Smoking affects the association between cognitive impairment and P50 inhibition defects in patients with chronic schizophrenia: A case-control study.

OBJECTIVE: Smoking affects sensory gating, as assessed by the event related potential P50, which is evoked by auditory stimuli and is considered to be involved in the pathophysiology of schizophrenia (SCZ). However, few studies have compared sensory gating and cognitive performance between smoking and non-smoking SCZ patients in the Chinese Han population. METHODS: We recruited two groups of Chinese subjects: 128 male chronic SCZ patients and 76 male healthy controls, measuring cognition with the MATRICS Consensus Cognitive Battery (MCCB) and sensory gating with the P50 EEG components. Based on their smoking status, they were further divided into 4 subgroups: smoking SCZ patients, non-smoking SCZ patients, smoking healthy controls, and non-smoking healthy controls. We assessed psychopathological symptoms of the patients using the Positive and Negative Syndrome Scale (PANSS). RESULTS: Compared with healthy controls, SCZ patients had lower MCCB total score and scores of all 10 tests (all p < 0.05), while SCZ patients had higher S2 amplitudes and P50 ratios (both p < 0.05). When comparing smoking versus non-smoking SCZ patients, non-smokers had significantly better spatial span (p < 0.05). Furthermore, the S1 amplitude was negatively correlated with the Brief Visuospatial Memory Test (BVMT-R) in smoking patients (p < 0.05), while the S1 latency was negatively correlated with spatial span in non-smoking patients (p < 0.01). CONCLUSIONS: Our finding shows a difference in the relationship between sensory gated P50 and cognition in smoking and non-smoking SCZ patients, suggesting that nicotine may improve cognitive and P50 deficits in SCZ patients.

Demographics, clinical characteristics and cognitive symptoms of heavy smokers and non-heavy smokers in Chinese male patients with chronic schizophrenia.

Many studies have shown a high smoking rate and cognitive impairment in patients with schizophrenia. The effects of smoking and nicotine intake on cognitive function in schizophrenia are still controversial. In this study, we divided patients into heavy smoking and non-heavy smoking groups and compared the clinical characteristics and cognitive symptoms between the two groups in Chinese male patients with schizophrenia. A total of 154 heavy smoking patients and 372 non-heavy smoking patients were recruited. They completed a detailed questionnaire including general and socio-demographic data. Positive and Negative Syndrome Scale (PANSS) was rated for psychopathology. The Fagerstrom Test for Nicotine Dependence (FTND) was used to assess the degree of nicotine dependence. Heavy smokers were younger, started smoking earlier and had a higher FTND total score than non-heavy smoking patients. Moreover, we found that heavy smokers had significantly lower negative symptom scores and cognitive factor scores than non-heavy smokers. Logistic regression analysis showed that cognitive factor score and age of initial smoking were significantly associated with heavy smoking. Linear regression analysis showed that cognitive factor score, age of initial smoking and dose of antipsychotics were significant predictors of the amount of smoking. Our findings suggest that there are significant differences in some demographic and clinical variables between heavy and non-heavy smokers in Chinese male patients with chronic schizophrenia. Moreover, heavy smokers have less cognitive symptoms, suggesting that heavy smoking may be beneficial for cognition of patients with schizophrenia.

Alcohol use history increases the likelihood of suicide behavior among male chronic patients with schizophrenia in a Chinese population.

AIMS: This study was designed to detect the association between the history of alcohol drinking and suicidality in schizophrenia (SCZ) inpatients in a Chinese population. METHODS: We recruited 616 male SCZ inpatients and collected demographic and clinical data. Five-factor model of the Positive and Negative Syndrome Scale (PANSS) was used to assess their psychopathological symptoms. RESULTS: Our results showed that 31.33% of SCZ patients had a history of alcohol drinking. They had higher rates of lifetime suicide attempt and suicidal ideation than those without a history of alcohol drinking. Moreover, patients with a history of drinking were more likely to attempt suicide (14.51% vs. 7.09%; χ2  = 7.70, df = 1, p = 0.006), with an odds ratio (OR) of 2.22 and have suicidal ideation (29.02% vs. 17.49%; χ2  = 9.89, df = 1, p = 0.002), with an OR of 1.93. In addition, patients who used to drink alcohol were more likely to be smokers and had more severe positive and depressive symptoms (all p < 0.05). CONCLUSIONS: Our study indicates that history of alcohol drinking may increase the prevalence of lifetime suicide attempt and suicidal ideation in male patients with chronic SCZ. Moreover, the history of alcohol drinking may be associated with some demographic data and clinical symptoms.

