Schizotypy and individual differences in the frequency of normal associations in verbal utterances.

BACKGROUND: Recent empirical evidence [Maher, B.A., Manschreck, T.C., Linnert, J., Candela, S., 2005. Quantitative assessment of the frequency of normal associations in the utterances of schizophrenia patients and healthy controls. Schizophrenia Research 78, 219-224] shows that schizophrenia patients produce an elevated rate of normative thought associations in verbal utterances as measured by an objective computerized procedure. An important theoretical question concerns whether such an elevated rate of associative activity is due merely to psychosis, or can it be found in schizotypic subjects with no prior history of psychosis. METHODS: We hypothesized that schizotypic features should be correlated with associative performance, especially the positive symptom-like schizotypic features. The present study examined associative performance in psychometrically-identified schizotypic subjects (n=25) and normal control (n=29) subjects. We studied individual differences in schizotypal personality features in relation to the associative performance index. RESULTS: Level of normative associations was correlated with total schizotypic features, particularly those involving reality distortion and disorganization. Regression analysis revealed higher levels of disorganization features and lower levels of negative schizotypal features uniquely accounted for variation in the associative performance index. Partial correlation analysis suggested that the negative schizotypic features dimension may function as a suppressor variable moderating the relationship between disorganization and level of normative associations. CONCLUSIONS: Disorganization-related schizotypal features among individuals with no prior history of psychosis are correlated with elevated levels of normative associations. This relationship is most likely moderated by negative schizotypic features. These data support the presence of hyperassociative processes in those deemed to be at elevated risk for schizophrenia (or, more broadly perhaps, psychosis). Our findings support the utility of measuring associative performance using an objective measure and suggest that associative performance may be an endophenotype [Gottesman, I., Gould, T., 2003. The endophenotype concept in psychiatry: etymology and strategic intentions. American Journal of Psychiatry 160, 636-645] for schizophrenia.

Episodic chasing in pathological gamblers using the Iowa gambling task.

"Chasing ones losses" is a key symptom among pathological gamblers (PGs). This study focuses on quantitative differences in episodic chasing (i.e., sequences of disadvantageous decisions within a single gambling session) between PGs and non-pathological gamblers (NPGs). We compared 61 PGs and 39 NPGs on the Iowa Gambling Task (IGT) and the Zuckerman Sensation Seeking Scale (SSS). The PGs showed significantly more chasing and had significantly poorer decision-making strategies than NPGs, particularly among males (F = 4.52, p < 0.05). Random players were significantly less sensation seeking than advantageous and disadvantageous (i.e., chasing) players, but there was no interaction with group or gender. The results suggest that quantifiable within-session gambling behavior holds important implications for detecting underlying vulnerabilities to gambling pathology.

The relationship between delusions and hallucinations.

The origins of delusional beliefs have been a question of great interest for centuries. For many years, the widely held view was that there was a fundamental defect in reasoning in the patient that gave rise to the false belief. Much effort was directed at establishing the kind of defect and the circumstances that triggered it. The search for the basic reasoning defect has met with limited success, mainly because the flaws found in the reasoning of deluded persons are also found with substantial frequency in the general population. The co-occurrence of hallucinations and delusions is consistent with findings that repeated anomalous experiences of various kinds are followed by the development of delusions. In this case, it would be reasonable to regard the hallucinations as exercising a causative role in the development of delusions.

Paul E. Meehl's influence on experimental psychopathology: fruits of the nexus of schizotypy and schizophrenia, neurology, and methodology.

Paul E. Meehl made numerous contributions to clinical science and a hallmark of many of these contributions was their integrative nature. Meehl's positions on complex topics, especially one such as schizophrenia, were reflective of input from a variety of disciplines and levels of analysis. In this essay the authors focus on Meehl's uniquely rich contribution to our understanding of schizophrenia through his theoretical model of schizotypy, his abiding interest in exploring neurologically based indicators of schizophrenia liability and encouragement to others to pursue such indicators, and his passion for rigorous research methodology. Meehl's contributions in each of these areas continue to influence the direction and research strategies used in experimental psychopathology to illuminate the fundamental nature of schizophrenia. These contributions have also shaped inquiry into many other psychopathological entities.

Quantitative assessment of the frequency of normal associations in the utterances of schizophrenia patients and healthy controls.

