The impact of the COVID-19 pandemic on perceptions of social relationships, negative affect, and paranoid ideation.

The COVID-19 pandemic contributed to worsening mental health across the globe. The pandemic may have been especially impactful on those experiencing heightened psychosis spectrum symptomatology given greater pre-pandemic social isolation and increased vulnerability to stress. Yet, few studies exploring the impact of the COVID-19 pandemic on perceptions of social relationships and mental health have sampled individuals high in psychosis spectrum symptomatology, including those with psychosis spectrum disorders. Utilizing a mixed transdiagnostic community sample enriched for psychotic spectrum disorders, this longitudinal study investigated whether perceptions of social relationships and psychiatric symptoms changed during the COVID-19 pandemic, whether pandemic-related impacts were associated with social perceptions and symptomatology, and whether paranoid ideation was related to perceptions of the government response to the COVID-19 pandemic. Pandemic impacts were not uniform, with participants reporting a range of adverse impacts including poorer health-related behaviors, difficulties fulfilling basic needs, and medical related challenges. Results indicated that compared to pre-pandemic assessments, perceived rejection and hostility increased during the COVID-19 pandemic. Participants who experienced more pandemic-related impacts reported less social support, more social distress, greater negative affect, and greater paranoid ideation. Paranoid ideation was related to more negative perceptions of the government's response to the pandemic. These findings demonstrate the importance of assessing individual differences in pandemic-related impacts and the clinical consequences of such impacts. Results also suggest that those high in paranoid ideation may be reluctant to engage in government recommended protective health behaviors to limit the spread of COVID-19.

Interpersonal consequences of paranoid ideation, negative symptoms and sleep problems in a transdiagnostic sample of individuals with psychosis.

Paranoid ideation is a transdiagnostic construct that is associated with social impairment and often occurs in psychotic spectrum disorders. Little research has examined how paranoid ideation is related to social behaviors that underlie social impairment and may ultimately lead to social rejection. It is important to consider that negative symptoms and sleep problems also contribute to social impairment. No research has assessed the unique and combined influence of paranoid ideation, negative symptoms, and sleep problems on social impairment. Therefore, the current study examined how paranoid ideation, negative symptoms, and sleep problems contribute to poorer social skills and social rejection in a transdiagnostic sample of persons with psychosis and community members (N = 112). Assessments included diagnostic and symptom interviews, questionnaires, behavioral ratings of social skill and facial displays of affect, and naive observer reactions utilizing thin-slice methodology. Greater paranoid ideation, negative symptoms, and sleep problems were each related to poorer social skill and more negative reactions from observers. When considered in path analyses, negative symptoms were associated with observer reports of less willingness to interact with participants through poorer social skill. These findings demonstrate the symptom correlates of social rejection and how interpersonal behavior may contribute to social exclusion.

The Motivation and Pleasure Scale-Self-Report (MAP-SR): reliability and validity of a self-report measure of negative symptoms.

The Clinical Assessment Interview for Negative Symptoms (CAINS) is an empirically developed interview measure of negative symptoms. Building on prior work, this study examined the reliability and validity of a self-report measure based on the CAINS-the Motivation and Pleasure Scale-Self-Report (MAP-SR)-that assesses the motivation and pleasure domain of negative symptoms. Thirty-seven participants with schizophrenia or schizoaffective disorder completed the 18-item MAP-SR, the CAINS, and other measures of functional outcome. Item analyses revealed three items that performed poorly. The revised 15-item MAP-SR demonstrated good internal consistency and convergent validity with the clinician-rated Motivation and Pleasure scale of the CAINS, as well as good discriminant validity, with little association with psychotic symptoms or depression/anxiety. MAP-SR scores were related to social anhedonia, social closeness, and clinician-rated social functioning. The MAP-SR is a promising self-report measure of severity of negative symptoms.

Increasing social and community participation in veterans living with schizophrenia: A treatment outcome study.

