Researchers reported negative results from the first repeated-dose study of a dopamine-1 receptor (D1R) agonist for treating cognitive and negative symptoms of schizophrenia.Based on earlier preclinical research suggesting that reduced signaling through the D1R might contribute to these symptoms, scientists speculated that administering ultra-low doses of D1R agonists might counteract these symptoms. For over a decade, researchers have sought to reproduce comparable results in clinical studies, with mixed findings and no definitive answers.

Source: Disproving hypothesis clears path for research for new treatment options for schizophrenia