Schizophrenia and bipolar disorder are serious mental illnesses that affect both males and females, but research in Acta Psychiatrica Scandinavica indicates that sex may influence the characteristics and course of these conditions.

The research included 1,516 individuals from the multicenter PsyCourse Study: 543 with bipolar disorder, 517 with schizophrenia, and 456 healthy controls.

Several differences between groups and sexes were identified in age at diagnosis, age at treatment, illness duration, illicit drug use, and smoking. For example, females in the schizophrenia group were older than males at first outpatient treatment, compared with females in the bipolar disorder group. Moreover, those who were older at first outpatient treatment presented a longer duration of illness.

Regarding substance use, the highest rates were observed in males with schizophrenia. People with bipolar disorder showed better functioning and neurocognitive performance than those with schizophrenia. Among individuals with bipolar disorder, females reported better performance in verbal memory and psychomotor speed than males. Both females and males with serious mental illnesses showed higher rates of thyroid alterations than healthy controls.

“Our findings reveal a clear message: sex-sensitive treatment is essential for improving clinical outcomes, promoting healthy habits, and managing comorbidities,” said corresponding author Anabel Martinez-Arán, Ph.D., of the Hospital Clinic of Barcelona.