A Transdiagnostic Review of Negative Symptom Phenomenology and Etiology

Abstract

In the DSM5, negative symptoms are 1 of the 5 core dimensions of psychopathology evaluated for schizophrenia. However, negative symptoms are not pathognomonic-they are also part of the diagnostic criteria for other schizophrenia-spectrum disorders, disorders that sometimes have comorbid psychosis, diagnoses not in the schizophrenia-spectrum, and the general "nonclinical" population. Although etiological models of negative symptoms have been developed for chronic schizophrenia, there has been little attention given to whether these models have transdiagnostic applicability. In the current review, we examine areas of commonality and divergence in the clinical presentation and etiology of negative symptoms across diagnostic categories. It was concluded that negative symptoms are relatively frequent across diagnostic categories, but individual disorders may differ in whether their negative symptoms are persistent/transient or primary/secondary. Evidence for separate dimensions of volitional and expressive symptoms exists, and there may be multiple mechanistic pathways to the same symptom phenomenon among DSM-5 disorders within and outside the schizophrenia-spectrum (ie, equifinality). Evidence for a novel transdiagnostic etiological model is presented based on the Research Domain Criteria (RDoC) constructs, which proposes the existence of 2 such pathways-a hedonic pathway and a cognitive pathway-that can both lead to expressive or volitional symptoms. To facilitate treatment breakthroughs, future transdiagnostic studies on negative symptoms are warranted that explore mechanisms underlying volitional and expressive pathology.

Keywords: alogia; anhedonia; asociality; avolition; blunted affect.

Fig. 1.

Visual representation of negative symptoms throughout DSM-5 diagnoses. Note: Bracketed numbers correspond with diagnoses listed in table 2 (see numbers in far left column). Text included in figure represents excerpted or paraphrased material from DSM-5 diagnostic criteria or associated features supporting diagnoses. Information is organized graphically in relation to the 5 domains of negative symptoms identified in the 2005 NIMH Consensus Conference. The figure illustrates the wide range of terminology used to describe negative symptom phenomenon, as well as conceptual overlap of terminology (text in overlapping circles) and conflation of constructs.

Fig. 2.

Transdiagnostic quantitative comparison of the 2 negative symptom dimensions and 5 consensus domains on the SANS. Note: Panels A and B represent frequency distributions of SANS scores on the expressive and volitional dimensions, respectively. Y-axis values reflect cumulative percentages of participants and X-axis scores denote the average SANS dimension score calculated by adding the 2 global items in each factor and dividing by 2. Exp, expression dimension; VOL, volitional dimension; Anhed/Asoc, global anhedonia/asociality item. Panels C and D reflect Z-scores for each group compared to healthy controls and schizophrenia patients, respectively. As can be seen in Panels A and B, there is variability in scores within each group, but both dimensions tend to be positively skewed. Z-scores indicated a continuum of severity scores ranging from: schizophrenia > ultra high-risk > schizoaffective >major depression > bipolar disorder > healthy control.

Fig. 3.

Graphical representation of the NIMH RDoC positive valence system constructs. Note: Figure depicts our representation of how RDoC positive valence system constructs are hierarchically organized and how they might interact with one another. This figure was not developed or endorsed by NIMH.

Fig. 4.

Transdiagnostic equifinality model of negative symptoms. Note: Higher-order cognitive control deficits are defined here as processes that allow information processing and behavior to adaptively adjust from moment-to-moment in response to current goals, facilitating a broad range of cognitive processes such as working memory, attention, long-term memory, emotion processing, and reward processing.