Elsevier

Psychiatry Research

Volume 198, Issue 2, 30 July 2012, Pages 241-247
Psychiatry Research

Neurological soft signs and psychometrically identified schizotypy in a sample of young conscripts

https://doi.org/10.1016/j.psychres.2012.03.007Get rights and content

Abstract

There is growing interest in the connection between neurological soft signs (NSS) and schizophrenia spectrum disorders such as schizotypal personality disorder. The association between NSS and schizotypy was investigated in a subgroup of 169 young healthy male military conscripts included in the Athens Study of Psychosis Proneness and Incidence of Schizophrenia. During their first 2 weeks in the National Basic Air Force Training Centre (T1—first assessment), subjects completed the Schizotypal Personality Questionnaire (SPQ), the Symptom Checklist-90—Revised (SCL-90-R), and the Raven's Progressive Matrices (RPM). Then, 2 years later (T2—second assessment), at the time of military discharge, they were tested for NSS with the Neurological Evaluation Scale (NES) and reevaluated with the SPQ, the SCL-90-R and additionally the Structured Clinical Interview for Personality Disorders (SCID-II) for the Diagnostic and Statistical Manual of Mental Disorders Third Edition, Revised (DSM-III-R). NSS were more prominent in conscripts with high schizotypy; scores on Sequencing of Complex Motor Acts (SCMA) and the “Other Soft Signs” (OSS) subscales were correlated with high schizotypy at both T1 and T2. Increased levels of SCMA as well as the total NSS score were correlated at both T1 and T2 with the interpersonal SPQ factor (reflecting negative schizotypy). The findings support the proposal that negative schizotypy might be associated with subtle neurodevelopmental abnormalities.

Introduction

Neurological ‘soft’ signs (NSS) are subtle neurological abnormalities pertinent to integrative sensory function, motor coordination and motor sequencing that are not attributed to specific brain areas (Buchanan and Heinrichs, 1989). It has been suggested that NSS might represent nonspecific cerebral dysfunctions in schizophrenia; Andreasen et al. (1998) hypothesized a disruption in a cortico-cerebellar-thalamic-cortical circuit leading to impaired sequencing and coordination of mental processes, manifested in symptoms associated with schizophrenia (cognitive dysmetria).

Compared with healthy controls, individuals with schizophrenia exhibit more NSS (Heinrichs and Buchanan, 1988, Arango et al., 1999, Dazzan and Murray, 2002, Keshavan et al., 2003, Bombin et al., 2005 Picchioni and Dazzan, 2009, Whitty et al., 2009, Chan et al., 2010a, Chan et al., 2010b). NSS have been observed in first episode schizophrenic patients (Dazzan and Murray, 2002), and in antipsychotic-naïve patients (Gupta et al., 1995). NSS may also occur before the onset of schizophrenia, in children (Walker et al., 1994), and in subjects at high risk of developing schizophrenia (Griffiths et al., 1998). Furthermore, elevated rates of NSS in healthy biological relatives of schizophrenic patients have been reported (Neelam et al., 2011), with NSS scores intermediate between those of patients and healthy controls (Egan et al., 2001, Yazici et al., 2002, Compton et al., 2007). It has been proposed that the presence of neurological abnormalities in groups at high risk for schizophrenia might represent a genetic vulnerability marker (Bachmann et al., 2005). A recent suggestion is that NSS might constitute a potential endophenotype for schizophrenia (Chan and Gottesman, 2008).

Regarding psychopathology, research findings suggest that NSS in schizophrenia are related to severe negative symptoms (Schröder et al., 1992, Malla et al., 1997, Arango et al., 2000, Dazzan and Murray, 2002, Yazici et al., 2002, Bombin et al., 2005, Ruiz-Veguilla et al., 2008, Chan et al., 2010a, Chan et al., 2010b) and disorganized symptoms (Schröder et al., 1996, Arango et al., 2000, Compton et al., 2007, Mechri et al., 2009). In contrast, positive symptoms seem unrelated to NSS (Bombin et al., 2005).

