When John Mullarkey took the acne medication Accutane, he never reported depression or any other psychological side effects, according to a physician's assistant who treated him.

Dayna Turrill, of Allegheny Dermatology Associates, testified this morning at Mr. Mullarkey's homicide trial. The 20-year-old Monroeville man is charged with killing his on-and-off girlfriend Demi Cuccia, 16, a Gateway High School cheerleader.

Attempting to avoid a first-degree murder conviction, Mr. Mullarkey's defense is claiming he was unable to form the intent to kill because of depression partially caused by Accutane.

But Ms. Turrill, a prosecution rebuttal witness, said that after initial problems with headaches, Mr. Mullarkey's dosage was cut in half and he seemed fine.

Mr. Mullarkey started treatment in April 2007 and by June, reports note he was "clear and happy," as the medicine successfully treated his persistent acne. On Aug. 15, he stabbed Demi to death and cut his own throat in an apparent suicide attempt.

Deputy District Attorney Mark V. Tranquilli also presented Mark Seraly, a Peters dermatologist, to testify about the side effects of Accutane. Dr. Seraly, who said he has treated 3,000 patients with Accutane over 15 years, praised Accutane as a "miracle drug."

Dr. Seraly called reports that patients suffered depression or committed suicide while on the medication scattered and unscientific.

"There is so much myth and misperception attached to this medication that is clearly not based on what we've observed over 27 years," Dr. Seraly said. The dermatologist quoted research that Accutane patients actually commit suicide at one fourth the rate of the rest of their age group.

During cross-examination, defense attorney Robert E. Stewart brought up FDA warnings of depression or suicide, which Dr. Seraly claimed were prompted by unscientific reporting methods and were a symptom of over-caution and fear of litigation.

"This is an extremely safe medication," Dr. Seraly said. "It's gotten on the radar for a variety of media-related events."

Testimony is scheduled to conclude this afternoon with the final prosecution rebuttal witness, Bruce Wright, a psychiatrist who examined Mr. Mullarkey.