Sex differences in P50 inhibition defects with psychopathology and cognition in patients with first-episode schizophrenia.

BACKGROUND: A large number of studies have shown that the pathophysiology of schizophrenia may be involved in sensory gating that appears to be P50 inhibition. However, few studies have investigated the relationship between clinical symptoms, cognitive impairment and sensory gating disorders in patients with first-episode schizophrenia. The purpose of this study was to explore the sex differences in the relationship between clinical symptoms, cognitive impairment and P50 inhibition defects in patients with first-episode schizophrenia, which has not been reported. METHODS: 130 patients with first-episode schizophrenia (53 males and 77 females) and 189 healthy controls (87 males and 102 females) participated in the study. Positive and Negative Syndrome Scale (PANSS) was used to evaluate the patients' psychopathological symptoms, and the 64-channel electroencephalogram (EEG) system was used to record the P50 inhibition. RESULTS: Male patients had higher PANSS negative symptom, general psychopathology, cognitive factor and total scores than female patients (all p < 0.01). The S1 amplitude was smaller in male than female patients (all p < 0.05). Multiple regression analysis showed that in male patients, S1 latency was contributor to negative symptoms, while S1 latency, S2 latency, age, and smoking status were contributors to cognitive factor (all p < 0.05). In female patients, no P50 component was found to be an independent contributor to PANSS scores (all p > 0.05). CONCLUSIONS: Our results indicate that there is a sex difference in the relationship between clinical symptoms, cognitive impairment and P50 inhibition defects in Chinese Han patients with first-episode schizophrenia.

Suicide attempts in Chinese Han patients with schizophrenia: cognitive, demographic, and clinical variables

Objective: The purpose of this study was to investigate the lifetime suicide attempt rate, clinical characteristics and cognitive function of Chinese patients with chronic schizophrenia who had attempted suicide. Methods: We collected data from 908 schizophrenia inpatients about suicide attempts through interviews with the patients and their families, as well as through medical records. All patients were assessed with the Positive and Negative Syndrome Scale, the Rating Scale for Extrapyramidal Side Effects, the Abnormal Involuntary Movement Scale, and the Repeated Battery for the Assessment of Neuropsychological Status. Results: Of this sample, 97 (10.68%) had attempted suicide. Patients who had attempted suicide were younger, had longer illness duration, and more severe general psychopathology and depressive symptoms than those who had not. Logistic regression analysis confirmed that suicide attempts were correlated with age, smoking, and depression. No cognitive performance differences were observed between patients who had and had not attempted suicide. Conclusions: In China, patients with chronic schizophrenia may have a higher prevalence of lifetime suicide attempts than the general population. Some demographic and clinical variables were related to suicide attempts in patients with chronic schizophrenia.

P50 inhibition defects with psychopathology and cognitive impairment in patients with first-episode drug naïve schizophrenia.