People living with schizophrenia often face challenges engaging in social and community activities. A critical barrier is negative symptoms that reflect diminished feelings and thoughts that support social interaction. Several years ago, we began a process of specifying an intervention for individuals with schizophrenia and clinically meaningful negative symptoms that could be delivered in an integrated fashion with mental health services offered in VA medical centers with the primary focus of improving social and community engagement. In the present study, we examined the impact of a multi-component intervention to improve social and community participation in a group of Veterans living with schizophrenia and negative symptoms. We compared an intervention called Engaging in Community Roles and Experiences (EnCoRE) - a 12-week program of individual and group meetings that support learning and implementing skills with the goal of helping participants increase engagement in personally-relevant social and community activities - to an active wellness education control condition. Participants in both conditions attended on average of at least half of the groups that were offered, indicating that many individuals living with negative symptoms are willing to participate in an intervention to improve social and community participation. Although there were no significant differences on the two primary outcomes, those in EnCoRE showed better social and general functioning at post treatment and improved social motivational negative symptoms and decreases in perceived limitations at a 3-month follow-up. EnCoRE may be especially beneficial for participants who endorsed more dysfunctional attitudes about their abilities.

Understanding the Consequences of Moment-by-Moment Fluctuations in Mood and Social Experience for Paranoid Ideation in Psychotic Disorders.

Among individuals with psychotic disorders, paranoid ideation is common and associated with increased impairment, decreased quality of life, and a more pessimistic prognosis. Although accumulating research indicates negative affect is a key precipitant of paranoid ideation, the possible protective role of positive affect has not been examined. Further, despite the interpersonal nature of paranoid ideation, there are limited and inconsistent findings regarding how social context, perceptions, and motivation influence paranoid ideation in real-world contexts. In this pilot study, we used smartphone ecological momentary assessment to understand the relevance of hour-by-hour fluctuations in mood and social experience for paranoid ideation in adults with psychotic disorders. Multilevel modeling results indicated that greater negative affect is associated with higher concurrent levels of paranoid ideation and that it is marginally related to elevated levels of future paranoid ideation. In contrast, positive affect was unrelated to momentary experiences of paranoid ideation. More severe momentary paranoid ideation was also associated with an elevated desire to withdraw from social encounters, irrespective of when with familiar or unfamiliar others. These observations underscore the role of negative affect in promoting paranoid ideation and highlight the contribution of paranoid ideation to the motivation to socially withdraw in psychotic disorders.

Negative expectancy appraisals and defeatist performance beliefs and negative symptoms of schizophrenia.

Negative symptoms have clear functional implications in schizophrenia and are typically unresponsive to current treatments. The cognitive model of negative symptoms suggests that dysfunctional beliefs are influential in the development and maintenance of negative symptoms and schizophrenia. The current study reports on a preliminary investigation of a new measure of Negative Expectancy Appraisals (specifically beliefs about limited probability of success and perception of limited cognitive resources), and also evaluates whether dysfunctional beliefs are more closely linked to particular subdomains of negative symptoms. Sixty two individuals with schizophrenia completed measures of dysfunctional beliefs and were rated on negative symptoms. Analyses indicated that the endorsement of beliefs regarding low expectations for success and perception of limited resources (Negative Expectancy Appraisals) are robustly associated with diminished experience negative symptoms (avolition, asociality, and anhedonia), but are not associated with negative symptoms reflecting diminished expressivity (blunted affect, alogia). Similarly, Defeatist Performance Beliefs are modestly related to diminished experience, but not diminished expression, negative symptoms. Negative Expectancy Appraisals were also robustly linked to depressive symptoms. Results from the current study provide evidence that dysfunctional beliefs are clearly relevant to consider in relation to negative symptoms, and may represent a fruitful treatment target.

The challenges of fitting an item response theory model to the Social Anhedonia Scale.

This study explored the application of latent variable measurement models to the Social Anhedonia Scale (SAS; Eckblad, Chapman, Chapman, & Mishlove, 1982), a widely used and influential measure in schizophrenia-related research. Specifically, we applied unidimensional and bifactor item response theory (IRT) models to data from a community sample of young adults (n = 2,227). Ordinal factor analyses revealed that identifying a coherent latent structure in the 40-item SAS data was challenging due to (a) the presence of multiple small content clusters (e.g., doublets); (b) modest relations between those clusters, which, in turn, implies a general factor of only modest strength; (c) items that shared little variance with the majority of items; and (d) cross-loadings in bifactor solutions. Consequently, we conclude that SAS responses cannot be modeled accurately by either unidimensional or bifactor IRT models. Although the application of a bifactor model to a reduced 17-item set met with better success, significant psychometric and substantive problems remained. Results highlight the challenges of applying latent variable models to scales that were not originally designed to fit these models.

