Functional connectivity appears to be lower in the part of the brain associated with decreased volition in first-episode neuroleptic-treated patients with schizophrenia, a study suggests.
“An implication is that treatments that increase this connectivity, such as treatments that restore the hypoglutamatergia of schizophrenia, might treat these symptoms,” wrote Weidan Pu, Ph.D., and his research team.
Dr. Pu and his associates recruited 22 first-episode neuroleptic naive schizophrenia patients, 61 first-episode neuroleptic-treated schizophrenia patients, and 60 healthy controls. Their goal was to identify neurophysiological deficits present in schizophrenia that are resistant to antipsychotics, reported Dr. Pu of the Institute of Mental Health, Second Xiangya Hospital in Changsha, China.
Using fMRI, the researchers found more strengthened functional connections in the untreated patient group than in the group that received the neuroleptics. An additional difference between the two groups was that abnormal interhemispheric connectivity was more widespread and weakened in the patients who had been treated with neuroleptics.
Other differences between the two groups of schizophrenia patients were found in 10 subscale scores of the Positive and Negative Symptoms Scale (PANSS). On average, the untreated patients scored significantly higher in areas including delusion, hostility, stereotyped thinking, anxiety, tension, poor impulse control, preoccupation, and uncooperativeness.
A similarity between the groups is that they both experienced reductions in functional connectivity between the posterior cingulate gyrus (PCG) and precuneus (PCUN). Because the study also determined that this circuit changed commonly in both sets of patients, “it may be inferred that the reduced functional connectivity between PCG and PCUN … has extended previous evidence that the functional deficits in the PCG-PCUN circuit are not only critical in the pathophysiology of schizophrenia, but also are possibly resistant to neuroleptic drugs,” Dr. Pu and his colleagues wrote.
Among the study’s other findings was a correlation between the weakened PCG-PCUN circuit and reduced volition.
“[T]hese common brain alterations in [both groups of patients], in combination with their associations with volitional deficits and negative symptoms, suggest current pharmacological treatment may have less efficiency on the volitional deficits and negative symptoms, and their related neurophysiological deficits in the schizophrenia patients,” the researchers wrote.
Find the full study in NeuroImage: Clinical ( doi: 10.1016/j.nicl.2014.10.004 ).