BACKGROUND: Many studies have announced that P50 inhibition defects represent sensory gating deficits in schizophrenia, but studies seldom have searched the correlation between P50 inhibition defects and the psychopathology or cognitive impairment of patients with first-episode, drug naïve (FEDN) of schizophrenia. In this study, we investigated the auditory sensory gating deficits in a large number of Han patients with FEDN schizophrenia and their correlation with clinical symptoms and cognitive impairment. METHODS: A total of 130 patients with FEDN schizophrenia and 189 healthy controls were recruited in this study. Positive and Negative Syndrome Scale (PANSS) and its five-factor model were used to score the psychopathology of the patients, and P50 inhibition was recorded using the 64-channel electroencephalography (EEG) system. RESULTS: Patients exhibited significantly longer S1 and S2 latency, lower S1 and S2 amplitudes and lower P50 difference than healthy controls (all p < 0.05). Significant correlations existed between S1 latency and PANSS negative symptoms or cognitive factor, P50 ratio and general psychopathology, P50 ratio and PANSS total score, P50 difference and general psychopathology, and P50 difference and PANSS total score (all p < 0.05). Multiple regression analysis revealed that S1 latency, sex, age, and education were contributors to negative symptom score (all p < 0.05). S1 latency, S2 latency, sex, age, and smoking status were contributors to cognitive factor (all p < 0.05). CONCLUSIONS: Our results show that patients with FEDN schizophrenia have P50 inhibition defects, which may be related to their psychopathological symptoms and cognitive impairment.

Prevalence of obesity and clinical and metabolic correlates in first-episode schizophrenia relative to healthy controls.

OBJECTIVE: People with schizophrenia exhibit a high obesity rate. However, little is known about the prevalence of obesity and its relationship with clinical symptoms and metabolic indicators in first-episode drug-naïve (FEDN) schizophrenia. METHODS: Demographic and lipid parameters were gathered from 297 FEDN schizophrenia and 325 healthy controls. The patients' symptomatology was evaluated by the Positive and Negative Syndrome Scale (PANSS). RESULTS: The obesity rate of FEDN patients was 10.77%, similar to that of controls (10.5%). The prevalence of overweight plus obesity of patients was 44.8%, significantly higher than that of controls (36.6%). Compared with non-obese patients, obese patients had higher levels of cholesterol (4.81 ± 0.93 vs 4.22 ± 1.00 mmol/L), triglyceride (0.27 ± 0.21 vs 0.14 ± 0.24 mg/dL), low-density lipoprotein (0.48 ± 0.12 vs 0.40 ± 0.12 mg/dL), greater ratio of triglyceride/high-density lipoprotein (2.01 ± 1.23 vs 1.44 ± 1.26), and higher PANSS positive symptom subscale score (29.81 ± 6.29 vs 27.05 ± 6.15), general psychopathology subscale score (70.75 ± 11.74 vs 66.87 ± 11.37), and total score (149.81 ± 21.08 vs 140.64 ± 21.58), but lower high-density lipoprotein level (1.09 ± 0.21 vs 1.27 ± 0.34 mg/dL) (all p < 0.05). Correlation analysis revealed that body mass index (BMI) was positively correlated with triglyceride, cholesterol, high-density lipoprotein, low-density lipoprotein, triglyceride/high-density lipoprotein ratio, PANSS positive symptoms, general psychopathology, and total scores (all p < 0.05, r = 0.124 ~ 0.335). Multiple regression analysis confirmed that PANSS positive symptoms, total score, and cholesterol level were significantly associated with BMI (all p < 0.05, ß: 0.126-0.162). CONCLUSION: There was no significant difference in the prevalence of obesity between FEDN patients and the control group. Moreover, BMI was positively associated with positive symptom severity in FEDN patients.

Association of cigarette smoking with cognitive impairment in male patients with chronic schizophrenia.

BACKGROUND: Previous studies have shown that patients with schizophrenia have higher smoking rates and worse cognitive function than healthy controls. However, there is no consistent conclusion about the relationship between smoking and cognitive impairment. OBJECTIVES: The main purpose of this study was to explore the effects of smoking on cognitive function by using MATRICS Cognitive Consensus Battery (MCCB) in Chinese male patients with schizophrenia. METHODS: There were 164 patients with chronic schizophrenia and 82 healthy controls. All subjects were interviewed about smoking status. The cognitive function was assessed by MCCB and Stroop tests. The Positive and Negative Syndrome Scale (PANSS) was used to assess the clinical symptoms of the patients. RESULTS: Compared with healthy controls, patients had lower MCCB scores in all of its domain scores (all p < 0.05). In the patients, the scores of spatial span test (42.3 ± 11.6), digital sequence test (42.9 ± 10.6), and Hopkins Verbal Learning Test (42.2 ± 10.1) were lower in smokers than those in nonsmokers (all p < 0.05, effect size: 0.28-0.45). Logistic regression analysis showed that the smoking status of the patients was correlated with digital sequence score (p < 0.05, OR = 1.072, 95%CI: 1.013-1.134). Multivariate regression analysis showed that the spatial span total score (ß = - 0.26, t = - 2.74, p < 0.001) was associated with the duration of smoking in patients with schizophrenia. CONCLUSIONS: Our findings show that smoking patients with chronic schizophrenia exhibit more severe cognitive impairment than nonsmoking patients, especially in working memory and executive function.

