Objective and subjective olfaction across the schizophrenia spectrum.

Much research indicates that patients with schizophrenia have impaired olfaction detection ability. However, studies of individuals with psychometrically defined schizotypy reveal mixed results-some document impairments while others do not. In addition to deficits in objective accuracy in olfaction for patients with schizophrenia, there has been an interest in subjective experience of olfaction. Unfortunately, methods of assessing accuracy and subjective hedonic olfactory evaluations in prior studies may not have been sensitive enough to detect group differences in this area. This study employed a measure of olfactory functioning featuring an expanded scoring system to assess both accuracy and subjective evaluations of pleasant and unpleasant experience. Data were collected for patients with schizophrenia, young adults with psychometrically defined schizotypy, psychiatric outpatients, and healthy controls. Results of this study indicate that both the schizophrenia and outpatient psychiatric groups showed similar levels of impaired olfaction ability; however, the schizotypy group was not impaired in olfaction detection. Interestingly, with regard to subjective hedonic evaluation, it was found that patients with schizophrenia did not differ from psychiatric outpatients, whereas individuals with schizotypy tended to rate smells as significantly less pleasant than healthy control participants. This suggests that subjective olfactory assessment is abnormal in some manner in schizotypy. It also suggests that accuracy of olfaction identification may be a characteristic of severe mental illness across severe mental illness diagnoses. The results are potentially important for understanding olfaction deficits across the mental illness spectrum.

A multidimensional assessment of social cognition in psychometrically defined schizotypy.

Individuals with schizophrenia exhibit impairments in multiple social cognitive domains. There is evidence that these impairments may be trait-related vulnerability markers for schizophrenia. However, the literature focusing on individuals vulnerable to developing schizophrenia-spectrum disorders, referred to as schizotypy, has produced inconsistent findings. This study's primary aim was to provide a more comprehensive understanding of social cognitive functioning within schizotypy than previous studies by employing a broad array of measures to assess multiple social cognitive domains, and examine how these domains relate to specific schizotypy traits (i.e., positive, negative, and disorganized) and Quality of Life (QOL). Facial emotion recognition, Theory of Mind (ToM), and aspects of emotional intelligence related to regulating one's own emotions (emotion management) and other's emotions (social management) were measured. Individuals with psychometrically defined schizotypy (n=36) and controls (n=26) were examined. The schizotypy group performed significantly worse than controls on facial emotion recognition, ToM, and emotion management, but not social management. Generally speaking, poorer social cognition performance was not a function of specific schizotypy traits. However, negative traits were associated with poorer facial emotion recognition, and disorganized traits were associated with better social management. Facial emotion recognition was associated with QOL in the schizotypy group.

Olfaction, "olfiction," and the schizophrenia-spectrum: an updated meta-analysis on identification and acuity.

Olfaction deficits in individuals with schizophrenia are well documented. A meta-analysis conducted nearly a dozen years ago on the topic revealed a deficit of a full standard deviation in magnitude compared to nonpatient controls. Recent efforts have been attempted to determine whether deficits in olfactory identification and acuity reflect a vulnerability marker of schizophrenia-spectrum pathology. To address this issue, the present study conducted a meta-analysis of 16 studies of individuals with schizotypy, defined in terms of a) "ultra-high risk" status, b) having an affected biological family member, or c) having extreme scores on a schizotypy questionnaire. We also conducted an updated meta-analysis of 40 studies of olfactory functioning in schizophrenia. Consistent with the prior meta-analysis, patients with schizophrenia showed impairments in olfaction identification on a full standard deviation in magnitude (d = -.99). Individuals with schizotypy showed much more subtle (d = -.24) differences in olfaction, though the effect sizes were higher for studies examining individuals at "ultra-high risk" (d = -.67) versus studies examining individuals with psychometrically-defined (d = -.14) schizotypy. Differences in olfactory acuity, relative to their respective control groups, were small for both the schizophrenia (d = -.45) and schizotypy (d = -.38) studies but were similar in magnitude. The present findings argue against the notion that deficits in olfaction identification are a vulnerability marker of schizophrenia. Suggestions for future research are recommended.

Towards a cognitive resource limitations model of diminished expression in schizotypy.

