Longitudinal trajectories of positive and negative schizotypy dimensions

Resumen

Schizotypy is operationalized as a continuum of personality traits, subclinical and clinical symptoms as well as impairment that, in its extreme form, is manifested as schizophrenia-spectrum disorders. Schizotypy and schizophrenia share a comparable multidimensional structure with positive and negative dimensions being the most strongly supported factors. Previous cross-sectional studies employing the psychometric high-risk strategy indicated that schizotypy is a useful method for identifying risk and resilience factors for the development of schizophrenia-spectrum psychopathology. However, longitudinal investigations remain scarce. This thesis includes three chapters investigating the predictive validity of positive and negative schizotypy dimensions, the temporal stability of schizophrenia-spectrum symptoms and traits in high schizotypy individuals, and the role of positive and negative schizotypy as potential distal risk markers moderating the association of stress with psychotic-like, paranoid, and negative symptoms experienced in the real life environment. Chapter 1 presents a study aimed at extending previous cross-sectional findings by investigating whether baseline psychometrically assessed negative and positive schizotypy differentially predict clinical risk symptoms, schizophrenia-spectrum personality disorders (PDs), and functioning in a nonclinical sample 3 years later. Additionally, this study examines the temporal stability of these constructs over a 1.4-year period. Both Time 1 (T1) schizotypy dimensions predicted schizotypal, paranoid, avoidant PDs, and functioning at Time 3 (T3). Positive schizotypy specifically predicted psychotic-like symptoms, depression, low self-esteem, and general psychopathology at T3. Negative schizotypy predicted emotional disturbances and schizoid PD at T3, as well as receiving mental health treatment over the past year. PDs, prodromal symptoms, and functioning assessed at Time 2 (T2) predicted the same constructs at T3. Chapter 2 describes a study aimed to extend our previous findings by examining whether longitudinal assessment of baseline positive and negative schizotypy at baseline predicted interview-based ratings of symptoms and impairment 4.4 years later. Furthermore, since the relationship between negative schizotypy traits and symptoms with depressive symptoms remains an unresolved issue, this study investigated the validity of negative symptoms as measured by two interview instruments. Baseline negative schizotypy uniquely predicted schizoid PD traits, negative symptoms, impaired functioning, and diminished positive self-schemas at the 4-year follow-up. Baseline positive schizotypy uniquely predicted avoidant PD traits and negative other-schemas. Both dimensions predicted schizotypal and paranoid PD traits, suspiciousness, depression, and negative self-schemas 4.4 years later. In addition, the two dimensions predicted positive symptoms (the effect size was larger for positive schizotypy) and diminished positive other-schemas (the effect size was larger for negative schizotypy). Baseline negative, but not positive, schizotypy predicted negative symptoms as assessed by CAARMS and NSM. However, only the prediction of NSM negative symptoms by negative schizotypy remained significant after controlling for affective dysregulation (i.e., dimensional scores of avoidant personality, anxiety and depression). Chapter 3 presents a study investigating the real-life expression of positive and negative schizotypy using the Experience Sampling Method. This study examined the prospective association of baseline positive and negative schizotypy as well as their cross-sectional association with schizotypic symptoms and experiences in daily life. Moreover, this report sought to extend previous research by investigating how daily life stress and social contact differentially predicted the real life expression of psychotic-like, paranoid, and negative symptoms in high schizotypy individuals.