The Role of Two Factors of Negative Symptoms and Cognition on Social Functioning in Male Patients with Schizophrenia: A Mediator Model

OBJECTIVE

This study aims to compare the cognitive function and social functioning in male patients with deficit syndrome (DS) and non-DS, and to explore whether cognitive function serves as a mediator in the relationship between the two factors of negative symptoms (motivation and pleasure (MAP) and expressivity (EXP) deficits, and social functioning in schizophrenia patients.

METHODS

One hundred and fifty-six male patients with schizophrenia and 109 age- and education-matched normal controls were enrolled in the current study. The Chinese version of a Schedule for Deficit Syndrome (SDS) was used for DS and non-DS categorization. The Brief Psychiatric Rating Scale (BPRS) and the Brief Negative Symptoms Scale (BNSS) were used to assess psychotic and negative symptoms in patients. The Social-Adaptive Functioning Evaluation (SAFE) was adopted to evaluate patients' social functioning, and a battery of classical neurocognitive tests was used to assess cognition, including sustained vigilance/attention, cognitive flexibility, ideation fluency, and visuospatial memory.

RESULTS

We found that male patients with DS performed worse in all four cognitive domains and social functioning compared to non-DS patients. Both total negative symptoms and its two factors were significantly associated with all four domains of cognition and social functioning in male patients. Interestingly, our results indicate that only cognitive flexibility mediates the relationship between negative symptoms and social functioning in schizophrenia patients, but there were no differences between EXP and MAP negative factors in this model.

CONCLUSION

Our findings suggest that DS patients may represent a unique clinical subgroup of schizophrenia, and the integrated interventions targeting both negative symptoms and cognition, especially cognitive flexibility, may optimally improve functional outcomes in schizophrenia patients.

Contrasting Frontoparietal Network Connectivity in Antipsychotic Medication-Naive First-Episode Psychosis Patients Who Do and Do Not Display Features of the Deficit Syndrome

BACKGROUND

The deficit syndrome is a clinical subtype of schizophrenia that is characterized by enduring negative symptoms. Several lines of evidence point to frontoparietal involvement, but the frontoparietal control network (FPCN) and its subsystems (FPCNA and FPCNB) proposed by Yeo et al. have not been systematically characterized at rest in patients with the deficit syndrome.

METHODS

We used resting-state fMRI to investigate the FPCN and its subnetworks in 72 healthy controls and 65 antipsychotic medication-naive, first-episode psychosis patients (22 displayed deficit syndrome features, 43 did not). To assess whole-brain FPCN connectivity, we used the right posterior parietal cortex as the seed region. We then performed region of interest analyses in FPCN subsystems.

RESULTS

We found that patterns of FPCN dysconnectivity to the whole brain differed in patients who displayed deficit syndrome features compared with those who did not. Examining the FPCN on a more granular level revealed reduced within-FPCN(A) connectivity only in patients displaying deficit features. FPCNB connectivity did not differ between patient groups.

DISCUSSION

Here, we describe a neurobiological signature of aberrant FPCN connectivity in antipsychotic-naive, first-episode patients who display clinical features of the deficit syndrome. Importantly, frontoparietal subnetwork connectivity differentiated subgroups, where the FPCNA is selectively involved in patients with deficit features. Our findings add to the growing body of literature supporting a neurobiological distinction between two clinical subtypes of schizophrenia, which has the potential to be leveraged for patient stratification in clinical trials and the development of novel treatments.

From Memories of Past Experiences to Present Motivation? A Meta-analysis on the Association Between Episodic Memory and Negative Symptoms in People With Psychosis

Based on findings from cognitive science, it has been theorized that the reductions in motivation and goal-directed behavior in people with psychosis could stem from impaired episodic memory. In the current meta-analysis, we investigated this putative functional link between episodic memory deficits and negative symptoms. We hypothesized that episodic memory deficits in psychosis would be related to negative symptoms in general but would be more strongly related to amotivation than to reduced expressivity. We included 103 eligible studies (13,622 participants) in the analyses. Results revealed significant, moderate negative associations of episodic memory with negative symptoms in general (k = 103; r = -.23; z = -13.40; P ≤ .001; 95% CI [-.26; -.20]), with amotivation (k = 16; r = -.18; z = -6.6; P ≤ .001; 95% CI [-.23; -.13]) and with reduced expressivity (k = 15; r = -.18; z = -3.30; P ≤.001; 95% CI[-.29; -.07]). These associations were not moderated by sociodemographic characteristics, positive symptoms, depression, antipsychotic medication or type of negative symptom scale. Although these findings provide sound evidence for the association between episodic memory deficits and amotivation, the rather small magnitude and the unspecific pattern of this relationship also indicate that episodic memory deficits are unlikely to be the only factor relevant to amotivation. This implicates that future research should investigate episodic memory in conjunction with other factors that could account for the association of episodic memory deficits and amotivation in psychosis.

