Schizotypal personality disorder I: The clinical syndrome

BDNF val66met genotype and schizotypal personality traits interact to influence probabilistic association learning

The brain derived neurotrophic factor (BDNF) val66met polymorphism rs6265 influences learning and may represent a risk factor for schizophrenia. Healthy people with high schizotypal personality traits display cognitive deficits that are similar to but not as severe as those observed in schizophrenia and they can be studied without confounds of antipsychotics or chronic illness. How genetic variation in BDNF may impact learning in individuals falling along the schizophrenia spectrum is unknown. We predicted that schizotypal personality traits would influence learning and that schizotypal personality-based differences in learning would vary depending on the BDNF val66met genotype. Eighty-nine healthy adults completed the Schizotypal Personality Questionnaire (SPQ) and a probabilistic association learning test. Blood samples were genotyped for the BDNF val66met polymorphism. An ANOVA was performed with BDNF genotype (val homozygotes and met-carriers) and SPQ score (high/low) as grouping variables and probabilistic association learning as the dependent variable. Participants with low SPQ scores (fewer schizotypal personality traits) showed significantly better learning than those with high SPQ scores. BDNF met-carriers displaying few schizotypal personality traits performed best, whereas BDNF met-carriers displaying high schizotypal personality traits performed worst. Thus, the BDNF val66met polymorphism appears to influence probabilistic association learning differently depending on the extent of schizotypal personality traits displayed.

Schizotypal personality: neurodevelopmental and psychosocial trajectories

Schizotypal personality research holds the promise of critically important insights into the etiology and ultimate prevention of schizophrenia. This article provides a critical overview of diagnostic, developmental, demographic, psychosocial, genetic, neurodevelopmental, psychophysiological, neurochemical, neurocognitive, brain imaging, and prevention-treatment issues pertaining to this personality disorder. It is argued that genetic and early environmental influences act in concert to alter brain structure/function throughout development, resulting in disturbances to basic cognitive and affective processes that give rise to three building blocks of schizotypy-cognitive-perceptual, interpersonal, and disorganized features. Two clinical subtypes are hypothesized: (a) neurodevelopmental schizotypy, which has its roots in genetic, prenatal, and early postnatal factors, is relatively stable, has genetic affinity to schizophrenia, and may benefit preferentially from pharmacological intervention, and (b) pseudoschizotypy, which is unrelated to schizophrenia, has its roots in psychosocial adversity, shows greater symptom fluctuations, and may be more responsive to psychosocial intervention.

DSM-IV Cluster A personality disorder diagnoses among young adults with a 2-7-8 MMPI profile

The present study evaluated the presence of DSM-IV personality disorders among young adults from a nonclinical setting who produced an MMPI 2-7-8 profile in comparison to a group of MMPI-defined controls. Categorical and dimensional analyses of personality disorders were evaluated. Participants in the 2-7-8 group (n = 20) received significantly more personality disorder diagnoses than did controls (n = 29), and 85% of these individuals received at least one Cluster A (Paranoid, Schizoid, Schizotypal) diagnosis in contrast to only 6.9% of controls (categorical analysis). The 2-7-8 group also received significantly more Cluster A diagnoses than Cluster B or C diagnoses. When dimensional analyses were applied (subclinical diagnoses), 95% of the 2-7-8 group evidenced Cluster A features. Comorbidity patterns were also evaluated; the most frequent comorbid diagnosis for the 2-7-8 group was Avoidant Personality Disorder (n = 8), consistent with Meehl s (1962, 1989, 1990) conceptualization of schizotypy. These results support the use of the MMPI 2-7-8 profile as an indicator of schizophrenia-related pathology within nonclinical samples of young adults.