BACKGROUND: The intrusion of associations into the utterances of schizophrenic individuals typically disrupts the coherence of the patient's utterances. Recent theoretical formulations of these phenomena have emphasized the hyperactivity) of associational networks in such language disturbance (e.g., Maher, B.A. 2003 Schizophrenia, aberrant utterance and delusions of control: the disconnection of speech and thought, and the connection of experience and belief. Mind and Language, 18, 1-22). There has been only limited effort to quantify such features in patient populations. METHODS: We hypothesized that (1) coherent utterances elicited from a sample of schizophrenia patients will present a higher mean frequency of normative associations than in normal controls; and (2) there is a positive association between total associations in utterances and hyperassociative activity (positive facilitation) as assessed by a semantic priming task. Participants included 43 schizophrenic patients and 25 healthy controls. Three measures were employed, a new computer program, Computed Associations in Sequential Text (CAST), to quantify normative associations; a picture description technique for eliciting speech samples; and a semantic priming task to measure associative facilitation. RESULTS: In coherent utterances, schizophrenia patients produced higher mean totals of associations compared to controls. Patients with positive facilitation scores in the controlled processing interval (1250 ms) of the semantic priming procedure, there was a correlation between facilitation scores and total frequency of associations. This effect was absent in controls. CONCLUSIONS: These results are consistent with models of language disturbance in schizophrenia that posit hyperactivity of associational networks.

Deconstructing, reconstructing, preserving Paul E. Meehl's legacy of construct validity.

The question of the status of cause-and-effect explanations of human behavior that posit physically existing causative factors and those that, on the other hand, posit hypothetical entities in the form of "useful fictions" has a long history. The influence of the works of Jeremy Bentham and Hans Vaihinger, as well as the later influence of Francis Galton, is described. Issues of the validity of hypothetical constructs and related problems of measurement and definition as found in psychoanalytic theory construction and in trait theory are examined. The significant and continuing interest generated by the landmark studies of K. MacCorquodale and P. E. Meehl (1948) and L. J. Cronbach and P. E. Meehl (1955) as well as the central importance of P. E. Meehl's thinking are described.

Earlier age of first diagnosis in schizophrenia is related to impaired motor control.

We examined the control of motor behavior in relation to age of first diagnosis (AFD; an approximation of age of onset) in schizophrenia. We hypothesized that earlier AFD reflects increased vulnerability to the disorder, vulnerability that may be indexed by elevated levels of motor abnormality. AFD, symptom and demographic features, motor performance on a line drawing task, and the presence and severity of dyskinesia and extrapyramidal side effects were evaluated in 65 chronic schizophrenia subjects. More severely impaired motor control was significantly related to an earlier age of diagnosis. Potential confounds, including age, gender, education, length of illness, current medication dosage, symptom status, and motor side effects, did not appear to influence this relationship, although greater chronicity appeared to be independently related to more severely impaired motor control. In summary, the data are consistent with the hypothesis that an earlier AFD is associated with more pronounced motor impairment.

Psychometric schizotypy and motor performance.

Motor abnormalities have long been a focus in discussions of schizophrenia. The present study used a newly developed line drawing task to examine fine motor performance and psychometrically assessed schizotypy in a large, randomly ascertained sample of young adults (N = 120) with no history of psychosis. Poor motor performance on the line drawing task, indexed by root-mean-square error (RMS), was significantly related to 4 separate psychometric measures of schizotypy in the overall sample. The psychometric schizotypy-RMS association remained significant for 2 of the schizotypy measures even when the effects of intellectual functioning, mental state factors, and sustained attention were statistically controlled in a regression analysis. The status of the line drawing index as a schizophrenia liability measure is discussed.

An afterword: the utility of cognitive models for the field of psychopathology.

Cognitive models of psychopathology provide opportunities and challenges for both the research psychopathologist and the clinician concerned with practical applications to individuals. Heterogeneity of individual pathology within diagnostic categories, heterogeneity of content within symptom categories, undue reliance on judgment-based ratings, and frequent emphasis on deficit rather than the overt behavior of the patients are some of the major issues. Others include the complex interaction between cognitive and affective processes and the fact that input-output functions are often nonlinear and marked by critical threshold values for the appearance of overt pathology. An important feature of models is the discipline that they introduce into theorizing about psychopathology plus the focus on precise quantification.