 2 group was significantly elevated when compared with before treatment (P＜0.05). The comparison of various scores before and after treatment between the two groups was not significantly different (P＞0.05) (Table 3).

4. Discussion

It has been clinically acknowledged that there is a cognition function damage in the schizophrene patients, whose function damage degree is 1.5-2.0 SD higher than that in the healthy individuals [12-17]. It is deemed that the cognition function damage is probably the inherent part of the disease itself in patients with schizophrene and has no relation with the chronicity of the disease and the long-term medication [18]. Some scholars argue that the cognition function damage is one of the core symptoms of schizophrene, and is closely associated with the function prognosis [19]; therefore, how to improve the cognition function during the treatment process has been a topic issue.

The traditional antipsychotic drugs has a significant effect in improving the positive clinical symptoms in patients with schizophrene, but it can also induce the side effect of extrapyramidal system, which can affect some advanced cognition process [20]. In addition, application of anticholinergic drugs can further aggravate the cognitive function damage; therefore, the traditional therapeutic drugs are not recommended as the first-line treatment drugs [21]. With the acceleration of new drug development, the new-type antipsychotic drugs, such as olanzapine, aripiprazole, clozapine, risperidone, etc, are constantly available, and those drugs have a double antagonistic action on DAD2 and 5-HT2a with a significant therapeutic effect and have a potentially beneficial effect on the cognitive function [22]. Olanzapine and aripiprazole are two common atypical antipsychotic drugs in the clinic with different action mechanism. The study is aimed to observe the differnece of cognitive function before and after treatment in patients with schizophrenia treated by these two new-type antipsychotic drugs in order to provide an evidence for the rational selection. Olanzapine has a strong antagonistic actin on DAD2 and 5-HT2a, with a weak effect on DA [23]. Aripiprazole has an antagonistic action on 5-HT2a, has partial agnoistic action on DAD2 and 5-HT1A, and can enhance DA function due to the frontal insufficiency so as to improve the negative symptoms [24]. The results in the study showed that the toal scores and other various scores of PANSS after treatment in the treatment 1 and 2 groups were significantly improved when compared with before treatment (P＜0.05), but the comparison among the groups was not significantly different (P＞0.05), proving that these two drugs can effectively improve the mental symptoms in patients with schizophrenia with an equal efficacy, which is consistent with the results reported by Li et al [25]. The comparison of DS, WCST, and IGT scores before treatment between the two groups was comparable (P＞0.05), and DS, WCST, and IGT scores after treatment were significantly elevated when compared with before treatment (P＜0.05), indicating that these two drugs have a certain improving effect on the cognitive function in patients with schizophrenia. However, DS score after treatment in the treatment 2 group was significantly higher than that in treatment 1 group (P＜0.05), showing that aripiprazole has a more significant effect in improving the working memory, with a certain treatment advantage. In conclusion, aripiprazole and olanzapine can improve the clinical symptoms and partial cognitive function in patients with schizophrenia, while aripiprazole can make a better effect on the work and memory.