Investigating the Relationship between White Matter Connectivity and Motivational Circuits in Subjects with Deficit Schizophrenia: A Diffusion Tensor Imaging (DTI) Study

Deficit schizophrenia is a subtype of schizophrenia presenting primary and enduring negative symptoms (NS). Although one of the most updated hypotheses indicates a relationship between NS and impaired motivation, only a few studies have investigated abnormalities of motivational circuits in subjects with deficit schizophrenia (DS). Our aim was to investigate structural connectivity within motivational circuits in DS. We analyzed diffusion tensor imaging (DTI) data from 46 subjects with schizophrenia (SCZ) and 35 healthy controls (HCs). SCZ were classified as DS (n = 9) and non-deficit (NDS) (n = 37) using the Schedule for Deficit Syndrome. The connectivity index (CI) and the Fractional Anisotropy (FA) of the connections between selected brain areas involved in motivational circuits were examined. DS, as compared with NDS and HCs, showed increased CI between the right amygdala and dorsal anterior insular cortex and increased FA of the pathway connecting the left nucleus accumbens with the posterior insular cortex. Our results support previous evidence of distinct neurobiological alterations underlying different clinical subtypes of schizophrenia. DS, as compared with NDS and HCs, may present an altered pruning process (consistent with the hyperconnectivity) in cerebral regions involved in updating the stimulus value to guide goal-directed behavior.

White Matter Neurometabolic Signatures Support the Deficit and Nondeficit Distinction in Antipsychotic-Naïve First-Episode Psychosis Patients

The deficit syndrome is thought to be a more homogenous clinical subgroup within the syndrome of schizophrenia that is characterized by enduring negative symptoms. It is hypothesized that distinct pathophysiological processes underlie the subtypes, where the deficit syndrome reflects an early onset nonprogressive developmental process, and the nondeficit form of the illness is characterized by attenuated neuroplasticity secondary to elevated glutamate levels. We used single-voxel magnetic resonance spectroscopy (PRESS; TE: 30 ms) to measure left frontal white matter neurometabolite levels in 61 antipsychotic-naïve first-episode psychosis patients (39 who did not display deficit features, 22 who did display deficit features, assessed with the Schedule for the Deficit Syndrome) and 59 healthy controls. Metabolite levels were quantified with the LCModel. We used a MANCOVA to determine neurometabolite differences between healthy controls, deficit syndrome patients, and nondeficit patients. We report a significant group difference when all metabolites were considered jointly (F[10,208] = 2.16; P = .02). Post hoc analyses showed that patients presenting without deficit features had higher glutamate levels than patients with deficit features and controls. Patients presenting without deficit features also had significantly higher myoinositol levels than controls; myoinositol levels were trend-level higher in patients presenting with deficit features compared to controls. Our data support the idea that the pathophysiology of patients presenting without deficit features may differ from those presenting with deficit features.

Current perspectives in treating negative symptoms of schizophrenia: A narrative review (Review)

The negative symptoms of schizophrenia are an unmet treatment target as currently approved treatments mostly control positive symptoms. The persistence of these symptoms holds back the patient's reinstatement in society, making them incapable of fulfilling their social, professional, or family roles. There is overwhelming research evidence suggesting that the negative symptoms of schizophrenia are associated with poorer functioning and lower quality of life than positive symptoms, confirming the need for developing new treatments for this particular category of symptoms. This present review aims to review clinical trials addressing novel pharmacological approaches addressing primary negative symptoms of schizophrenia. We overview both monotherapies, first-generation and second-generation antipsychotics, and add-on therapies, including psychostimulants, anti-inflammatory drugs, antidepressants, molecules targeting glutamatergic, cholinergic or serotonergic systems and hormones. Our findings suggest that the primary negative symptoms of schizophrenia may be mitigated by adjunctive therapies, and we highlight the pharmacological agents that have proven superior efficacy. Novel compounds such as cariprazine and MIN-101, to date, show promising results, but large clinical trials are needed to test their efficacy and safety.

