LAWRENCE, Mass. (Court TV) — A "perfect storm" of external and internal forces led Richard Sharpe to gun down his estranged wife without understanding his actions, a psychiatrist testified Monday in the cross-dressing dermatologist's murder trial.

"I believe he was in a dissociative state, out of contact with reality, not able to function as himself in the setting of these multiple medications, alcohol and his underlying mental disorders," defense expert Dr. Keith Ablow told jurors.

He said a host of circumstances, including Sharpe's toxic mix of prescription drugs and wine on the night of the shooting, his unusual access to a gun, and Karen Sharpe's decision to leave the 26-year marriage combined with the doctor's severe psychiatric problems to create "a kind of perfect storm of things that would impair this man's capacity to control his behavior in any meaningful way."

Ablow's reference to the Sebastian Junger best-seller "A Perfect Storm," the chronicle of a massive and deadly storm created by rare meteorological conditions, was not lost on jurors from the north shore of Massachusetts. Before his arrest, Sharpe, 47, made millions in business ventures and a dermatology practice in the seaside city of Gloucester, the setting for the book.

But literary references aside, it was unclear how persuasive jurors found Ablow. Most of the panel paid close attention to the expert's testimony, including his explanation of Sharpe's affinity for high heels and fishnet stockings, but as with the defendant's testimony last week, a couple of jurors began staring at the floor as the day wore on. If jurors reject his insanity defense, Sharpe faces life in prison without parole.

When he testified, Sharpe admitted shooting the mother of his three children in the chest on July 14, 2000, but he said the killing was a "blur." He said a vague desire to get his family back led him to steal a gun and go to his wife's new home, but he claimed to have no idea why he shot her.

Prosecutor Robert Weiner maintains Karen Sharpe's death was the culmination of years of abuse by her husband. On the night of the killing, the prosecutor claims, Sharpe believed she had stolen some $3 million from him and was having an affair with the contractor working on the couple's "dream home."

Ablow, hired at a cost of more than $6,000, said that long before the shooting the doctor began suffering from several mental problems, including major depression, narcissism and intermittent explosive disorder, which he described as "an impulse control disorder." He noted that Karen Sharpe had her husband committed for several days in 1991 after he attacked her with a fork.

The night of the shooting, he said, his problems were exacerbated by heavy drinking, a head injury he had suffered several months before, and the dawning reality that his wife was not returning to the marriage.

"Dr. Sharpe lacked the ability to conform his behavior to the requirements of the law and very likely could not tell right from wrong when he killed his wife on July 14, 2000," Ablow said.

The doctor's mental problems stemmed from "catastrophic abuse" at the hands of his father, according to Ablow. He said the first sign was probably Sharpe's habit of dressing up in the clothes of his younger sister, Lauri, who was her father's favorite child and only daughter.

"When his father was raging and drunk, Dr. Sharpe would hide in his sister's room dressed as a girl," Ablow said. Sharpe's reasoning, he said, was "maybe if I'm kind of like her, I'll escape this kind of torture."

He said that Sharpe had a lifelong obsession with trying to appear normal, and when, as a high school junior, he met Karen Hatfield, she became "his lifeline to normality."

He said Sharpe believed his wife was the only thing standing in the way of his "utter disintegration as a person" and became unhinged whenever he thought she was leaving him.

In a slow cross-examination of Ablow, prosecutor Weiner got the psychiatrist to admit that the defendant was a master manipulator who showed some consciousness of guilt immediately after the shooting by disposing of the gun.

The prosecutor also shed new light on his theory of the murder weapon, which has never been recovered. Ballistic evidence indicates Karen Sharpe died from a .22-caliber gun, but Sharpe claims that the night of the shooting he took an acquaintance's weapon. That acquaintance, Alden Tarr Sr., however, testified the missing gun was a .30-caliber, not a .22.

As he questioned Ablow Monday, Weiner suggested the doctor got a .22-caliber long before the killing and then took the .30 "so that he could make it look like the shooting was a spur of the moment thing."

The prosecutor also ridiculed Sharpe's jailhouse hanging attempt as feeble and no proof of preexisting mental illness.

It happened, he said, "after he had shot Karen Sharpe, after he had been arrested, after his world had collapsed on him."

Testimony in the case is to conclude Tuesday.