Women, Men With Schizophrenia Interpret Others' Emotions Differently

Deborah Brauser

November 02, 2018

There are significant sex-based differences in both healthy individuals and those with schizophrenia in the way they identify the intentions and the mental state of others, including beliefs, desires, and emotions, new research suggests.

Dr Dolores Malaspina

A study of almost 70 participants showed that the participants with schizophrenia were significantly impaired in their ability to identify the mental state and to infer intentions of people shown in photographs compared with a group of their healthy peers.

Further analyses showed that in the subgroup of healthy women, there was a significant association between higher intelligence/cognition and mental state identification and inferring intentions in others, whereas in the subgroup of healthy men, there was a significant correlation between better smell identification/affective influences and mental state identification in others.

These patterns were opposite in those who had schizophrenia. For women with this condition, there was a strong link between better smell detection and mental state identification, whereas for men with the condition, there was a greater link between higher intelligence and mental state identification and inferring intentions.

The findings suggest that the "cognitive influences in healthy females and affective influences in healthy males are reversed in schizophrenia and may be displaced to lower circuitries by disease pathology," the investigators write.

"In schizophrenia, the inability to know what other people intend to do or what other people feel is a very important deficit," senior author Dolores Malaspina, MD, director of the Psychosis Program and professor of psychiatry and neuroscience, Icahn School of Medicine at Mount Sinai, New York City, told Medscape Medical News.

"If you don't know about a person's intentions, you might be paranoid about what they're up to, or you might not read them correctly and feel hurt or angry," said Malaspina.

"There is now hope that we can improve the outcome for people with schizophrenia by teaching them how to better read social signals and understanding the impact of different treatments on social functioning. And those studies really should be sex stratified," she said.

The findings were published online October 30 in the Social Neuroscience.

Theory of Mind

"The ability to mentalize, or theory of mind (ToM), is sexually dimorphic in humans and impaired in schizophrenia," the investigators write. "This sex-stratified study probed cognitive (indexed by intelligence) and affective (indexed by olfactory tasks) contributions to ToM performance," they add.

"Many times people do research in psychiatric disease, and they put males and females together as one large group. But the fact is, male and female brains really are different," Malaspina said. "So we were looking at two things that had sex differences. In the disease schizophrenia, females typically have better outcomes than males in many ways. We also looked at the ability to read social cues in theory of mind."

The researchers enrolled 37 "clinically stable" patients with schizophrenia or schizoaffective disorder (64% men) and 31 individuals to act as the healthy control group (45% men).

The Positive and Negative Syndrome Scale (PANSS) was used to measure symptom severity in those with a psychiatric disorder.

The Reading the Mind in the Eyes test (RME) was used to help identify another individual's mental state. All participants were shown 36 pairs of eyes in photos and were asked to perform a nonaffective control task: identify the person's sex.

They were also asked to choose one of four possible complex mental states for the persons in the photos, such as "playful" or "confused." This task was used to measure emotion decoding's reflexive process.

To assess the participants' ability to infer the intentions of others by way of reasoning, the investigators used the Strange Stories Task (SST). Each study-group member was asked to read 12 vignettes, report the meaning of what a particular character said, and then give a reason/justification for their response.

The vignettes "featured a main character speaking sarcastically or ironically," the researcher report.

Other measurements included the Smell Threshold Test, the University of Pennsylvania Smell Identification Test, and the Full Scale Intelligence Quotient (FSIQ) on the Wechsler Adult Intelligence Scale, Third Edition.

"Intelligence scores measured more complex brain processing and olfactory or scent scores measured simpler mental processing," the investigators noted in a press release.

"Sense of smell is the most ancient way of detecting what others are up to, but its relationship to social processes has been unclear," added Malaspina.

First Study of Its Kind

Results showed that the patients with schizophrenia had worse scores than the healthy control group on the RME mental state identification task (P = .04) and on SST inferring intentions (P = .013) and justification (P = .039) measures.

There were no between-group difference in RME sex identification scores.

In men with schizophrenia and women in the control group, higher intelligence, as measured on the FSIQ, was significantly associated with more accurate mental state identification (P = .001 and .004, respectively) and with inferring intentions on the SST (P = .002 and .036).

In women with schizophrenia and men in the control group, more accurate mental state identification was significantly associated with better smell identification (P = .041 and .035, respectively).

In addition, greater negative symptom severity scores on the PANSS was significantly linked with lower smell identification scores in the men with schizophrenia (P < .001), whereas higher positive symptom severity was linked with lower smell detection scores in the women with schizophrenia (P < .05).

"Males appear to rely on limbic processing for ToM, and disruption to this circuitry may contribute to development of negative symptoms," write the investigators.

They add that this is "the first study to consider sex differences in the neural underpinnings of mentalizing in schizophrenia."

Window on Schizophrenia

"The neurocircuitry of olfaction is very closely related to the neurocircuitry for emotional processing. So the interaction between the two might be a window to better understanding schizophrenia," lead author Julie Walsh-Messinger, PhD, assistant professor at the University of Dayton, Ohio, said in a press release.

"Women and men are fundamentally different, and it is critical to perform sex-specific research across psychiatry and all of medicine," Malaspina added in the same release.

"Sex-stratified research is essential for studying the social processes in general and especially for conditions such as schizophrenia that present differently in women and men," she said.

She noted to Medscape Medical News that "even though the disease gene might be the same in males and females, it's interacting with different brain machinery."

The study was funded by grants from the National Institute of Mental Health. The study authors have reported no relevant financial relationships.

Soc Neurosci. Published online October 30, 2018. Abstract

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