Characterization of deficit schizophrenia and reliability of the bidimensional model of its negative symptomatology

Background: Cumulative evidence has demonstrated important differences between deficit (DS) and non-deficit (NDS) schizophrenia, suggesting that DS may be a separate disease. However, most data come from the same research groups and more replication is needed to validate this hypothesis.Aims: Our study aimed to examine the distribution of DS, to compare their characteristics with NDS patients and to analyze the reliability of the two-factor structure of its negative symptomatology in a Spanish clinical sample.Methods: Sixty clinically stabilized patients with schizophrenia were evaluated. The Schedule for the Deficit Syndrome was used for DS/NDS categorization. Patient characteristics included age, gender, education, age at onset of psychosis, duration of illness, family history of psychosis, type of antipsychotic regimen, schizophrenia subtype and severity of the disease.Results: DS prevalence was 28.3%. Bivariate analysis revealed statistical differences between DS and NDS in terms of years of education and schizophrenia subtype. Factor analysis replicated the two-factor solution consisting of the 'Expressive deficit' and 'Avolition-apathy' domains reported in previous studies.Conclusions: Our results were consistent with the published data and indicated that the DS profile in the Spanish population is similar to that in other populations, which would corroborate the homogeneity of DS within the schizophrenia spectrum and contribute to the hypothesis that DS constitutes a separate disease.

Recognition of Social Rule Violation in "Deficit Syndrome" Schizophrenia: A Study Using Economic Games

Aberrant social behavior is a frequent clinical feature of schizophrenia and seems related to the duration and chronicity of the disorder. However, there is a paucity of research into the relationship between social behavior and social cognition in patients with severe chronic courses of schizophrenia. Accordingly, the present study sought to examine the appreciation of social rules and norms such as fairness and cooperation in schizophrenia patients who fulfilled the criteria for "deficit syndrome". To this end, we utilized a so-called Ultimatum Game, and a Dictator Game, in which participants had the option to punish others' unfair behavior. In addition, "theory of mind", the ability to appreciate others' mental states, was also examined using the Mental State Attribution Task (MSAT). Symptom severity was determined using the Positive and Negative Syndrome Scale. While patients with deficit schizophrenia responded to varying levels of fairness in similar ways to controls, the patients accepted fewer fair offers and engaged less in third-party punishment. Impaired theory of mind in patients reduced the latter, but not the former, group difference to non-significance. No significant correlations emerged between symptom severity and task performance. Together, these findings suggest that the understanding of others' minds partly contributes to the appreciation of social rules and norms in patients with severe chronic courses of schizophrenia.

Deficit Versus Nondeficit Schizophrenia: An MEG-EEG Investigation of Resting State and Source Coherence-Preliminary Data

This study investigated the magneto- and electroencephalography (MEG and EEG, respectively) resting state to identify the deviations closely associated with the deficit syndrome (DS) in schizophrenia patients. Ten subjects in each group (control, DS, and nondeficit schizophrenia [NDS]) were included. Subjects underwent MEG-EEG recordings during a resting state condition. MEG coherence source imaging (CSI) in source space and spectral analysis in sensor space were performed. Significant differences were found between the 2 patient groups: (1) MEG and EEG spectral analysis showed significantly higher power at low frequencies (delta band) at sensor space in DS compared with NDS patients; (2) source analysis revealed larger power in the DS compared with NDS group at low frequencies in the frontal region; (3) NDS patients showed significantly higher MEG signal relative power in beta bands in sensor space compared with DS patients; (4) both DS and NDS patients showed higher EEG absolute power at higher beta band compared to controls; and (5) patients with DS were found to have a significantly higher MEG CSI than controls in the beta frequency band. These data support the observation of increased power in the low-frequency EEG/MEG rhythms associated with the DS. Increased power in the beta rhythms was more associated with the NDS.

Predictors of Placebo Response in Pharmacological Clinical Trials of Negative Symptoms in Schizophrenia: A Meta-regression Analysis

We conducted a meta-regression analysis of all double-blind, randomized, placebo-controlled clinical trials (DBRCTs) reporting effects of drug and placebo on negative symptoms in people with stable schizophrenia and predominant or prominent negative symptoms to assess predictors of placebo response in these individuals. We used Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for systematic reviews and meta-analyses to conduct a systematic literature search to identify DBRCTs assessing treatment efficacy on negative symptoms, as primary outcome, in patients with stable schizophrenia and predominant or prominent negative symptoms. We used Cohen's d, with 95% CIs, as the effect size measure for placebo response, based on negative symptom change scores from baseline to endpoint (range 4 to 24 wk) in the placebo-treated group. We included 18 DBRCTs from 17 publications, assessing the effect of 13 drugs vs placebo on negative symptoms and comprising 998 patients, in the meta-regression analyses. Overall, drugs showed greater efficacy than placebo in reducing negative symptoms, with small effect size (Cohen's d: 0.208, P = .020). Placebo response was significant (P < .001) and clinically relevant (Cohen's d: 2.909), but there was significant heterogeneity and high risk of publication bias. Multivariable meta-regression analyses showed that larger numbers of arms in the trial, larger numbers of study sites and industry sponsorship were significant moderators of placebo response in this population. Our results suggest that some clinical trial design and operational factors affect the level of placebo response in such studies, thus highlighting the need for designs better suited to assess these outcomes.