Assessing the psychometric properties of the PROMIS sleep measures in persons with psychosis.

An accumulation of research has indicated that persons with psychotic disorders experience a variety of sleep disturbances. However, few studies have examined the psychometric properties of sleep assessments that are utilized in this population. We conducted two studies to examine the reliability and validity of the PROMISTM Sleep Disturbance and Sleep-Related Impairment scales in outpatient samples of persons with psychosis. In Study 1, we examined the internal consistency and convergent validity of the PROMIS sleep scales in individuals with various psychotic disorders (N = 98) and healthy controls (N = 22). The PROMIS sleep scales showed acceptable internal consistency and convergent validity in both healthy controls and individuals with psychotic disorders. In addition, replicating prior research, the PROMIS scales identified greater sleep disturbance and sleep-related impairment in participants with psychotic disorders compared to healthy controls. In Study 2, we examined the test-retest reliability (M = 358 days) of the PROMIS sleep scales in a subset (N = 37) of persons with psychotic disorders who previously participated in Study 1. We also assessed the relation between these self-report measures and actigraph sleep parameters. The results showed that PROMIS sleep measures demonstrated modest temporal stability in the current sample. Contrary to our hypothesis, there was a lack of correspondence between these scales and actigraph sleep parameters. Overall, these findings indicate that the PROMIS sleep scales are psychometrically sound measures for populations with psychosis and highlight the importance of utilizing a multi-method approach to assess sleep.

Schizotypal, schizoid and paranoid characteristics in the biological parents of social anhedonics.

Mounting evidence suggests that social anhedonia may be a marker of genetic liability for schizophrenia-spectrum pathology. To examine this hypothesis, we conducted a study of severity of schizotypal, schizoid and paranoid pathology (i.e., Cluster A personality disorders) in the biological parents of individuals with high levels of social anhedonia and healthy controls. Eighty-six individuals with social anhedonia, 89 healthy controls and their biological parents were recruited from a large community. Structured clinical interviews were conducted to obtain Cluster A diagnoses and symptom ratings for parents. The biological parents of socially anhedonic probands had elevated rates of Cluster A disorders (24%) compared with the parents of control probands (12%). Post hoc analyses revealed that these group differences were the result of elevated rates of diagnoses in the fathers of social anhedonic probands, but not the mothers. This finding was replicated when Cluster A symptoms were examined dimensionally. These findings are consistent with the hypothesis that social anhedonia is a promising indicator of the genetic vulnerability to schizophrenia-spectrum pathology. The unexpected findings of elevated pathology in fathers, but not mothers of socially anhedonic probands, require further exploration.

Social anhedonia and clinical outcomes in early adulthood: A three-year follow-up study within a community sample.

Social anhedonia has been employed in psychometric high risk studies to identify putative schizotypes. The current study reports three-year longitudinal results from a community study of social anhedonia: the Maryland Longitudinal Study of Schizotypy (MLSS). The initial recruitment for the MLSS involved mailed questionnaire screening of 2434 18-year olds. Baseline and three-year follow-up laboratory assessments were subsequently conducted with individuals identified as being high in social anhedonia (N = 79) and a comparison sample (N = 79). Across the assessments both groups showed maturational improvement on all clinical symptom measures with declining symptom severity at the follow-up compared to baseline and there were no group differences in personality disorder diagnoses at follow-up. However, compared to the control group, over the three-year follow-up individuals in the social anhedonia group were found to have elevated schizophrenia-spectrum personality disorder (Cluster A) characteristics, greater negative symptom characteristics, and lower global functioning. The social anhedonia group also had lower educational attainment, higher unemployment, and higher rates of mental health service utilization than did the control group. Within the social anhedonia group, social support and family relationships were cross-sectionally related to symptom severity at follow-up, although social support and family variables from baseline were not predictive of clinical symptom outcomes at follow-up. Results indicate that social anhedonia is associated with persistent schizophrenia-spectrum symptoms and functional impairment in early adulthood.

Sleep disturbance and sleep-related impairment in psychotic disorders are related to both positive and negative symptoms.