There is a growing interest in the connection between NSS and schizophrenia spectrum disorders like schizotypal personality disorder. Healthy individuals with schizotypy have been found to demonstrate increased numbers of NSS (Barrantes-Vidal et al., 2003, Barkus et al., 2006, Bollini et al., 2007, Keshavan et al., 2008, Kaczorowski et al., 2009, Prasad et al., 2009, Chan et al., 2010b, Mechri et al., 2010). Table 1 lists studies correlating schizotypy and NSS. It should be noted that the first, second, third, seventh and ninth studies (Obiols et al., 1999, Barrantes-Vidal et al., 2003, Barkus et al., 2006, Kaczorowski et al., 2009, Chan et al., 2010b) involved only healthy participants, while the fourth, fifth, sixth, and eighth studies (Bollini et al., 2007, Keshavan et al., 2008, Prasad et al., 2009, Mechri et al., 2010) also involved relatives of patients with schizophrenia or subjects at high risk for schizophrenia.

We sought to investigate potential associations between NSS and self-reported schizotypal traits in a sample of young healthy male conscripts (n  169) from the Athens Study of Psychosis Proneness and Incidence of Schizophrenia (ASPIS). Firstly, we sought to investigate potential correlations between NSS and schizotypy scores on the Schizotypal Personality Questionnaire (SPQ) in the entire sample. Secondly, the outcome was highlighted by comparing the NSS scores of conscripts with high schizotypy scores versus conscripts with average ones. Thirdly, regression models were implemented to validate the resulting associations by adjusting for possible confounding effects.

Section snippets

Setting and sample

A subgroup of 169 male subjects from the Athens Study of Psychosis Proneness and Incidence of Schizophrenia (ASPIS) were assessed for NSS at T2, 2 years after the first assessment for schizotypal features (T1), based on the following criteria derived from SPQ scores at T1: a) high scorers (who scored above the 90th percentile, 47%) and b) average scorers (who scored close to the mean value, 53%). Findings in the study by Raine (1991) indicated that 55% of those subjects who score in the top 10%

Descriptive indices

Table 3 presents the descriptive indices of Raven's Progressive Matrices (RPM), NSS, and SPQ scores. The four-factor solution (Stefanis et al., 2004) is presented. However, note that in the four-factor solution the Interpersonal/negative and the disorganized factors are identical with the three-factor solution; that is, they consist of the same items (Raine, 1991). SPQ scores were significantly lower at T2 (p < 0.001). The reduction varied from 42% to 62% at the SPQ subscale level.

Correlations of SPQ scores with NSS

At both time

Discussion

The results of the present study can be summarized as follows:

  • a)

    First, NSS were more prominent in healthy subjects with high negative schizotypy at both time points (T1 and T2), demonstrating temporal stability of this association. Specifically, the Sequencing of Complex Motor Acts (SCMA) subscale, and the total NSS scores were significantly correlated (p < 0.05) with the interpersonal factor at both time points (T1 and T2).

  • b)

    Second, NSS were more prominent in conscripts with high schizotypy; scores

Acknowledgements

This work was supported by the Grant EKBAN 97 to C.N.S. from the General Secretariat of Research and Technology of the Greek Ministry of Development. Intrasoft provided the technical support for this project.

References (74)

  • R. Emsley et al.

    Neurological abnormalities in first-episode schizophrenia: temporal stability and clinical and outcome correlates

    Schizophrenia Research

    (2005)
  • J.A. Kaczorowski et al.

    Neurological soft signs in psychometrically identified schizotypy

    Schizophrenia Research

    (2009)
  • M.S. Keshavan et al.

    Psychopathology among offspring of parents with schizophrenia: relationship to premorbid impairments

    Schizophrenia Research

    (2008)
  • M. Mayoral et al.