Attacking Heterogeneity in Schizophrenia by Deriving Clinical Subgroups From Widely Available Symptom Data

Previous research has identified (1) a "deficit" subtype of schizophrenia characterized by enduring negative symptoms and diminished emotionality and (2) a "distress" subtype associated with high emotionality-including anxiety, depression, and stress sensitivity. Individuals in deficit and distress categories differ sharply in development, clinical course and behavior, and show distinct biological markers, perhaps signaling different etiologies. We tested whether deficit and distress subtypes would emerge from a simple but novel data-driven subgrouping analysis, based on Positive and Negative Syndrome Scale (PANSS) negative and distress symptom dimensions, and whether subgrouping was informative regarding other facets of behavior and brain function. PANSS data, and other assessments, were available for 549 people with schizophrenia diagnoses. Negative and distress symptom composite scores were used as indicators in 2-step cluster analyses, which divided the sample into low symptom (n = 301), distress (n = 121), and deficit (n = 127) subgroups. Relative to the low-symptom group, the deficit and distress subgroups had comparably higher total PANSS symptoms (Ps < .001) and were similarly functionally impaired (eg, global functioning [GAF] Ps < .001), but showed markedly different patterns on symptom, cognitive and personality variables, among others. Initial analyses of functional magnetic resonance imaging (fMRI) data from a 182-participant subset of the full sample also suggested distinct patterns of neural recruitment during working memory. The field seeks more neuroscience-based systems for classifying psychiatric conditions, but these are inescapably behavioral disorders. More effective parsing of clinical and behavioral traits could identify homogeneous target groups for further neural system and molecular studies, helping to integrate clinical and neuroscience approaches.

Correlation of DRD2 mRNA expression levels with deficit syndrome severity in chronic schizophrenia patients receiving clozapine treatment

Schizophrenia is a complex, severe, chronic psychiatric disorder, and the associated deficit syndrome is widely regarded as an important clinical aspect of schizophrenia. This study analyzed the relationship of deficit syndrome severity with the mRNA levels of members of signaling pathways that associate with the pathophysiology of schizophrenia, including the dopamine D2 receptor (DRD2), protein kinase B (AKT1), and phosphoinositide-3 kinase (PI3KCB), in peripheral blood leukocytes (PBLs) of 20 healthy controls and 19 chronic schizophrenia patients with long-term clozapine treatment. The DRD2 expression levels in chronic schizophrenia group were statistically higher than those in controls (t=2.168, p=0.037). Moreover, in chronic schizophrenia group, correlations were observed between the expression levels of DRD2 and PI3KCB (r=0.771, p<0.001), DRD2 and AKT1 (r=0.592, p=0.008), and PI3KCB and AKT1 (r=0.562, p=0.012) and between the DRD2 mRNA levels and the Proxy for the Deficit Syndrome score (r=0.511, p=0.025). In control group, the correlation between PI3KCB expression levels and DRD2 expression levels was only observed (r=0.782, p<0.001). In conclusion, a correlation was observed between increased deficit syndrome severity and elevated expression levels of DRD2 in PBLs of chronic schizophrenia patients receiving long-term clozapine treatment.

Neurocognitive impairment in deficit and non-deficit schizophrenia: a meta-analysis

BACKGROUND

Most studies suggested that patients with deficit schizophrenia have more severe impairment compared with patients with non-deficit schizophrenia. However, it is not clear whether deficit and non-deficit schizophrenia are associated with differential neurocognitive profiles.

METHODS

The aim of this meta-analytic review was to compare cognitive performances of deficit and non-deficit patients with each other and with healthy controls. In the current meta-analysis, differences in cognitive abilities between 897 deficit and 1636 non-deficit patients with schizophrenia were examined. Cognitive performances of 899 healthy controls were also compared with 350 patients with deficit and 592 non-deficit schizophrenia.

RESULTS

Both deficit (d = 1.04-1.53) and non-deficit (d = 0.68-1.19) schizophrenia were associated with significant deficits in all cognitive domains. Deficit patients underperformed non-deficit patients in all cognitive domains (d = 0.24-0.84) and individual tasks (d = 0.39-0.93). The relationship between deficit syndrome and impairment in olfaction, social cognition, verbal fluency, and speed-based cognitive tasks were relatively stronger.