Diminished expression of speech is a pernicious feature of both schizophrenia and schizotypy--defined as the personality organization reflecting a putative genetic schizophrenia liability. As yet, the mechanism underlying diminished expression is unclear. We tested the hypothesis that diminished expression reflects a cognitive resource issue--that is, as cognitive resources are depleted, expression becomes diminished in individuals with psychometrically defined schizotypy. Acoustic analysis of natural speech was procured during experimentally manipulated baseline and high cognitive-load dual tasks and examined in 38 individuals with psychometrically defined schizotypy and 34 controls. For both groups, expression significantly decreased as a function of increased task demands, although there were no group differences in expression or magnitude of change across baseline to high cognitive-load conditions. Participants with self-reported constricted affect showed significant reductions in expression under high-load versus baseline speaking conditions relative to other schizotypal and control participants. Moreover, psychometrically defined schizotypal participants with poor cognitive performance on the high-load task, suggestive of depleted cognitive resources, also showed expressivity reductions compared with other participants. These findings suggest that diminished expression occurs as a function of limited cognitive resources in psychometrically defined schizotypy.

Affective disturbances in psychometrically defined schizotypy across direct, but not indirect assessment modes.

Affective disturbances in social domains are characteristic features and potential vulnerability markers of schizophrenia-spectrum pathology. The present study employed a comprehensive and multidimensional approach to understanding affect in individuals with psychometrically defined schizotypy and the controls. Measures were employed assessing trait and state social affective experiences across direct--involving explicit deliberative responses, and indirect domains--involving implicit, behavioral or otherwise non-deliberative responses. The indirect assessments included a modified Implicit Association Test and computerized lexical analysis of natural speech procured during a laboratory speech task. Our affect measures were also unique in that they allowed for separate measurement of pleasant and unpleasant affect. On all direct trait and "in-the-moment" state measures of social affect, individuals with schizotypy reported dramatically decreased pleasant and increased unpleasant affect compared to controls. This was not the case for the indirect measures, which indicated no significant group differences. This pattern was generally consistent regardless of positive, negative and disorganized schizotypal trait severity. These data suggest that affective deficits in schizotypy reflect deliberative rather than implicit/automatic processes. Implications of these findings are discussed.

The state-trait disjunction of anhedonia in schizophrenia: potential affective, cognitive and social-based mechanisms.

Dysfunctions in affective experience reflect a pernicious feature of schizophrenia-spectrum pathology that are largely intractable under current treatment regimens. Of note, individuals with schizophrenia show robust and marked deficits in the experience of pleasure when assessed using "trait" measures of affect (i.e., trait questionnaires and clinical interview), but fail to demonstrate this anhedonia "in the moment" using controlled laboratory mood-induction procedures. The reasons for this disjunction are unclear, but the last decade has seen a number of recent studies tackling this issue. We conduct a comprehensive review of this literature here. Five different explanations for this state-trait disjunction are identified: 1) anticipatory hedonic experience deficit, 2) affective regulation deficit, 3) encoding-retrieval deficit, 4) representational deficit and 5) social-specific deficit theories. Our present article reviews each of these theories, placing them in context of the larger affective and cognitive neuroscience literatures when appropriate. Additionally, practical recommendations for future studies examining affective dysfunction within the schizophrenia-spectrum are discussed.

The relationship between atypical semantic activation and odd speech in schizotypy across emotionally evocative conditions.

INTRODUCTION: Odd speech is prevalent in individuals with schizotypy compared to controls and this odd speech is particularly pronounced under stress-induced conditions. Despite a number of research studies that have examined odd speech, the mechanisms underlying this phenomenon remain unclear. There is reason to suspect that the increase in odd speech observed in schizotypy may reflect atypical semantic activation patterns, defined in terms of increased activation of weakly associated words within the semantic network. METHODS: In this study, we compared atypical semantic activation in individuals with a broad set of cognitive-perceptual, interpersonal and disorganization schizotypal traits (n=83) and controls (n=23). Odd speech was measured using a behavior-based analysis of natural speech procured from a laboratory speech-task involving separate experimentally manipulated stressful, pleasant, and neutral conditions. RESULTS: The schizotypy and control groups did not differ in semantic activation, but atypical semantic activation was more pronounced in individuals with disorganization traits and attenuated in those with interpersonal traits. Interestingly, the relationship between semantic activation and odd speech was observed for the stressful, but not pleasant or neutral conditions in the schizotypy group. CONCLUSIONS: These findings suggest that individuals with schizotypy may be able to inhibit atypical associations in nonstressful situations. However, their ability to prevent atypical semantic activation from affecting speech may be disrupted under stress, thus resulting in more odd speech. This study also highlights the dramatic differences in semantic activation across the various manifestations of schizotypy.

