واکنش پذیری عاطفی اختلالات گفتار در اسکیزوتایپی

Abstract Speech disturbances (SD) are a pernicious symptom of schizophrenia that increase when negative emotion is elicited. This increase is referred to as affective reactivity (AR). Although considerable research has examined SD in schizophrenia, few studies have investigated this symptom in individuals at risk for the disorder, who demonstrate schizophrenia-like, or schizotypic, traits. In the present study, we examined: (1) SD severity in schizotypy, (2) how SD varies as a function of stress reactivity in schizotypy, and (3) the relationship between SD/AR with Quality of Life (QOL). Individuals with psychometrically-defined schizotypy (n = 83) and controls (n = 22) completed a laboratory procedure in which they produced speech while viewing pleasant and stressful photographs. This speech was analyzed for subtle speech disorder using a well-validated measure. We found that the schizotypy group demonstrated significant increases in SD across both baseline and stressful conditions compared to the control group. AR was not significantly different between the groups. Within the schizotypy group, severity of disorganized schizotypy symptoms was associated with high levels of SD and AR while interpersonal schizotypy was associated with low levels of SD and AR. AR was also related to increased objective QOL in the schizotypy group. This study highlights the role of stress reactivity across the schizophrenia-spectrum. Moreover, the incongruous relationships between disorganized and interpersonal symptoms with SD underscore the marked heterogeneity in processes across schizotypy.

Introduction Speech disturbance (SD) is a stable symptom of schizophrenia believed to be reflective of thought disorder. In patients, speech errors were first described by Bleuler, who introduced the term ‘loosening of associations’ to reflect a critical aspect of thought disorder that lead to an interruption in the associative threads that guide thinking (Bleuler, 1911). Loss of goal-directed thought and loose associations are often manifested in speech, as patients with schizophrenia frequently construct sentences in which two unrelated ideas are associated or reply in a way that has little to do with the topic (McKenna and Oh, 2005). Often, the speaker uses phrases containing ambiguous or unclear references, making it difficult for the listener to determine meaning (Docherty et al., 1996). A burgeoning line of research has demonstrated that, in patients with schizophrenia, certain speech errors, detectable only when using a subtle measure of SD, increase when negative emotion is aroused. This condition is often referred to as affective reactivity (AR) (Docherty et al., 1994 and Docherty and Hebert, 1997). This line of research is important because it could potentially elucidate differences in how individuals with schizotypy respond to stress, a factor that evidence has shown plays an important role in the progression of schizophrenia (Myin-Germeys et al., 2001; 2002; 2003; 2005; Norman and Malla, 1993 and Ventura et al., 1989). According to Meehl (1962), individuals with a genetic vulnerability to developing schizophrenia-spectrum disorders, also known as schizotypy, who encounter sufficient life stressors will develop schizophrenia. Zubin and Spring (1977) expanded on Meehl’s work to describe the diathesis-stress model of schizophrenia, which further clarified the relationship between underlying vulnerability and stress in the onset of schizophrenia. As yet, however, there is limited exploration of the extent to which SD or AR occurs in individuals with schizotypy. A recent study by Kerns and Becker (2008) found that individuals with elevated disorganized schizotypy symptoms had a higher incidence of SD compared to controls when discussing negative topics. No significant differences were observed between the two groups when positive topics were discussed, which suggests that increases in SD may only be apparent in individuals with schizotypy when negative emotion or stress is elicited. A significant hurdle in understanding both schizophrenia and schizotypy is heterogeneity. There is no metabolic, genetic, neuroanatomical, neuropsychological deficit or symptom that is present in all, or even most cases of schizophrenia (Cohen and Docherty, 2005a and Menezes et al., 2006). Within patients, Docherty and colleagues have proposed that AR reflects an individual difference variable that