CONCLUSIONS

Our findings suggest that there is consistent evidence for a significant relationship between deficit syndrome and more severe cognitive impairment in schizophrenia.

Amelioration of deficit syndrome of schizophrenia by norepinephrine reuptake inhibitor

OBJECTIVE

Negative symptoms are a significant barrier to successful functional outcome and recovery in individuals with schizophrenia and their management is not unproblematic. Reboxetine is a norepinephrine reuptake inhibitor (NRI). Previous studies regarding the useful effects of reboxetine on deficit symptoms of schizophrenia have resulted in inconsistent results. The present study therefore evaluated the effectiveness of reboxetine as an adjunctive treatment in a group of schizophrenic patients with prominent negative symptoms.

METHOD

A total of 50 male inpatients meeting diagnosis of schizophrenia entered into a 12-week parallel group, double-blind study for random assignment to reboxetine (n = 25 patients) or placebo (n = 25 patients). The inclusion criterion, in addition to the diagnosis of schizophrenia, was the existence of obvious negative symptoms for a duration of at least 2 years. The Scale for Assessment of Negative Symptoms (SANS) was used as the primary outcome measure. The Scale for Assessment of Positive Symptoms (SAPS), Simpson Angus Scale (SAS), Hamilton Rating Scale for Depression (HAM-D) and Mini-Mental Status Examination (MMSE) were used for comparison of the intervening parameters in this study.

RESULTS

According to the findings, 76% of patients in the target group showed some positive response to reboxetine compared with 24% in the control group (p < 0.01). The mean total score of SANS in the reboxetine group decreased significantly from 79.94 ± 1.20 to 74.23 ± 4.07 (p < 0.0001) at the end of the study; such an improvement was not significant in the placebo group with a decrease from 80.42 ± 2.46 to 79.08 ± 5.83 (p < 0.29). Changes of SAPS were insignificant in both groups. Effect size analysis for changes of SANS at the end of assessment indicated a large improvement with reboxetine (Cohen's d = 2.91).

CONCLUSION

Reboxetine, as an adjuvant to haloperidol, may have a helpful effect on the deficit syndrome of schizophrenia.

Dysfunctional attitudes and expectancies in deficit syndrome schizophrenia

The deficit syndrome was proposed over 20 years ago as a separate negative symptom syndrome within schizophrenia with a distinct neurobiological pathophysiology and etiology. Recent research, however, has indicated that psychological factors such as negative attitudes and expectancies are significantly associated with the broad spectrum of negative symptoms. Specifically, defeatist beliefs regarding performance mediate between neurocognitive impairment and both negative symptoms and functional outcome. Additionally, asocial beliefs predict asocial behavior and negative expectancies regarding future pleasure are associated with negative symptoms. The present study explored whether these dysfunctional beliefs and negative expectancies might also be a feature of the deficit syndrome. Based on a validated proxy method, 22 deficit and 72 nondeficit patients (from a pool of 139 negative symptom patients) were identified and received a battery of symptom, neurocognitive, and psychological measures. The deficit group scored significantly worse on measures of negative symptoms, insight, emotion recognition, defeatist attitudes, and asocial beliefs but better on measures of depression, anxiety, and distress than the nondeficit group. Moreover, the deficit group showed a trend for higher scores on self-esteem. Based on these findings, we propose a more comprehensive formulation of deficit schizophrenia, characterized by neurobiological factors and a cluster of psychological attributes that lead to withdrawal and protect the self-esteem. Although the patients have apparently opted-out of participation in normal activities, we suggest that a psychological intervention that targets these negative attitudes might improve their functioning and quality of life.

Cortical structural abnormalities in deficit versus nondeficit schizophrenia

OBJECTIVE

To examine the structural integrity of the dorsolateral prefrontal-basal ganglia-thalamocortical circuit in people with the deficit form of schizophrenia.

METHOD

A three-dimensional structural MRI sequence was used to conduct morphometric assessments of cortical and subcortical regions in deficit and nondeficit outpatients with schizophrenia and healthy controls.

RESULTS

The superior prefrontal and superior and middle temporal gyral gray matter volumes were significantly smaller in the deficit versus the nondeficit group and normal control groups. There were no significant group differences in examined subcortical structures.

CONCLUSION

People with deficit schizophrenia are characterized by selective reductions in the prefrontal and temporal cortex.

