The Hierarchical Taxonomy of Psychopathology (HiTOP) has emerged out of the quantitative approach to psychiatric nosology. This approach identifies psychopathology constructs based on patterns of co-variation among signs and symptoms. The initial HiTOP model, which was published in 2017, is based on a large literature that spans decades of research. HiTOP is a living model that undergoes revision as new data become available. Here we discuss advantages and practical considerations of using this system in psychiatric practice and research. We especially highlight limitations of HiTOP and ongoing efforts to address them. We describe differences and similarities between HiTOP and existing diagnostic systems. Next, we review the types of evidence that informed development of HiTOP, including populations in which it has been studied and data on its validity. The paper also describes how HiTOP can facilitate research on genetic and environmental causes of psychopathology as well as the search for neurobiologic mechanisms and novel treatments. Furthermore, we consider implications for public health programs and prevention of mental disorders. We also review data on clinical utility and illustrate clinical application of HiTOP. Importantly, the model is based on measures and practices that are already used widely in clinical settings. HiTOP offers a way to organize and formalize these techniques. This model already can contribute to progress in psychiatry and complement traditional nosologies. Moreover, HiTOP seeks to facilitate research on linkages between phenotypes and biological processes, which may enable construction of a system that encompasses both biomarkers and precise clinical description.

Background. The categorical classification system for personality disorder (PD) has been frequently criticized and several alternative dimensional models have been proposed.

Method. Antecedent, concurrent and predictive markers of construct validity were examined for three models of PDs: the Five-Factor Model (FFM), the Schedule for Nonadaptive and Adaptive Personality (SNAP) model and the DSM-IV in the Collaborative Study of Personality Disorders (CLPS) sample.

Results. All models showed substantial validity across a variety of marker variables over time. Dimensional models (including dimensionalized DSM-IV) consistently outperformed the conventional categorical diagnosis in predicting external variables, such as subsequent suicidal gestures and hospitalizations. FFM facets failed to improve upon the validity of higher-order factors upon cross-validation. Data demonstrated the importance of both stable trait and dynamic psychopathological influences in predicting external criteria over time.

Conclusions. The results support a dimensional representation of PDs that assesses both stable traits and dynamic processes.

Background. A defining feature of personality disorder (PD) is an enduring pattern of inner experience and behavior that is stable over time. Follow-up and follow-along studies have shown considerable diagnostic instability of PDs, however, even over short intervals. What, then, about personality disorder is stable? The purpose of this study was to determine the stability of impairment in psychosocial functioning in patients with four different PDs, in contrast to patients with major depressive disorder (MDD) and no PD, prospectively over a 2-year period.

Method. Six hundred treatment-seeking or treated patients were recruited primarily from clinical services in four metropolitan areas of the Northeastern USA. Patients were assigned to one of five diagnostic groups: schizotypal (STPD) (n=81), borderline (BPD) (n=155), avoidant (AVPD) (n=137), or obsessive–compulsive (OCPD) (n=142) personality disorders or MDD and no PD (n=85), based on the results of semi-structured interview assessments and self-report measures. Impairment in psychosocial functioning was measured using the Longitudinal Interval Follow-up Evaluation (LIFE) at baseline and at three follow-up assessments.

Results. Significant improvement in psychosocial functioning occurred in only three of seven domains of functioning and was largely the result of improvements in the MDD and no PD group. Patients with BPD or OCPD showed no improvement in functioning overall, but patients with BPD who experienced change in personality psychopathology showed some improvement in functioning. Impairment in social relationships appeared most stable in patients with PDs.

Conclusion. Impairment in functioning, especially social functioning, may be an enduring component of personality disorder.

The rate of DSM-III schizotypal personality traits was evaluated in three groups of adolescent offspring (ages 15–21), defined by the psychiatric diagnosis of their parents. Parental diagnoses included schizophrenic disorder (40 adolescents), affective disorder (35 adolescents), and ‘no psychiatric disorder’ (normal controls) parents (82 adolescents). The presence of the eight component features of schizotypal personality disorder was assessed from video-taped semi-structured psychiatric interviews, subsequently rated by trained psychiatrists, blind to the parental psychiatric status of the subjects. The effect of age, sex, and social class on the pattern of prevalence results was examined.

The expected specificity of DSM-III schizotypal personality traits to schizophrenia was not supported by the prevalence pattern of the traits. Rates of 2 or more, 3 or more, and 4 or more schizotypal personality features were highest in the parental psychiatric groups. The rates of schizotypal personality traits in adolescent offspring of affective disorder parents were as high as those previously reported for relatives of schizophrenic disorder probands.