    Neurological soft signs in adolescents with first episode psychosis: two-year follow up

    Psychiatry Research

    (2008)
  • A. Mechri et al.

    Neurological soft signs and schizotypal dimensions in unaffected siblings of patients with schizophrenia

    Psychiatry Research

    (2010)
  • J.E. Obiols et al.

    Psychometric schizotypy and sustained attention in young males

    Personality and Individual Differences

    (1993)
  • J.E. Obiols et al.

    Neurological soft signs in adolescents with poor performance on the continuous performance test: markers of liability for schizophrenia spectrum disorders

    Psychiatry Research

    (1999)
  • K.M. Prasad et al.

    Neurological abnormalities among offspring of persons with schizophrenia: relation to premorbid psychopathology

    Schizophrenia Research

    (2009)
  • A. Raine et al.

    Increased psychophysiological arousal and orienting at ages 3 and 11 years in persistently schizotypal adults

    Schizophrenia Research

    (2002)
  • H. Rao et al.

    A regulation role of the prefrontal cortex in the fist-edge-palm task: evidence from functional connectivity analysis

    NeuroImage

    (2008)
  • M. Ruiz-Veguilla et al.

    Neurodevelopmental markers in different psychopathological dimensions of first episode psychosis: the ESPIGAS Study

    European Psychiatry

    (2008)
  • R.D. Sanders et al.

    Confirmatory factor analysis of the Neurological Evaluation Scale in unmedicated schizophrenia

    Psychiatry Research

    (2005)
  • J. Schröder et al.

    Memory deficits in subsyndromes of chronic schizophrenia

    Schizophrenia Research

    (1996)
  • N. Smyrnis et al.

    Effect of schizotypy on cognitive performance and its tuning by COMT val158 Met genotype variations in a large population of young men

    Biological Psychiatry

    (2007)
  • N.C. Stefanis et al.

    Psychometric properties of the Greek version of the Schizotypal Personality Questionnaire (SPQ) in young male obligatory conscripts: a two years test–retest study

    Personality and Individual Differences

    (2006)
  • J.A. Suhr et al.

    Factor versus cluster models of schizotypal traits: II. Relation to neuropsychological impairment

    Schizophrenia Research

    (2001)
  • M.T. Tsuang et al.

    An integration of schizophrenia with schizotypy: identification of schizotaxia and implications for research on treatment and prevention

    Schizophrenia Research

    (2002)
  • G. Venkatasubramanian et al.

    Neuroanatomical correlates of neurological soft signs in antipsychotic-naive schizophrenia

    Psychiatry Research: Neuroimaging

    (2008)
  • N.C. Andreasen et al.

    Cognitive dysmetria as an integrative theory of schizophrenia: a dysfunction in cortical–subcortical–cerebellar circuitry?

    Schizophrenia Bulletin

    (1998)
  • C. Arango et al.

    Prediction of neuropsychological performance by neurological signs in schizophrenia

    The American Journal of Psychiatry

    (1999)
  • C. Arango et al.

    Neurological signs and the heterogeneity of schizophrenia

    The American Journal of Psychiatry

    (2000)
  • S. Bachmann et al.

    Neurological soft signs in first-episode schizophrenia: a follow-up study

    The American Journal of Psychiatry

    (2005)
  • E. Barkus et al.

    The presence of neurological soft signs along the psychosis proneness continuum

    Schizophrenia Bulletin

    (2006)
  • G. Bersani et al.

    Deficit of executive functions in schizophrenia: relationship to neurological soft signs and psychopathology

    Psychopathology

    (2004)
  • I. Bombin et al.

    Significance and meaning of neurological signs in schizophrenia: two decades later

    Schizophrenia Bulletin

    (2005)
  • R.C. Chan et al.

    Neurological soft signs in schizophrenia: a meta-analysis

    Schizophrenia Bulletin

    (2010)
  • R.C. Chan et al.