Differential patterns of premorbid social and academic deterioration in deficit and nondeficit schizophrenia

Numerous studies indicate that social dysfunction is associated with negative symptoms of schizophrenia during the chronic phase of illness. However, it is unclear whether social abnormalities exist during the premorbid phase in people who later develop schizophrenia with prominent negative symptoms, or whether social functioning becomes progressively worse in these individuals from childhood to late adolescence. The current study examined differences in academic and social premorbid functioning in people with schizophrenia meeting criteria for deficit (i.e., primary and enduring negative symptoms) (DS: n = 74) and non-deficit forms of schizophrenia (ND: n = 271). Premorbid social and academic functioning was assessed for childhood, early adolescence, and late adolescence developmental periods on the Premorbid Adjustment Scale (PAS). Results indicated that both DS and ND participants showed deterioration in social and academic functioning from childhood to late adolescence. However, while ND schizophrenia demonstrated greater deterioration of academic compared to social premorbid functioning from childhood to late adolescence, the DS group exhibited comparable deterioration across both premorbid domains, with more severe social deterioration than the ND group. Findings suggest that people with DS show poorer social premorbid adjustment than those with ND as early as childhood, and are particularly susceptible to accelerated deterioration as the onset of schizophrenia becomes imminent. Thus, poor premorbid social adjustment and significant social deterioration from childhood to adolescence may be a hallmark feature of people who later go on to develop prominent negative symptoms and a unique marker for the DS subtype of schizophrenia.

Posttraumatic stress disorder and negative symptoms of schizophrenia

Posttraumatic stress disorder (PTSD) is highly comorbid with schizophrenia and may be associated with higher levels or lower levels of negative symptoms. In the current study, we attempted to clarify the relationship between PTSD and negative symptoms by examining the proportion of patients meeting various negative symptom criteria in a sample of patients diagnosed with schizophrenia alone or schizophrenia and comorbid PTSD. Results indicated that the presence of PTSD in schizophrenia was associated with increased secondary negative symptoms, with the deficit syndrome (DS) and primary negative symptoms associated with lower rates of current and lifetime diagnoses of PTSD. Furthermore, the deficit/nondeficit classification provided greater differentiation of PTSD symptoms than did negative symptoms defined more broadly using the Scale for the Assessment of Negative Symptoms or primary vs secondary distinctions. These findings suggest that DS patients are at a uniquely low risk for PTSD.

Impaired insight in patients with newly diagnosed nonaffective psychotic disorders with and without deficit features

Patients with schizophrenia who have primary, enduring negative symptoms, or the deficit syndrome, have poorer psychosocial functioning but lesser clinical distress compared with nondeficit patients. Poor awareness of impairment in patients with deficit schizophrenia may contribute to this seeming contradiction. We hypothesized that poor insight would be present early in the course of illness in deficit patients, and that those with deficit features would have greater impairment in insight than those without deficit features. One-hundred one first-episode patients with nonaffective psychotic disorders were categorized into deficit (n=31) and nondeficit (n=70) groups. The deficit patients had significantly poorer insight than nondeficit patients when rated using a self-report questionnaire, and nearly significantly poorer insight rated by clinical researchers. Further, this effect remained for self-rated insight and reached statistical significance for researcher-rated insight after controlling for positive, negative, and general psychopathology symptoms. These results suggest that the treatment of deficit patients may be particularly complicated by poor insight.

Periods of recovery in deficit syndrome schizophrenia: a 20-year multi-follow-up longitudinal study

Periods of recovery were examined in patients with and without deficit syndrome schizophrenia. Fifty-six patients with schizophrenia were studied, 39 of whom were divided into deficit and nondeficit syndrome schizophrenia subtypes using a proxy method. We also studied 39 nonpsychotic depressive comparison patients. Patients were evaluated as part of the Chicago Follow-up Study, which prospectively examined patients at regular intervals over a 20-year period. Using standardized instruments, patients were evaluated for the deficit syndrome, global recovery, rehospitalization, social dysfunction, occupational disability, and symptom presentation. Recovery was examined at 6 time points measured at 2-, 4.5-, 7.5-, 10-, 15-, and 20-year postindex hospitalization. Cumulatively, over the 20-year period, 13% of patients classified as meeting criteria for the deficit syndrome showed 1 or more 1-year periods of global recovery, in comparison to 63% of nondeficit schizophrenia patients and 77% of depressed patient controls. Results indicate that the deficit syndrome represents a persistently impaired subsample of schizophrenia patients, with continuous social, occupational, and symptom impairment. In contrast, nondeficit syndrome schizophrenia patients showed at least some periods of remission or recovery, with the likelihood of these periods increasing as they became older. Findings provide further support for the validity of the deficit syndrome concept and suggest that deficit status is characterized by a more persistently impaired course of illness and particularly poor long-term prognosis.