Suicide attempts in Chinese Han patients with schizophrenia: cognitive, demographic, and clinical variables.

OBJECTIVE: The purpose of this study was to investigate the lifetime suicide attempt rate, clinical characteristics and cognitive function of Chinese patients with chronic schizophrenia who had attempted suicide. METHODS: We collected data from 908 schizophrenia inpatients about suicide attempts through interviews with the patients and their families, as well as through medical records. All patients were assessed with the Positive and Negative Syndrome Scale, the Rating Scale for Extrapyramidal Side Effects, the Abnormal Involuntary Movement Scale, and the Repeated Battery for the Assessment of Neuropsychological Status. RESULTS: Of this sample, 97 (10.68%) had attempted suicide. Patients who had attempted suicide were younger, had longer illness duration, and more severe general psychopathology and depressive symptoms than those who had not. Logistic regression analysis confirmed that suicide attempts were correlated with age, smoking, and depression. No cognitive performance differences were observed between patients who had and had not attempted suicide. CONCLUSIONS: In China, patients with chronic schizophrenia may have a higher prevalence of lifetime suicide attempts than the general population. Some demographic and clinical variables were related to suicide attempts in patients with chronic schizophrenia.

One-day tropisetron treatment improves cognitive deficits and P50 inhibition deficits in schizophrenia.

The core features of schizophrenia (SCZ) include cognitive deficits and impaired sensory gating represented by P50 inhibition deficits, which appear to be related to the α7 nicotinic acetylcholine receptor (nAChR). An agonist of nAChR receptor may improve these defects. This study aimed to investigate how administering multiple doses of tropisetron, a partial agonist of nAChR, for 1 day would affect cognitive deficits and P50 inhibition deficits in SCZ patients. We randomized 40 SCZ non-smokers into a double-blind clinical trial with four groups: placebo, 5 mg/d, 10 mg/d, and 20 mg/d of oral tropisetron. Their P50 ratios were all more than 0.5 and they took risperidone at 3-6 mg/day for at least a month before participating in the experiment. We measured the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and P50 inhibition before and one day after treatment. After one day of treatment, the total RBANS scores of the 20 mg and 5 mg tropisetron groups, and the immediate memory of the 10 mg group were significantly higher than placebo group. The P50 ratio was smaller in the 5 mg and 10 mg groups than in the placebo group (both p < 0.05) after treatment. Furthermore, the improvement in RBANS total score was correlated with increased S1 latency (p < 0.05), and the increase in immediate memory score was correlated with decreased S2 amplitude. One day of treatment with tropisetron improved both cognitive and P50 inhibition deficits, suggesting that longer term treatment with α7 nAChR agonists for these deficits in SCZ may be promising.

Association of cognitive and P50 suppression deficits in chronic patients with schizophrenia.