    Neurological soft signs in individuals with schizotypal personality features

    The Australian and New Zealand Journal of Psychiatry

    (2010)
  • Cited by (15)

    • Motor dysfunction as research domain in the period preceding manifest schizophrenia: A systematic review

      2018, Neuroscience and Biobehavioral Reviews
      Citation Excerpt :

      A total of 26 studies that met the inclusion criteria were identified (Table 1). Among these studies, 14 investigated individuals with schizotypal personality traits (Theleritis et al., 2012; Kaczorowski et al., 2009; Wang et al., 2016; Chan et al., 2010a; Neumann and Walker, 1999; Mechri et al., 2010; Barkus et al., 2006; Lenzenweger and Maher, 2002; Mittal et al., 2008; Neumann and Walker, 2003; Chan et al., 2016; de Leede-Smith et al., 2017; Willems et al., 2016; Koning et al., 2011) and 12 studies examined UHR individuals (Bernard and Mittal, 2014; Dean et al., 2015; Mittal et al., 2010,2014,2007; Mittal and Walker, 2007; Bernard et al., 2014; Obiols et al., 1999; Callaway et al., 2014; Lawrie et al., 2001a; Caldani et al., 2017a,2017b). Among these studies, five used MRI to investigate GMA-related brain alterations in UHR individuals (Bernard et al., 2014; Bernard and Mittal, 2014; Dean et al., 2015; Mittal et al., 2010,2014).

    • Neurological soft signs: Effects of trait schizotypy, psychological distress and auditory hallucination predisposition

      2017, Schizophrenia Research: Cognition
      Citation Excerpt :

      Significant differences between schizotypy clusters were hypothesized for psychological distress, handedness and AVH predisposition. Concerning NSS, based on previous correlational research (e.g. Bollini et al., 2007; Chan et al., 2010b; Mechri et al., 2010; Theleritis et al., 2012) significantly greater NSS was predicted in the cluster that is characterized by elevated scores on multiple schizotypy dimensions. We also hypothesized that distress and handedness would have co-varying effects, accounting for a significant proportion of variance between schizotypal clusters in the expression of NSS.

    • Amotivation as central to negative schizotypy and their predictive value for happiness

      2014, Personality and Individual Differences
      Citation Excerpt :

      Negative schizotypal traits have been shown to be particularly stable and enduring (Stefanis et al., 2006). Furthermore, these traits have been linked to a host of other pathological features including, for example, neurological soft signs (Kaczorowski, Barrantes-Vidal, & Kwapil, 2009; Theleritis et al., 2012), neural processing of emotion (Germine, Garrido, Bruce, & Hooker, 2011), neural response to stress (Soliman et al., 2008; Soliman et al., 2011), and autistic features (Claridge & McDonald, 2009), to name a few. Given these abnormalities found in negative schizotypy, it is, perhaps, not surprising that these traits are associated with schizophrenia risk to a greater degree (Gooding et al., 2005; Kwapil, 1998).

    • Are neurological soft signs pre-existing markers in individuals with an at-risk mental state for psychosis?

      2013, Psychiatry Research
      Citation Excerpt :

      NSS were also found to be more frequent in nonpsychotic, genetically high-risk individuals with at least two first- and/or second-degree relatives with schizophrenia than in healthy controls (Gourion et al., 2004; Lawrie et al., 2001). Furthermore, in groups of normal volunteers, individuals presenting higher schizotypy showed significantly more soft signs as expressed by higher “Neurological Evaluation Scale” (NES) total scores and higher “Sequencing of Complex Motor Acts” and “Other Soft Signs” subscale scores (Barkus et al., 2006; Mechri et al., 2010; Theleritis et al., 2012). Neuroanatomical correlates of NSS were extensively investigated in healthy individuals.

    • Cold executive function processes and their hot analogs in schizotypy

      2023, Journal of the International Neuropsychological Society
    View all citing articles on Scopus
    View full text