Differences in glucose tolerance between deficit and nondeficit schizophrenia

Some studies suggest that schizophrenia is associated with an increased risk of diabetes independently of antipsychotic use. People with deficit schizophrenia, which is characterized by primary (or idiopathic), enduring negative symptoms, differ from those with nondeficit schizophrenia on course of illness, treatment response, risk factors, and biological correlates. We hypothesized that deficit and nondeficit subjects would also differ with regard to glucose tolerance. Newly diagnosed, antipsychotic-naïve subjects with nonaffective psychosis and matched control subjects were administered a 75 g oral glucose tolerance test (GTT). Two-hour glucose concentrations were significantly higher in the nondeficit patients (N=23; mean [SD] of 121.6 [42.0]) than in deficit (N=23; 100.2 [23.1]) and control subjects (N=59; 83.8 [21.9]); the deficit subjects also had significantly higher two-hour glucose concentrations than did the control subjects. These results provide further support that the deficit group has a distinctive etiopathophysiology.

Elevated nailfold plexus visibility aggregates in families and is associated with a specific negative symptom pattern in schizophrenia

Twenty-four individuals with schizophrenia and 28 of their first-degree biological relatives were studied using clinical scales, functional ratings, and neuropsychological tests. An assessment of Nailfold Plexus Visibility (NPV) was also performed on these individuals. In keeping with the literature, we found an increased prevalence of high NPV in our schizophrenia subjects relative to controls and community norms, and also found that high NPV patients had significantly more negative symptoms and poorer social functioning. Measures of negative symptoms indicative of the deficit syndrome did a better job of distinguishing high from low NPV subjects than did more broadly defined negative symptom indices. As predicted, the prevalence of high NPV in first-degree relatives of high NPV schizophrenia subjects was increased compared with relatives of low NPV schizophrenia subjects. These two relative groups did not differ on overall level of schizotypy symptoms or on negative symptom schizotypy indices. However, relatives of low NPV patients scored significantly higher on scales of positive symptom schizotypy. Overall, these results support the hypothesis that high NPV is a marker of risk for a distinct subtype of schizophrenia.

Prevalence of 22q11.2 deletions in 311 Dutch patients with schizophrenia

The objectives of this study were 1) to examine whether the prevalence of 22q11.2 deletion syndrome (22q11DS) in schizophrenia patients with the Deficit syndrome is higher than the reported approximately 2% for the population of schizophrenia patients as a whole, and 2) to estimate the overall prevalence of 22q11DS among schizophrenia patients by combining all available studies. Our sample, enriched for patients with the Deficit syndrome, had 88% power to detect an estimated prevalence of 5% of 22q11.2 deletions. No 22q11.2 deletions were detected in 311 schizophrenia patients, 146 of whom met criteria for the Deficit syndrome. Our literature research revealed that in eight studies sixteen deletions were identified in 2133 patients with schizophrenia. This corresponds to a prevalence of 0.75% (95%CI: 0.5%-1.2%).

IN CONCLUSION

The prevalence of 22q11.2DS in schizophrenia patients with the Deficit syndrome is not higher than in the population of schizophrenia patients as a whole. The prevalence of 22q11.2DS in schizophrenia patients is lower than the frequently reported prevalence of 2% or more.

Validity of a 'proxy' for the deficit syndrome derived from the Positive And Negative Syndrome Scale (PANSS)

Schizophrenia patients with the deficit syndrome (DS) may represent a homogeneous subgroup. To increase the practicability of diagnosing the DS, Kirkpatrick et al. [Kirkpatrick, B., Buchanan, RW., Breier, A. Carpenter, WT., 1993. Case identification and stability of the deficit syndrome of schizophrenia. Psychiatry Res. 47, 47-56.] proposed the use of a 'proxy' case identification tool using standardized symptom ratings instead of the Schedule for the Deficit Syndrome (SDS) which requires an independent clinical assessment. The Proxy for the Deficit Syndrome (PDS) is based on the extraction of symptoms that are essentially equivalent or overlap substantially with the restricted affect and diminished emotional range on the SDS. Kirkpatrick et al. [Kirkpatrick, B., Buchanan, RW., Breier, A. Carpenter, WT., 1993. Case identification and stability of the deficit syndrome of schizophrenia. Psychiatry Res. 47, 47-56.] reported good sensitivity and specificity in a comparison of SDS and PDS assessments among 100 chronic schizophrenia outpatients. The present investigation involves the comparison of the deficit syndrome as assessed by the "gold standard" Schedule for the Deficit Syndrome with the ratings of the same symptoms embodied in the "proxy instrument" the PANSS, within the same group of 156 inpatients. Forty-four patients were assessed by the SDS to have the deficit syndrome. Patients with and without the DS, as defined by the SDS, did not differ for age, education, age at illness onset and duration of illness. The two main 'proxy' measures PDS1 and PDS2 discriminated across the SDS groups. The direct dichotomous comparison of the actual SDS and the 'proxy' derived PDS groups demonstrated good specificity (78.6% and 79.5%) and moderate to very good sensitivity (61.4% and 86.4%) and there was a moderately low rate of false positive cases (21.4% and 20.5%). For the two main 'proxy' measures (PDS1 and PDS2) kappas were .38 and .59, representing poor to good agreement. In our sample of rigorously diagnosed schizophrenia inpatients, the use of a 'proxy' case identification tool for the deficit syndrome would appear to be a viable alternative in identifying a subgroup of schizophrenia patients with the deficit syndrome when the use of the actual SDS is not feasible. Further study is indicated before the PDS as extracted from the PANSS can be used in lieu of the SDS for identifying patients with this syndrome.