A large literature indicates that sleep disturbances are associated with paranoia and other positive symptoms in psychotic disorders. However, few studies have examined the potential association between sleep disturbances and negative symptoms and the results have been inconsistent. The current study examined the hypothesis that sleep problems would be associated with more severe positive and negative symptoms in a transdiagnostic sample of individuals with psychosis (N = 90). Further, we examined whether sleep would be related to negative symptoms above and beyond the contribution of paranoia, other positive symptoms, and depression-anxiety. Results replicated prior research in finding that both sleep disturbance and sleep-related impairment were related to more severe paranoia, other positive symptoms and depression-anxiety. Consistent with our hypothesis, more severe sleep disturbance and sleep-related impairment were related to greater negative symptoms; this was evident across both motivation-pleasure deficits and diminished expression. Sleep variables remained significantly related to motivation-pleasure deficits even after controlling for other non-negative symptoms. These results indicate the broad symptom impact of sleep disturbances and may suggest a novel treatment target to improve negative symptoms.

Sleep Problems and Social Impairment in Psychosis: A Transdiagnostic Study Examining Multiple Social Domains.

Psychotic disorders are characterized by profound social impairment. An accumulation of research has explored the contribution of symptoms, cognitive functioning, and behavioral skills deficits to this social dysfunction. Recent research indicates that sleep disturbance has significant social implications in nonclinical populations-this research suggests that sleep problems may also be relevant to understanding social impairment in psychosis. This study adopted a symptom-oriented dimensional approach to examine how sleep disturbance and sleep-related impairment are related to multiple social domains within a transdiagnostic sample (N = 90). This sample included individuals with a variety of psychotic disorders (n = 75) along with healthy non-clinical participants (n = 15) to ensure sampling across the full range of sleep problems and social functioning. Social domains spanned self-reported perceptions of social relationships, social functioning in the community, and behavioral assessments of social competence. We hypothesized that greater sleep disturbance and sleep-related impairment would be associated with more negative or problematic perceptions of social relationships (i.e., less social support, less companionship, and greater distress), poorer social functioning in the community, smaller social networks, and poorer behavioral ratings of social competency. Results supported these hypotheses indicating that sleep disturbance and sleep-related impairment have widespread deleterious impacts on perceptions of social relationships, social functioning, and competence. Sleep disturbance retained associations with perceptions of social relationships, social functioning, and social competence even after controlling for total symptoms or cognitive functioning. These findings indicate that sleep problems may have important implications for fully understanding the causes of social impairment in psychosis.

A Randomized Clinical Trial of Oxytocin or Galantamine in Schizophrenia: Assessing the Impact on Behavioral, Lexical, and Self-Report Indicators of Social Affiliation.

Prior studies examining the impact of oxytocin on negative symptoms in schizophrenia have yielded mixed results. The current study explored whether oxytocin can improve more proximal indicators of social affiliation as indicated by changes in behavior, language and subjective indices of social affiliation among individuals with schizophrenia spectrum disorders during a role-play designed to elicit affiliative responses. We tested the hypothesis that daily intranasal oxytocin administered for 6 weeks would improve social affiliation as manifested by increased social skill ratings, use of positive, affiliative, and social words, and subjective responses from a previously published randomized controlled trial. Forty outpatients with schizophrenia or schizoaffective disorder were randomized to the oxytocin, galantamine, or placebo group and completed affiliative role-plays and self-report questionnaires of affect, reactions to the affiliative confederate, and willingness to interact at baseline and post-treatment. Results demonstrated that oxytocin was not effective at improving behavioral or subjective indicators of social affiliation. This study adds to a growing literature that the prosocial effects of oxytocin in schizophrenia are limited or null.

Affective traits in schizophrenia and schizotypy.

This article reviews empirical studies of affective traits in individuals with schizophrenia spectrum disorders, population-based investigations of vulnerability to psychosis, and genetic and psychometric high-risk samples. The review focuses on studies that use self-report trait questionnaires to assess Negative Affectivity (NA) and Positive Affectivity (PA), which are conceptualized in contemporary models of personality as broad, temperamentally-based dispositions to experience corresponding emotional states. Individuals with schizophrenia report a pattern of stably elevated NA and low PA throughout the illness course. Among affected individuals, these traits are associated with variability in several clinically important features, including functional outcome, quality of life, and stress reactivity. Furthermore, evidence that elevated NA and low PA (particularly the facet of anhedonia) predict the development of psychosis and are detectable in high-risk samples suggests that these traits play a role in vulnerability to schizophrenia, though they are implicated in other forms of psychopathology as well. Results are discussed in terms of their implications for treatment, etiological models, and future research to advance the study of affective traits in schizophrenia and schizotypy.