is reflective of a more general physiological and phenomenological reactivity (Docherty et al., 1996, Docherty and Hebert, 1997 and Docherty et al., 2001). Thus, AR may reflect a marker of disease process that identifies a subtype of schizophrenia that is pathophysiologically distinct from that seen in other patients (Docherty et al., 2001 and Docherty and Grillon, 1995). In the current study, we used the three-factor model of schizotypy to investigate the influence of individual symptoms. This model consists of: (1) cognitive perceptual, (2) interpersonal deficits, and (3) disorganized symptoms (Chen et al., 1997, Fossati et al., 2003 and Raine et al., 1994). At present, no studies have examined SD or AR in accordance with the three-factor model of schizotypy. Although Kerns and Becker (2008) observed a significant relationship between disorganized schizotypy and SD in stressful speech conditions, no researchers have investigated SD or AD across cognitive-perceptual or interpersonal symptoms. In patients with schizophrenia, however, positive symptoms are associated with increased SD during stressful conditions (Docherty et al., 1994 and Docherty and Hebert, 1997) and negative symptoms are related to lower AR (Cohen and Docherty, 2004). It is also important to understand the degree to which SD and AR affect “real-world” functioning. In both patients with schizophrenia (Bengtsson-Tops and Hansson, 1999 and Ho et al., 1998 and individuals with schizotypy (Cohen and Davis, in press and Henry et al., 2008), Quality of Life (QOL) has been shown to be impoverished. This is especially true when examining functioning in social domains, with both friends (Aguirre et al., 2008 and Ballon et al., 2007) and family members (Aguirre et al., 2008). It serves to reason that since communication is such an important component in relating to others, that relationships with friends and family members would be adversely impacted in individuals who have increased SD, or who demonstrate more SD when they feel stressed (reflected by higher AR). Other aspects of QOL may also be affected. Although it is known that both SD and AR are increased in patients and that some QOL domains are negatively impacted in both patients and individuals with schizotypy, it is unclear if SD/AR and QOL are related. In the current study, we investigated three hypotheses. First, we hypothesized that individuals with schizotypy would have an increase in both SD and AR compared to controls. Second, our expectation was that, within the schizotypy group, cognitive-perceptual and disorganized symptoms would be associated with increases in SD and AR, while interpersonal symptoms would not be associated with SD or AR. Finally, we investigated whether subjects exhibiting increased rates of SD and AR have a significantly lower QOL rating compared to participants with few SD and AR.

. Results 3.1. Demographic comparisons To begin, we examined group demographic factors to identify potential confounds in later analyses. Complete demographic data are contained in Table 1. No significant differences were observed between the groups on any demographic variables (all p < .05). The schizotypy group demonstrated significantly lower scores than the control group on all QOL domains, except for Objective Family QOL, t(103) = 1.13, p = 0.26, where no significant difference was observed. Table 1. Demographic data for participants in the control and schizotypy groups. Schizotypy (N = 83) Control (N = 22) Test statistic Age 19.18 ± 1.42 19.86 ± 3.50 1.41 Gender 0.54 Male 27 (33%) 9 (41%) Female 56 (67%) 13 (59%) Ethnicity 8.95 Caucasian 74 (89%) 17 (77%) African–American 2 (2%) 4 (18%) Other ethnicity 7 (8%) 1 (5%) Highest grade level 1.50 High school graduate or below 47 (57%) 9 (41%) 1+ Year of college completed 22 (27%) 6 (27%) 2+ Years of college completed 14 (17%) 7 (32%) Current GPA 0.37 <2.0 9 (11%) 0 (0%) 2.0–2.99 26 (31%) 14 (64%) 3.0–4.0 48 (58%) 8 (36%) Mother’s education 1.86 High school graduate or below 23 (28%) 4 (18%) Some college or college graduate 53 (64%) 14 (64%) Master’s or doctoral degree 7 (8%) 4 (18%) Father’s education 1.19 High school graduate or below 19 (23%) 4 (18%) Some college or college graduate 42 (51%) 9 (41%) Master’s or doctoral degree 22 (27%) 9 (41%) Hours worked/week 10.94 ± 9.67 9.77 ± 10.74 −0.49 Quality of Life Subjective Total QOL 34.81 ± 6.76 46.09 ± 5.18 7.27⁎⁎ Objective Social QOL −9.04 ± 3.62 −6.32 ± 2.10 3.35⁎⁎ Subjective Social