Inventory identification of cyclothymia. IX. Validation in offspring of bipolar I patients.

We present the ninth in a series of validation studies that support the effectiveness of the General Behavior Inventory (GBI) in identifying cyclothymia. This study assessed the potential utility of the GBI in family and offspring studies by evaluating its ability to satisfy three prerequisites for use in such research: (1) identification of cyclothymia familially related to bipolar I disorder, (2) use with young adolescents, and (3) "insensitivity" to the effects of nonaffective psychopathology and parental nonaffective disorder in the offspring of control probands. The GBI and a blind, structured diagnostic interview were administered to 37 offspring of bipolar I patients and 21 offspring of psychiatric control patients, Twenty-seven percent of the offspring of bipolar patients, but none of the control offspring, were found to have bipolar forms of affective disorder, primarily cyclothymia (24%). Concordance between the GBI and interview-derived diagnoses was 95% to 97%, with 98% specificity and 80% to 90% sensitivity, depending on cutting score location. Together with the results of previous studies, the findings suggest that the GBI holds promise for the identification of cyclothymia in several research and clinical contexts.

A Critical Evaluation of Interlaboratory Data on Total, Elemental, and Isotopic Carbon in the Carbonaceous Particle Reference Material, NIST SRM 1649a.

Because of increased interest in the marine and atmospheric sciences in elemental carbon (EC), or black carbon (BC) or soot carbon (SC), and because of the difficulties in analyzing or even defining this pervasive component of particulate carbon, it has become quite important to have appropriate reference materials for intercomparison and quality control. The NIST "urban dust" Standard Reference Material(®) SRM 1649a is useful in this respect, in part because it comprises a considerable array of inorganic and organic species, and because it exhibits a large degree of ((14)C) isotopic heterogeneity, with biomass carbon source contributions ranging from about 2 % (essentially fossil aliphatic fraction) to about 32 % (polar fraction). A primary purpose of this report is to provide documentation for the new isotopic and chemical particulate carbon data for the most recent (31 Jan. 2001) SRM 1649a Certificate of Analysis. Supporting this is a critical review of underlying international intercomparison data and methodologies, provided by 18 teams of analytical experts from 11 institutions. Key results of the intercomparison are: (1) a new, Certified Value for total carbon (TC) in SRM 1649a; (2) (14)C Reference Values for total carbon and a number of organic species, including for the first time 8 individual PAHs; and (3) elemental carbon (EC) Information Values derived from 13 analytical methods applied to this component. Results for elemental carbon, which comprised a special focus of the intercomparison, were quite diverse, reflecting the confounding of methodological-matrix artifacts, and methods that tended to probe more or less refractory regions of this universal, but ill-defined product of incomplete combustion. Availability of both chemical and (14)C speciation data for SRM 1649a holds great promise for improved analytical insight through comparative analysis (e.g., fossil/biomass partition in EC compared to PAH), and through application of the principle of isotopic mass balance.

Schizotypal personality disorder in an outpatient population: incidence and clinical characteristics.

The incidence and clinical characteristics of DSM-III Schizotypal Personality Disorder (SPD) were explored in a series of 76 consecutive outpatients. Ten patients (13.2%) met DSM-III criteria for SPD. Patients with SPD were significantly more likely to receive a diagnosis of drug abuse or dependence and tended to exhibit a higher rate of major affective disorders than did the non-SPD group. Patients with SPD were rated as significantly more severely disturbed than non-SPD patients on the Global Assessment Scale for the current episode and the worst lifetime episode of disorder. In addition, SPD patients were significantly more likely to have histories of psychiatric hospitalization and attempted suicide and first received treatment at a significantly younger age than did non-SPD patients. These results indicate that SPD is relatively common in outpatient settings and is associated with particularly severe psychopathology.

Discriminant validity of the General Behavior Inventory: an outpatient study.

Recent studies have provided strong support for the convergent validity of the General Behavior Inventory (GBI), a case identification inventory for chronic subsyndromal affective disorders (cyclothymia and dysthymia). Fewer data are available, however, on the ability of the GBI to distinguish chronic subsyndromal affective disorders from other forms of psychopathology. In order to address this issue, outpatients with cyclothymia (n = 9), dysthymia (n = 26), nonchronic major depression (n = 16), and nonaffective psychiatric disorders (n = 30) were compared on the GBI. Diagnoses were derived blind to GBI scores using structured diagnostic interviews and DSM-III criteria. The inventory significantly discriminated cyclothymes and dysthymes from patients with nonchronic major depressions and nonaffective disorders. Using the cutoff score that maximized GBI-diagnosis concordance, the inventory correctly classified 88% of the sample. All of the cyclothymes, 92% of the dysthymes, 87% of the patients with nonaffective psychiatric disorders, and 75% of the nonchronic major depressives were correctly classified by the inventory. These data provide strong support for the discriminant validity of the GBI.