Toward a more psychometrically sound brief measure of schizotypal traits: introducing the SPQ-Brief Revised.

Psychometric case identification of individuals at risk for developing schizophrenia-spectrum disorders is an important enterprise. Unfortunately, current instruments for this purpose are limited. The present studies sought to improve the Schizotypal Personality Questionnaire-Brief (SPQ-Brief), a measure of schizotypal traits that has come under recent criticism. In the first study, we conducted exploratory factor analysis on the SPQ-Brief using a Likert-style scoring format in a large sample of nonclinical adults. Although acceptable internal consistency was found, the original factor structure was not supported. In the second study, we administered the full version of the SPQ to a separate large nonclinical adult sample and employed exploratory and confirmatory factor analysis to identify critical items that could be used to revise the SPQ-Brief. The end product of these studies is the SPQ-Brief Revised, which offers a subordinate seven-factor and super-ordinate three or four factor solution, employs a Likert-scale format to improve sensitivity, and is brief (34 items).

Facial emotion recognition in schizotypy: the role of accuracy and social cognitive bias.

Facial emotion recognition deficits have been widely investigated in individuals with schizophrenia; however, it remains unclear whether these deficits reflect a trait-like vulnerability to schizophrenia pathology present in individuals at risk for the disorder. Although some studies have investigated emotion recognition in this population, findings have been mixed. The current study uses a well-validated emotion recognition task, a relatively large sample, and examines the relationship between emotion recognition, symptoms, and overall life quality. Eighty-nine individuals with psychometrically defined schizotypy and 27 controls completed the Schizotypal Personality Questionnaire, Penn Emotion Recognition Test, and a brief version of Lehman's Quality of Life Interview. In addition to labeling facial emotions, participants rated the valence of faces using a Likert rating scale. Individuals with schizotypy were significantly less accurate than controls when labeling emotional faces, particularly neutral faces. Within the schizotypy sample, both disorganization symptoms and lower quality of life were associated with a bias toward perceiving facial expressions as more negative. Our results support previous research suggesting that poor emotion recognition is associated with vulnerability to psychosis. Although emotion recognition appears unrelated to symptoms, it probably operates by means of different processes in those with particular types of symptoms.

Decoupling implicit measures of pleasant and unpleasant social attitudes.

Social attitudes are integral to understanding a wide range of pathological states. The present study adapted the Implicit Association Test, a widely used implicit measure of attitudes, for understanding social attitudes and behavior. In a first study, data from a traditional "Bipolar" IAT and our modified "Unipolar" pleasant and unpleasant IATs were compared in their associations with explicit measures of social attitudes and behavior. In a second study, we examined the relationship between implicit measures of social attitudes and social behavior during a laboratory procedure. Collectively, the present data support the uncoupling of pleasant and unpleasant valences when using implicit measures to understand social attitudes.

The psychiatric symptomatology of deficit schizophrenia: a meta-analysis.

A relatively large literature has emerged supporting the notion that the deficit syndrome reflects a distinct illness within schizophrenia. One topic that has received limited attention is how deficit schizophrenia differs from nondeficit schizophrenia in terms of psychiatric symptomatology. The present study conducted a meta-analysis of 47 published studies to compare deficit and nondeficit patients in severity of positive, disorganization, negative, mood and total psychiatric symptoms. The patient groups did not differ in terms of positive or total psychiatric symptoms but deficit patients showed less severe mood symptoms and slightly more severe disorganization symptoms. Not surprisingly, deficit patients had much more severe negative symptoms. These results are discussed in terms of the construct validity of the deficit syndrome and the larger heterogeneity of schizophrenia. Additionally, diagnostic issues regarding the deficit syndrome are considered.

DCTN1 mutations in Perry syndrome.

Perry syndrome consists of early-onset parkinsonism, depression, severe weight loss and hypoventilation, with brain pathology characterized by TDP-43 immunostaining. We carried out genome-wide linkage analysis and identified five disease-segregating mutations affecting the CAP-Gly domain of dynactin (encoded by DCTN1) in eight families with Perry syndrome; these mutations diminish microtubule binding and lead to intracytoplasmic inclusions. Our findings show that DCTN1 mutations, previously associated with motor neuron disease, can underlie the selective vulnerability of other neuronal populations in distinct neurodegenerative disorders.