Persistent negative symptoms in schizophrenia: an overview

Persistent negative symptoms represent an alternative approach for assessing negative symptoms in the context of clinical trials. Persistent negative symptoms are designed to capture those symptoms that lead to functional impairment but are currently understudied and for which there are no currently available effective treatments. Persistent negative symptoms differ from the 2 most commonly used approaches: primary, enduring negative symptoms or deficit symptoms and negative symptoms broadly defined to include negative symptoms, regardless of their etiology or duration. In contrast to deficit symptoms, persistent negative symptoms may include secondary negative symptoms. However, in contrast to negative symptoms broadly defined, the secondary negative symptoms included in the assessment of persistent negative symptoms only include those that have failed to respond to usual treatments for secondary negative symptoms. In consequence, the presence of persistent negative symptoms identifies a patient population with clinically relevant symptomatology, which is larger than the one with the deficit syndrome but less heterogeneous than that captured through the use of a nonrestrictive definition of negative symptoms. This may facilitate the selection of subjects for inclusion into research and efforts to develop new pharmacological treatments and enhance our understanding of a relevant clinical problem. Ultimately, the investigation of the different entities characterized by negative symptoms, such as persistent negative symptoms, and the enhanced understanding of their biological and clinical characteristics may help to unravel the psychopathological and biological heterogeneity of schizophrenia.

The factorial structure of the schedule for the deficit syndrome in schizophrenia

Deficit schizophrenia (DS) is considered a distinct subtype within the diagnosis of schizophrenia. While the common assumption is that DS represents a single, cohesive domain of psychopathology, the factorial structure of DS has not been investigated. We assessed 52 individuals with DSM-IV diagnoses of schizophrenia with DS. A principal component analysis (PCA) was conducted on the symptoms of the Schedule for the Deficit Syndrome. The PCA resulted in 2 distinct factors explaining 73.8% of the variance. Factor 1 (avolition) is made up of symptoms of curbing of interests, diminished sense of purpose, and diminished social drive. Factor 2 (emotional expression) is made up of symptoms of restricted affect, diminished emotional range, and poverty of speech. The results indicate that DS is best characterized by these 2 factors. The great majority of participants (86%) displayed DS symptoms from both factors. On average, participants had 4.19 (S.D. = 1.39) symptoms that were primary, enduring, and at least moderate in severity. The mean severity of symptoms was 2.25 (S.D. = 1.06). We discuss possible links between the obtained factors and putative neurobiological mechanisms, as well as directions for future research.

Odor identification, eye tracking and deficit syndrome schizophrenia

BACKGROUND

Deficit syndrome (DS) schizophrenia patients have smooth pursuit eye movement (SPEM) dysfunction. We examined if they also had smell identification deficits, since social affiliation is related to olfaction in other mammals.

METHODS

Sixty-seven patients had DS assessments: 31 patients had SPEM and 50 had Smell Identification Test (SIT) assessments, and 14 patients had both measurements.

RESULTS

DS patients had worse SPEM and SIT performance than the non-DS patients. Areas under the receiver-operator characteristic (ROC) curves for SIT and SPEM were both fairly accurate in identifying the DS. The odds ratio (OR) for the DS for impaired versus normal SPEM was 6.21 (95% confidence interval [CI]: 1.21, 32.25) and for microsmia versus normosmia was 10.4 (95% CI: 1.23, 88.18). Further analyses showed that the association of SIT with both SPEM and the DS could account for the SPEM-DS association.

CONCLUSIONS

We found a strong association between the DS and SIT scores suggesting that the neural substrates of olfaction may be related to social affiliation in humans, as they are in other mammals. These data further support the notion that the DS defines a homogeneous subgroup of schizophrenia patients and further suggest that dysfunction in the neural circuitry of olfaction may contribute to its pathophysiology.