A better understanding of how the various symptoms of schizophrenia impact one another, and, as well, the ability of patients to function in society, could contribute to the development of more focused treatments that target specific functional deficits.

This was the concept that inspired a research team led by Samuel J. Abplanalp, Ph.D., of UCLA and the VA Healthcare System of Greater Los Angeles, to apply sophisticated forms of statistical and network analysis (“network psychometrics”) to wide-ranging data on 979 outpatients with schizophrenia or schizoaffective disorder. The results were published in JAMA Psychiatry. The subjects were recruited in research by the Consortium on the Genetics of Schizophrenia ( COGS),which focuses on the genetic underpinnings of schizophrenia and related issues in cognition and neurophysiology.

The team also included Michael F. Green, Ph.D., 2016 BBRF Lieber Prize winner; David L. Braff M.D., 2014 BBRF Lieber Prize winner and 2007 BBRF Distinguished Investigator; and Gregory A. Light, Ph.D., 2014 BBRF Baer Prize winner, 2013 BBRF Independent Investigator and 2006 and 2003 Young Investigator.

The researchers sought to discover boundaries as well as connections between the positive and negative symptoms of schizophrenia, on the one hand, and, on the other hand, what the team calls role functioning. Role functioning has to do with quality of life and involves such important activities as the capacity to socially engage, get along with family, and to hold a job.

The positive symptoms of schizophrenia refer to such things as hallucinations, delusions, and unusual thoughts. These are the symptoms that antipsychotic medicines help to control in many patients. Negative symptoms of the illness, in contrast, are difficult to treat and cannot be treated directly with current medicines. Negative symptoms include blunted affect, alogia (difficulty bringing thoughts to speech), avolition (reduced goal-directed activity due to decreased motivation), asociality (difficulty socializing), and anhedonia (reduced experience of pleasure).

Various forms of cognitive remediation have been used to treat people with schizophrenia. The impact can be very positive, but such treatments are difficult for many patients to access and can only be delivered by specially trained healthcare personnel.

In their multi-part analysis of data from the 979 outpatients, the team was able to show which schizophrenia symptoms tended to affect other symptoms, and which tended not to exert much influence on other symptoms. Similarly, the analysis was able to indicate mathematically which symptoms had the greatest impact on various aspects of function in daily life such as being social, being able to work, or being able to live independently.

Taking positive and negative symptoms into careful account across the 979 patients, the team was able to determine that anhedonia—the inability to experience pleasure, or the disinclination to seek pleasure—had the most connection with both positive and negative symptoms, as well as the ability to function in society.

The analysis also showed that positive symptoms had the weakest influence on negative symptoms or on the ability to function in the community. This finding does not mean positive symptoms are unimportant, only that they tend not to affect multiple other aspects of the illness.

In contrast, anhedonia had a notable impact on many other aspects of the illness, especially those related to how an individual is able—or unable—to function. The symptom of avolition—difficulty in initiating and persisting in self-directed, purposeful activities—was found to be strongly connected to certain functional areas, particularly the ability to work.

The team’s conclusion was that given the multiple impacts and centrality of anhedonia in the broad spectrum of schizophrenia symptoms, it might be a “viable target for schizophrenia interventions focused on multiple function areas,” the team said. In the same vein, they suggested that “avolition is a rational target for interventions focused on work functioning.”