NEW YORK (TheStreet) -- ACADIA Pharmaceuticals (ACAD - Get Report) stock is declining 2.82% to $31.39 on heavy trading volume on Monday morning even though the FDA approved Nuplazid to treat hallucinations and delusions related to Parkinson's disease psychosis. The San Diego-based biopharmaceutical company announced the approval on Friday after the market close.

"Nuplazid represents the culmination of many years of work across our entire organization to bring this novel medicine, discovered by our scientists, to patients in need," CEO Steve Davis said in a statement.

JPMorgan analysts said in a note that the treatment could be "a potential blockbuster drug" because it is the only drug labeled specifically for Parkinson's disease psychosis with a substantial target population.

"We nevertheless assume a gradual launch that takes time to hit its stride (we currently model ~$8M in 2016 sales)," analysts explained. "Looking ahead, we are anticipating something of a tug of war between investors focusing on the launch, the scarcity value (ACAD owns 100% of Nuplazid's WW rights), and the pending randomized Phase 2 ADP data in late 2016e."

So far today, 4.24 million shares of ACADIA Pharmaceuticals have exchanged hands, compared with its average daily volume of 3.07 million shares.

Separately, ACADIA Pharmaceuticals has a "sell" rating and a letter grade of D at TheStreet Ratings because of the company's feeble earnings per share growth, deteriorating net income, disappointing return on equity, weak operating cash flow and generally disappointing stock performance.

You can view the full analysis from the report here: ACAD

TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this article's author.