Scientists from St. Jude Children's Research Hospital said they have found a way to make schizophrenia patients' "voices in the head" be quieter. They studied the molecular mechanisms that disrupt the flow of information within neural circuits that connect brain centers, leading people to have auditory hallucinations.
The Team Identified Small RNAs That Could Be Potentially Targeted To Develop Antipsychotic Drugs
Using mice during the study, the research team mimics 22q11 deletion syndrome, also known as DiGeorge syndrome - a syndrome which makes individuals more likely to develop psychiatric conditions. They were able to identify small RNA sequences, or microRNAs, that could potentially be used in targeting for the development of antipsychotic drugs with minimal side effects.
The specific microRNA is called miR-338-3p, which regulates the manufacture of protein D2 dopamine receptor (Drd2) - a primary target of antipsychotics. The researchers found that as microRNA levels declined, levels of Drd2 increased in the auditory thalamus - a brain region associated with auditory hallucinations.
Author Dr. Stanislav Zakharenko said: "In 2014, we identified the specific circuit in the brain that is targeted by antipsychotic drugs. However, the existing antipsychotics also cause devastating side effects. In this study, we identified the microRNA that is a key player in disruption of that circuit and showed that depletion of the microRNA was necessary and sufficient to inhibit normal functioning of the circuit in the mouse model."
Scientists Found Clue As To Only Adults Tend To "Hear Voices"
Researchers also noted that microRNA levels declined with age in mice, whether or not they suffered from DiGeorge syndrome. "While miR-338-3p levels decline as normal mice age, levels may remain above the threshold necessary to prevent over-expression of the protein and hallucinations. In contrast, the deletion syndrome may leave mice at risk for dropping below that threshold," Zharenko said.
Scientists suggest to study the role of microRNA further to help develop more effective antipsychotic drugs.