OBJECTIVE: Cognitive deficits are core symptoms of schizophrenia; however, their pathophysiological mechanisms are still unclear. A sensory gating deficit, as reflected by P50 suppression, has been repeatedly shown in schizophrenia patients, which may be associated with cognitive deficits in this disorder. The present study was to examine the relationship between the P50 suppression and cognitive deficits in patients with schizophrenia, which is still under-investigated. METHOD: We recruited 38 chronic schizophrenia patients and 32 matched healthy controls, and assessed their cognition with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and P50 suppression with the electroencephalography system. RESULTS: The total and its 4 index scores (all p < 0.05) except for the visuospatial/ constructional index of RBANS were significantly lower in patients compared with healthy controls. However, only the language and attention passed Bonferroni corrections. Patients displayed a significantly higher P50 ratio, higher S2 amplitude, and lower S1 amplitude (all p < 0.05) than healthy controls. Interestingly, only in the patients, the S1 amplitude was associated with both language and attention, and the S2 amplitude with both visuospatial/ constructional and language (all p < 0.05), although all of these significances did not pass the Bonferroni corrections. The P50 ratio was not associated with any of the RBANS scores (all p > 0.05). CONCLUSIONS: Our results suggest the P50 suppression deficits in Chinese patients with schizophrenia, which may be associated with cognitive impairments of this illness. Moreover, the amplitude of S1 and the amplitude of S2 may be involved in the different cognitive domain deficits in schizophrenia patients. SIGNIFICANCE: This study suggests that the P50 components may possibly be effective biomarkers for cognitive deficits in patients with schizophrenia.

Obesity in Chinese patients with chronic schizophrenia: Prevalence, clinical correlates and relationship with cognitive deficits.

The prevalence of obesity in schizophrenia patients is high, especially in chronic and medicated patients. Few studies have explored the relationships between obesity, cognition and clinical correlates in patients with schizophrenia. This study was designed to assess the prevalence and clinical correlates of obesity and its relationship to cognitive impairment in Chinese patients with schizophrenia. We recruited 633 inpatients and collected clinical, demographic data and lipid parameters. The Positive and Negative Syndrome Scale (PANSS) and its five-factor model were adopted for psychopathological symptoms. The prevalence of comorbid obesity in schizophrenia patients was 16.4%. The plasma levels of glucose, triglyceride, low density lipoprotein (LDL), apolipoprotein B, and cholesterol were higher, but high density lipoprotein (HDL) levels were lower in obese patients than those in non-obese patients (all p < 0.05). Furthermore, obese patients had lower PANSS negative symptom, cognitive factor and total scores than non-obese patients (all p < 0.05). Correlation analysis showed a significant correlation between BMI and the following variables: age, marriage, gender, negative symptoms, general psychopathological symptoms, cognitive factor, PANSS total score, glucose, triglycerides, HDL, LDL, cholesterol and apolipoprotein B (all p < 0.05). Further multiple regression showed that PANSS cognitive factor, PANSS total score, and triglyceride were important independent predictors of obesity. Our results indicate a high prevalence of obesity in Chinese patients with chronic schizophrenia. Multiple demographics, clinical variables, and lipid parameters are associated with obesity in schizophrenia. Moreover, obesity appears to be a protective factor for psychological symptoms. However, not having objective assessments for cognition in this study is a limitation.

P50 inhibition deficit in patients with chronic schizophrenia: Relationship with cognitive impairment of MATRICS consensus cognitive battery.

OBJECTIVE: Cognitive impairment is a core symptom of schizophrenia (SCZ); however, its pathophysiological mechanisms remain unclear. The sensory gating (SG) deficits reflected by P50 inhibition are recurring in SCZ, and this inhibition may be related to the cognitive deficits seen in these individuals. This study aimed to investigate the relationship between P50 inhibition and cognitive dysfunction in SCZ, which has not been fully investigated up to this point. METHODS: A total of 270 individuals with chronic SCZ and 116 healthy controls were enrolled in the study. Psychopathology of SCZ was rated by the positive and negative syndrome scale (PANSS), while cognitive function and P50 inhibition of subjects were assessed by the MATRICS Consensus Cognitive Battery (MCCB) and the electroencephalography system. RESULTS: The MCCB total and its 10 index scores were significantly lower in patients than those in healthy controls (all p < 0.001). SCZ patients had a lower amplitude of S1, and higher P50 ratio than healthy controls (both p < 0.01). However, there were no significant correlations between the P50 ratio and any of the PANSS total and its subscale scores in SCZ patients (all p > 0.05). Moreover, no correlation was found between the P50 components and the MCCB scores (all p > 0.05). CONCLUSIONS: Our findings suggest that the P50 inhibition deficits occur in Chinese individuals with SCZ, which may not be associated with their clinical symptoms and cognitive impairment.