The Food and Drug Administration's panel of advisers voted 12-2 Tuesday in favor of an experimental drug from ACADIA Pharmaceuticals, saying its benefits outweigh the risks.

The panel’s vote is considered a recommendation for approval and is nonbinding, though the FDA often follows the advice of its panelists. ACADIA stock was up almost 24 percent in after-hours trading following the announcement.

“We are very encouraged by the Committee’s positive vote (Tuesday) and look forward to working with the FDA as it completes its review of Nuplazid,” said Steve Davis, ACADIA’s president and chief executive officer. “If approved by the FDA, Nuplazid would be the first drug indicated to treat psychosis associated with Parkinson’s disease.”

Earlier Tuesday, Nasdaq halted trading of ACADIA Pharmaceuticals’ stock as speculation regarding the regulatory review of clinical data spiked unusually high trading activity on Monday.

The San Diego drugmaker's stock was up nearly 20 percent on exceptionally high volume when trading was halted. The apparent catalyst behind the move was a positive note in the Food and Drug Administration’s briefing documents for ACADIA’s experimental Parkinson’s disease psychosis drug called Nuplazid, which was scheduled to be reviewed by a panel of outside experts Tuesday.

The spike underscores investor confidence despite a mixed-bag internal review of the medication released last week.

The company focuses on central nervous system (CNS) disorders and has a collaboration deal with Allergan focused on potential pain medications. Nuplazid is being tested on a variety of CNS diseases in clinical trials, including psychosis associated with Parkinson’s and Alzheimer’s.