Updated

(Note: explicit sexual content)

BELLEFONTE, Pennsylvania (Reuters) - A psychologist called by the defense in the Jerry Sandusky child sexual abuse trial testified on Tuesday that the former Penn State assistant football coach suffers from a personality disorder that is characterized by a deep need for attention and may lead to inappropriate, sexually seductive behavior.

Elliot Atkins, an important defense witness, told jurors he spent six hours interviewing the 68-year-old Sandusky, who is accused of sexually abusing 10 boys over a 15-year period.

"Based on my evaluation of Mr. Sandusky, I have diagnosed a histrionic personality disorder," Atkins said.

The psychologist's testimony followed attempts by defense lawyers earlier in the day to discredit the prosecution's case by suggesting investigators had coached testimony from one of the Sandusky's alleged victims.

Sandusky faces 51 counts of child molestation after the prosecution dropped one charge of unlawful contact with minors on Monday. If convicted on all counts, the former defensive coordinator for Pennsylvania State University's successful football program faces a sentence of more than 500 years in prison.

The case has focused renewed national attention on the issue of child sexual abuse and prompted the firing in November of Penn State President Graham Spanier and legendary head football coach Joe Paterno. Paterno died of lung cancer in January.

It was unclear whether Sandusky would testify as the trial entered its final stages. Asked as he arrived at court whether he would call his client to the witness stand, defense attorney Joe Amendola told reporters: "Stay tuned. Come on, it's like a soap (opera), you have to wait and see."

"Is it 'Days of Our Lives?'" a reporter asked in return, referring to a long-running U.S. daytime television drama.

"I think it's 'General Hospital,'" Amendola answered. Then, a moment later, after returning from parking his car, he said, "Actually it could be 'All My Children.'"

Amendola said previously that Sandusky would testify.

Eight alleged victims, now men aged 18 to 28, testified for the prosecution last week, describing in often graphic detail being molested by Sandusky as boys, including oral and anal sex and shared showers. Two other alleged victims have never been identified.

'CONFIRMED MY DIAGNOSIS'

Atkins told jurors that histrionic personality disorder is characterized by excessive emotionality and attention seeking, and symptoms include inappropriate sexually seductive or provocative behavior.

The psychologist testified that letters Sandusky wrote to one of his accusers - which prosecutors described as love letters - were consistent with his analysis. Sandusky's memoir, "Touched: The Jerry Sandusky Story," which was published in 2001, "absolutely confirmed my diagnosis," Elliot said.

Earlier in the day, defense lawyers took aim at law enforcement officers' testimony that they had not discussed abuse accounts offered by fellow accusers with other alleged victims in the closely watched case.

Amendola questioned Pennsylvania state trooper Corporal Scott Rossman and retired trooper Joseph Leiter about a taped interview they held with one of the accusers, known in court documents as Victim 4, and his attorney in April 2011.

The interview was played in court and Leiter was heard saying to Victim 4 during a break that investigators had interviewed about nine other potential victims. In some cases "oral sex has taken place by both parties," which would be considered rape under state law, he said.

Leiter could be heard saying telling the accuser that his story "word for word" followed those of others. "He has taken advantage of you. We need you to tell us what happened," Leiter is heard saying.

Under cross examination by a prosecutor, Leiter said he considered the interview technique to be appropriate and never suggested to a victim what he should say.

It was the second day of the defense case after the prosecution rested its case on Monday. Judge John Cleland told jurors on Monday he expected closing arguments to take place on Thursday.

Two university officials also face charges of perjury and failure to report suspected abuse in an alleged incident involving Sandusky and a boy at a Penn State locker room.

(Editing by Paul Thomasch and Will Dunham)