What the general factor of psychological problems is-And is not.

Hundreds of published studies have advanced understanding of the hypothesized general factor of psychological problems, but confusion still surrounds the hypothesis. This partly results from critics conflating our hypotheses with those of other authors, but we have created confusion ourselves by stating two different general factor hypotheses, which we differentiate here. In the psychometric general factor hypothesis, the general factor is the term in bifactor models that quantifies the variance shared by all measured psychological problems, whereas two or more specific factors are defined by orthogonal pools of variance shared only by items loading on each specific factor. Although the psychometric bifactor model is sometimes viewed as an alternative to taxonomic models based on correlated factor models, it is not. Correlated factors models properly describe the overlapping dimensions of psychological problems experienced in everyday life. The separate hierarchical causal hypothesis is that correlations among the problems that define the general factor result from some of their causes and mechanisms being directly or indirectly shared, whereas the specific factors are the result of other orthogonal causes being shared by subsets of problems. There is growing evidence that some genetic and environmental causes-and their attendant psychobiological mechanisms-are shared to varying degrees with essentially all psychological problems. Other independent causes and mechanisms influence only subgroups of psychological problems (e.g., internalizing problems). (PsycInfo Database Record (c) 2025 APA, all rights reserved).