QOL 4.27 ± 1.62 6.23 ± 0.87 5.48⁎⁎ Objective Family QOL −3.95 ± 1.39 −3.59 ± 1.05 1.13 Subjective Family QOL 4.84 ± 1.51 6.14 ± 1.17 3.73⁎⁎ Objective financial QOL −2.98 ± 1.62 −1.77 ± 1.11 3.27⁎⁎ Subjective financial QOL 3.96 ± 1.78 5.36 ± 1.33 3.43⁎⁎ ⁎⁎ p < .01. Table options 3.2. Speech disturbances The results of the ANOVA (Table 2) indicated significant main effects for group (F[1, 103] = 3.10, p < .05, baseline d = 0.40, stressful d = 0.32) and condition (F[1, 103] = 10.12, p < .01, control d = 0.40, schizotypy d = 0.40). Across both conditions, the schizotypy group exhibited increased SD compared to the control group. In addition, both groups produced significantly higher SD in the stressful compared to the baseline condition. The group X condition interaction was not significant (F[1, 103] > 0.01, p = .95). These data suggest that the schizotypy group demonstrated significantly more overall SD compared to controls, but that speech disorder did not dramatically increase as a function of stress for individuals with schizotypy as a group. Table 2. Analysis of variance comparing schizotypy and control groups on speech disturbances (SD) across conditions. Control (n = 22) Schizotypy (n = 83) SD: baseline condition Mean ± StDev 1.66 ± 0.79 2.00 ± 0.93 SD: stressful condition Mean ± StDev 2.04 ± 1.12 2.36 ± 0.88 Table options 3.3. Affective reactivity Baseline SD scores were statistically regressed from stressful SD scores for the entire sample. Comparing schizotypy and controls revealed no significant differences t(103) = −0.56, p = 0.58. As above, we are unable to provide evidence for our hypothesis that individuals with schizotypy, on the whole, are more reactive to stress than the control group. 3.4. Schizotypy symptoms and SD/AR Within the schizotypy group, no significant correlations were observed between cognitive-perceptual, disorganized or interpersonal scores and baseline (or pleasant) SD scores (Table 3). However, disorganized symptoms were significantly associated with more severe SD in the stressful condition. Moreover, interpersonal symptoms were significantly associated with less severe SD in the stressful condition. In this analysis, evidence supporting our hypothesis that disorganized symptoms would be associated with SD was provided. However, a significant relationship between cognitive-perceptual symptoms and SD was not observed. Table 3. Bivariate correlations between specific symptoms of schizotypy, Quality of Life (QOL) domains, speech disturbances, and affective reactivity (df = 81). Schizotypy symptoms Speech disturbance: baseline Speech disturbance: stressful Affective reactivity Cognitive- perceptual schizotypy Disorganized schizotypy Interpersonal schizotypy Cognitive-perceptual schizotypy −0.08 0.12 0.20⁎ – 0.26⁎ −0.25⁎ Disorganized schizotypy 0.17 0.28⁎⁎ 0.18⁎ 0.26⁎ – −0.34⁎⁎ Interpersonal schizotypy −0.07 −0.33⁎⁎ −0.31⁎⁎ −0.25⁎ −0.34⁎⁎ – QOL Objective Total QOL 0.01 <0.01 −0.01 −0.16 −0.16 −0.08 Subjective Total QOL 0.01 <0.01 −0.01 −0.22⁎ −0.01 −0.23⁎ Objective Social QOL −0.13 0.19 0.29⁎⁎ 0.26⁎ 0.20 −0.43⁎⁎ Subjective Social QOL 0.06 0.14 0.11 0.08 0.16 −0.41⁎⁎ Objective Family QOL −0.01 −0.13 −0.12 −0.14 −0.16 0.03 Subjective Family QOL <0.01 −0.09 −0.10 −0.33⁎⁎ −0.15 −0.02 Objective Financial QOL 0.21 0.01 −0.14 −0.11 0.01 0.01 Subjective Financial QOL 0.07 0.05 0.01 −0.21 <0.01 0.01 ⁎ p < .05. ⁎⁎ p < .01. Table options Correlations were also conducted to test whether AR was related to schizotypy symptoms. A significant inverse correlation was observed between AR and interpersonal schizotypy. Positive correlations were found when AR was correlated with disorganized and cognitive-perceptual symptoms. Our hypotheses that cognitive-perceptual and disorganized symptoms would be associated with AR were supported, and an unexpected inverse correlation was observed between interpersonal schizotypy and AR. 3.5. QOL and SD/AR There were no significant associations between AR or SD and Subjective QOL in any measured domain (Table 3). However, one significant finding was observed in regard to Objective QOL. AR was related to improved Objective Social QOL, indicating that participants’ relationships with friends were rated as more being positive as AR increased. From these analyses, we fail to reject the null hypothesis and demonstrate that AR is inversely correlated with QOL. In fact, the one significant association that we observed was in the opposite direction as was expected.