Assessing Social Affiliative Behavior: A Comparison of in Vivo and Video Tasks.

Social affiliation, or engagement in positive social interactions, is often profoundly impaired in individuals with schizophrenia. Valid measures of social affiliation are needed to understand these impairments and their symptom and functional correlates; however, such measures are limited and have not been validated. This pilot study evaluated one such measure-the video-based Social Affiliation Interaction Task (SAIT)-and a novel in vivo behavioral measure, the Affiliative Conversation Task (ACT). Twenty participants with schizophrenia or schizoaffective disorder (SZ) and 35 nonpsychiatric controls (CT) completed both tasks and measures of negative symptoms and functioning. We explored group differences in social affiliation skills; convergent validity between social affiliation skill ratings from the two tasks; and concurrent validity with social affiliation skill ratings, negative symptoms, and functioning. SZ evidenced lower affiliation skill ratings than CT on the video SAIT, but not on the ACT, and the tasks displayed moderate convergent validity for affiliation skill ratings. Less affiliation skill in the SAIT was correlated with more negative symptoms and less functioning in the SZ group with medium effects, though the results were not significant. Findings suggest that the SAIT may be more sensitive to individual differences in skill level. Future research should continue to examine the SAIT for use in measuring affiliation skills.

Negative symptoms and the formation of social affiliative bonds in schizophrenia.

Negative symptoms in schizophrenia are characterized by deficits in normative experiences and expression of emotion, and they are associated with poor social functioning. Negative symptoms relating to deficits in motivation and pleasure may hinder the development of affiliative bonds. The current study used a novel procedure to examine the relation between negative symptoms and the development of social affiliation within a laboratory setting. Fifty-five men (35 controls; 20 with a schizophrenia spectrum disorder) completed three Social Affiliation Enhancement Tasks with an experimenter partner. Self-reported affiliation and affect ratings were assessed before and after the affiliative interaction. Across groups, social affiliation and positive affect increased following the interactive tasks. However, the schizophrenia group reported less positive and more negative affect than controls. Within individuals with schizophrenia, negative symptoms reflecting motivation and pleasure deficits and self-reported social anhedonia were associated with less affiliative feelings of interpersonal closeness and less willingness to interact. Additionally, these self-reported reactions to the interaction partner were significantly related to social functioning in the community. These findings indicate that though individuals with schizophrenia can form affiliative bonds, the extent to which this is possible may be limited by negative symptoms relating to motivation and pleasure. Additional research will be necessary to examine just how these negative symptoms interfere with social affiliation.

Social anhedonia and schizotypy: the contribution of individual differences in affective traits, stress, and coping.

While social anhedonia is a promising indicator of vulnerability to schizophrenia, it remains uncertain whether anhedonia is a core feature of schizotypy or merely a secondary associated characteristic. This issue was examined by comparing dimensional scores on schizophrenia spectrum personality disorder symptoms derived from clinical interviews among three groups: a) "pure" social anhedonics with high scores on the Revised Social Anhedonia Scale (SAS; [Eckblad, M.L., Chapman, L.J., Chapman, J.P., Mishlove, M., 1982. The Revised Social Anhedonia Scale. Unpublished test, University of Wisconsin, Madison.]) and low scores on the Magical Ideation Scale (MIS, [Eckblad, M.L., Chapman, L.J., 1983. Magical ideation as an indicator of schizotypy. Journal of Consulting and Clinical Psychology, 51, 215-225.]), b) subjects with high MIS and low SAS scores, and c) controls with low scores on both scales. This study also sought to identify individual differences in stress reactivity, personality, coping style, and social support that might be related to severity of clinical symptoms among at-risk subjects. Compared to controls, the SAS group had higher levels of schizotypal, schizoid, and paranoid symptoms and the MIS group had higher schizotypal symptoms. Among social anhedonics, individual differences in perceived stress, trait negative affectivity, and coping style accounted for over 40% of the variance in schizotypal and paranoid symptoms. This cross-sectional study bolsters support for the validity of social anhedonia as a primary feature of schizotypy. Longitudinal studies are required to determine whether these individual differences potentiate clinical outcomes among social anhedonics.

