Dream narratives can help diagnose schizophrenia

Researchers use graph theory to analyze patient speech and help diagnose schizophrenia earlier.

By Elton Alisson, in Maceió  |  Agência FAPESP – Schizophrenic patients may suffer from psychosis, a loss of contact with reality that causes delusions, hallucinations and incoherent speech, among other symptoms. However, it can take six months to diagnose these patients conclusively, and the diagnosis may be revised several times during their lifetime by different specialists, since there are no clinically useful biomarkers of schizophrenia.

“Today, what’s measured to diagnose schizophrenia is the patient’s answers to a questionnaire. Although this method is important, it’s highly subjective. As a result, patients with schizophrenia are treated in different ways by multiple methods, and usually with a combination of drugs,” said Sidarta Ribeiro, a neuroscientist and head of the Brain Institute at the Federal University of Rio Grande do Norte (UFRN) in Natal, Brazil.

In the last ten years, Ribeiro has collaborated with colleagues at his laboratory and other institutions in Brazil and abroad on a series of studies designed to analyze the speech of patients with schizophrenia mathematically and seek correlations with their symptoms.

Some of the findings produced by these studies were outlined by Ribeiro in a presentation delivered on July 26, 2018, at the 70th Annual Meeting of the Brazilian Society for the Advancement of Science (SBPC), held at the Federal University of Alagoas (UFAL) in Maceió.

“The idea behind these studies is to develop a method for the early diagnosis of schizophrenia so that patients can receive suitable treatment sooner, because the damage done by psychotic breaks is cumulative,” Ribeiro said. 

“The first psychotic episode causes some cognitive impairment, the next does more damage, and so on. Inadequate treatment of these patients can result in the persistence of their current problems and the development of other problems.”

The symptoms of patients with psychosis are fairly self-evident, he added. If chronic cases with a succession of psychotic breaks are not treated properly, they can lead to disorganized speech known as “word salad”, a confused or unintelligible mixture of seemingly random words and phrases.

The researchers use graphs as a mathematical method of analyzing patients diagnosed with psychotic symptoms as they talk about their dreams, in an effort to identify the mental disorder concerned more accurately.

Classified as the “royal road to the unconscious” by Sigmund Freud (1856-1939) in his 1899 essay on The Interpretation of Dreams, dreams are a key element of psychoanalysis and have also proven relevant to the clinical diagnosis of schizophrenia by psychiatrists, according to Ribeiro. “We’ve found dream narratives to be particularly useful in clinical psychiatry,” he said.

Differences between dream narratives

The researchers recorded the dream narratives of 60 volunteer patients for a study conducted in collaboration with colleagues at the Physics Department of the Federal University of Pernambuco (UFPE) and the Research, Innovation and Dissemination Center for Neuromathematics (NeuroMat), one of the Research, Innovation and Dissemination Centers (RIDCs) funded by FAPESP. The recordings were made with the consent of the volunteers, who were being treated at the psychiatry outpatient clinic of a public hospital in Natal, Rio Grande do Norte.

Some of the patients had been diagnosed with schizophrenia and others with bipolar disorder. The rest, who comprised the control group, had no symptoms of mental disorders. 

The patients’ dream narratives were transcribed, and speech samples were converted into graphs using software developed by Brain Institute researchers. Analysis of the graphs derived from the dream narratives showed clear differences among the three groups of patients. 

The graphs for patients diagnosed with schizophrenia or bipolar disorder and for the controls without mental disorders differed in size, the numbers of edges or links, and the relationships between nodes.

“The schizophrenics’ dream narratives were extremely laconic, whereas those of patients with bipolar disorder were more disjointed and rambling. The controls were chronological and relatively coherent. The method can be used to map patients’ minds via words,” Ribeiro said.

In another study that has yet to be published, the researchers recorded dream narratives by adolescents who had experienced a first psychotic episode, as well as their accounts of positive, negative and neutral memories of the previous day and the more distant past. The aim was to determine the best basis for forecasting a diagnosis of schizophrenia six months later. Dream narratives outperformed the rest.

“We had hypothesized that memories of the more distant past resembled dreams, but this wasn’t what we found. Dreams classified schizophrenic patients best and were more suited to predicting a diagnosis of schizophrenia after six months,” Ribeiro said.