Dihydrexidine, a novel full efficacy D1 dopamine receptor agonist. Dihydrexidine was shown to stimulate cyclic AMP synthesis just as well or better than dopamine. It was the first dopamine D1 receptor agonist that had potent antiparkinsonian activity in a primate model of Parkinson's disease. Dihydrexidine produces hypothermia. Dihydrexidine has been shown to alleviate cognitive deficits or enhance cognitive performance in a number of animal models of cognition. It is under investigation for the improving the cognitive and working memory deficits in schizophrenia and schizotypal disorder.