Examining the reliability and validity of the Clinical Assessment Interview for Negative Symptoms within the Management of Schizophrenia in Clinical Practice (MOSAIC) multisite national study.

The current study sought to expand on prior reports of the validity and reliability of the CAINS (CAINS) by examining its performance across diverse non-academic clinical settings as employed by raters not affiliated with the scale's developers and across a longer test-retest follow-up period. The properties of the CAINS were examined within the Management of Schizophrenia in Clinical Practice (MOSAIC) schizophrenia registry. A total of 501 participants with a schizophrenia spectrum diagnosis who were receiving usual care were recruited across 15 national Patient Assessment Centers and evaluated with the CAINS, other negative symptom measures, and assessments of functioning, quality of life and cognition. Temporal stability of negative symptoms was assessed across a 3-month follow-up. Results replicated the two-factor structure of the CAINS reflecting Motivation and Pleasure and expression symptoms. The CAINS scales exhibited high internal consistency and temporal stability. Convergent validity was supported by significant correlations between the CAINS subscales with other negative symptom measures. Additionally, the CAINS was significantly correlated with functioning and quality of life. Discriminant validity was demonstrated by small to moderate associations between the CAINS and positive symptoms, depression, and cognition (and these associations were comparable to those found with other negative symptom scales). Findings suggest that the CAINS is a reliable and valid tool for measuring negative symptoms in schizophrenia across diverse clinical samples and settings.

Neuropsychological functioning and social anhedonia: results from a community high-risk study.

Social anhedonia has shown promise as a vulnerability marker for schizophrenia-spectrum pathology. Validity data have come, in part, from findings indicating that cognitive deficits occurring in schizophrenia are also evident in individuals with elevated levels of social anhedonia. However, prior research on this topic has been limited because it has been based almost exclusively on the study of selective samples of college students. The present article reports baseline findings of neuropsychological functioning in social anhedonics and controls from a representative community sample. Data on a wide array of neuropsychological abilities from 18-19 year-old participants with (n = 85) vs. without (n = 87) elevated levels of social anhedonia were analyzed. We hypothesized that, compared to controls, social anhedonics would show impairments in memory and sustained attention. Additionally, we sought to determine if more severe cognitive impairment in anhedonics was associated with greater schizophrenia-spectrum pathology and poorer overall functioning. Compared to controls, socially anhedonic participants performed more poorly on two visual-spatial memory tasks and a test of visual-spatial construction. The groups did not statistically differ on any of the other neuropsychological measures including general cognitive ability and sustained attention. Group differences were not the result of depression, bipolar or substance abuse disorders. Neuropsychological functioning showed little relationship to current clinical symptoms and functioning. Longitudinal assessment of these participants as they move through the risk period should provide important insights into the neuropsychological correlates of the schizophrenia prodrome.

Specific cognitive deficits and differential domains of social functioning impairment in schizophrenia.

There is considerable inconsistency in findings regarding the relationship between specific cognitive deficits and social impairment in patients with schizophrenia. This inconsistency may relate to variability across studies in how social functioning is measured and preliminary evidence suggests that different indices of social functioning (e.g., laboratory test, community assessment) may have different cognitive correlates. The present study examined this issue by evaluating the relationships between cognitive deficits (including social cognitive deficits), role-play test performance, and community social functioning in 28 inpatients with schizophrenia. We expected the two measures of social functioning to have only modest convergence with each other. Moreover, informed by the literature on cognitive functioning in schizophrenia, we identified specific cognitive processes that were hypothesized to be associated with role-play performance (delayed verbal memory and attentional vigilance) and social functioning in the community (delayed verbal memory and executive functioning). As expected, the two measures of social functioning were modestly correlated with each other. Community social functioning was associated with a relatively constrained pattern of cognitive deficits and received a significant contribution (Deltar2=0.24) from specific cognitive processes beyond that of general cognitive functioning and symptom severity. In contrast to our hypotheses, role-play test performance was associated with a wide range of cognitive impairments and received little contribution from the specific cognitive processes beyond the effects of general cognitive functioning. Community social functioning, but not role-play test performance, was significantly associated with social cognition. These findings highlight the importance of conceptualizing social functioning as a multidimensional construct for schizophrenia research.