Follow-up factor structure of schizotypy and its clinical associations in a help-seeking sample meeting ultra-high risk for psychosis criteria at baseline
Introduction
A dimensional rather than categorical view of psychotic symptoms has received support in recent years. Schizophrenia is at the extreme (clinical) end of the hypothesized extended phenotype, whereas schizotypy refers to cognitive, behavioural, and emotional traits that lie along this continuum [1]. Schizotypy is assumed to represent an underlying vulnerability for schizophrenia and to share etiological mechanisms [2], [3]. Significant rates of schizotypy in relatives of individuals with schizophrenia [4] and shared demographic and environmental risk factors [2] support this notion.
Schizotypy is a multifactorial construct, although the exact number and nature of the dimensions of schizotypy are highly dependent on sampling and methodology. In particular, the factor structure differs depending on the instrument used to assess schizotypal traits, which can make it difficult to compare findings on schizotypy and its associations [5]. Two-, 3-, 4-, and 5-factor models have been shown as plausible dimensional models of schizotypy [6], [7], [8]. Most commonly, there are 3 dimensions identified: a dimension of “positive schizotypy,” referring to classic psychotic traits such as unusual perceptual experiences and magical beliefs; an “interpersonal” dimension, comprising introversion and physical and social anhedonia; and a dimension associated with cognitive disorganisation [9], [10]. These are comparable with symptom subtypes (positive, negative, and disorganized) of schizophrenia [11], [12].
Bentall et al [13] and Claridge et al [7] identified a 4-dimensional structure of schizotypy, which includes a factor associated with impulsive, aggressive, and nonconforming aspects of behavior. The Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) was derived from these studies [14] and comprises 4 dimensions: Unusual Experiences (UE), Cognitive Disorganization (CD), Introvertive Anhedonia (IA), and Impulsive Nonconformity (IN). This 4-factor structure lacks validation [15], and to our knowledge, the 43-item O-LIFE short scales [16] have not been subjected to factor analysis.
If schizophrenia and schizotypy exist on the same extended psychosis phenotype, they would be expected to show similar associations, in a dose-response fashion, with psychopathology, functioning, and quality of life. Examining these associations in schizotypy may provide a better understanding of the mechanisms underlying schizophrenia, without the confounds that exist in patient groups, such as medication effects and stigma [1], [3], [5], [17].
Schizophrenia is frequently associated with other psychopathology, including affective dysregulation [18]. Most commonly, depressive symptoms have been linked to positive rather than negative symptoms [19], [20], [21]. This is not always the case, and associations may be dependent on illness phase [22]. Similarly, anxiety is more commonly associated with positive than negative symptoms [20], [23], although Tibbo et al [24] found no differences in the level of positive or negative symptoms between schizophrenia patients with and without comorbid anxiety.
Schizotypy is also hypothesized to be associated with emotional and behavioral dysfunction [1]. There is evidence that positive schizotypy is more closely associated with anxiety and depression than the interpersonal dimension of schizotypy in nonpsychotic psychiatric patients [25] and university students [17], [26], [27]. However, reports are not consistent. One study of adolescents showed that depression was more closely related to the disorganized and interpersonal factors of schizotypy [28]. Another found that emotional and behavioural problems were associated with all schizotypy dimensions, but most closely with disorganization. Using the O-LIFE to assess schizotypy in a nonclinical sample, depression was strongly associated with both IA and CD, whereas anxiety was most closely related to CD [29]. In another nonclinical sample, poorer general mental health was related to CD only [15].
Alternatively, quality of life and functional outcome in schizophrenia are more closely associated with the level of negative symptoms than positive (eg, Malla et al [30]). Less is known about the relationship between functioning and the dimensions of schizotypy. Two studies have found that poor functioning was strongly associated with higher scores on the positive and interpersonal schizotypy dimensions [17], [26], but the interpersonal dimension of schizotypy appears to be most closely associated with poorer quality of life [17], [31]. More research is needed to clarify the relationship between the dimensions of schizotypy and other clinical indices.
In the present study, we investigated the dimensions of schizotypy indexed on the O-LIFE and their associations with psychopathology, functioning, and quality of life in a sample assessed at follow-up and that had originally been help-seeking and identified as meeting criteria for “ultra-high risk” (UHR) for psychosis. This sample was selected because it was enriched for schizotypy based on the overlap between UHR criteria and the schizotypy construct [3]. Ultra-high risk criteria (also see Method) include attenuated psychotic symptoms (APS) and trait vulnerability for psychotic illness (schizotypal personality disorder and familial risk for psychosis) [32], [33]. Therefore, this is a useful sample in which to investigate the relationship between dimensions of schizotypy and their associations. It was hypothesized that:
- 1.
The 4-factor structure of the O-LIFE short scales would be confirmed.
- 2.
Higher schizotypy would be associated with greater psychopathology and poorer functioning and quality of life.
- 3.
Scores on UE and IA would be positively correlated with positive and negative symptom scores on the Brief Psychiatric Rating Scale (BPRS)–psychotic subscale and Scale of Assessment for Negative Symptoms (SANS), respectively.
- 4.
Depression and anxiety would be most closely associated with UE and CD, whereas functioning and quality of life would be strongly associated with IA.
Section snippets
Participants and procedure
The current data are part of a follow-up study of help-seeking research participants seen at the Personal Assessment and Crisis Evaluation (PACE) Clinic between 1993 and 2006 (n = 416). PACE is a specialist service for youth at UHR for psychosis in Melbourne, Australia. At baseline, participants were aged 15 to 30 years and met UHR criteria, operationalized on the Comprehensive Assessment of At-Risk Mental States (CAARMS) [34]. Ultra-high risk criteria are the following: (1) APS; (2) brief
Results
The mean age of this sample was 25.7 years (SD, 4.9), and 59.2% were female. Forty-four (19.3%) participants had transitioned to threshold level psychosis over the follow-up period. Current APS were assessed using the CAARMS. Of the 44 participants who had transitioned, 23 exhibited APS at the time of assessment. Of the 184 participants who had not transitioned to psychosis, 62 were currently experiencing APS (ie, they would still be UHR for psychosis if level of functioning was low or had
Discussion
The current study investigated the 4-dimensional structure of the O-LIFE short scales at follow-up in a help-seeking sample that was identified as UHR for psychosis at baseline and thus enriched for schizotypy. We explored associations between the dimensions of schizotypy and psychopathology, functioning, and quality of life. Impulsive Nonconformity was an unstable factor and was excluded from analyses. The 3 more robust factors of the O-LIFE were differentially associated with clinical
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Cited by (0)
Location of work: This project was conducted at Orygen Youth Health Research Centre.
- 1
Contributed equally.