The doctor who performed the psychological evaluation on Allyson McConnell testified during her second-degree murder trial Tuesday.

Psychiatrist Dr. Alberto Choy testified on the dramatic change from a seemingly happy wife and mother, to a withdrawn and depressed woman, saying:

"While it's not out of the realm of possibility that she lost the intent to kill her children…It is much more likely the death of her children was purposeful, in that she wanted to keep her children with her when she made the decision she did not want to continue with her life."

Choy also said he didn't think her memory difficulties are deliberate.

The forensic psychologist told court her amnesia is "her way of coping with various trauma in her life -- have included shutting down especially shutting down emotion even memories. It's her way of coping with life."

He described the case as complicated, calling McConnell intelligent, capable and fit to stand trial.

He told court the McConnell's bitter divorce combined with sleep deprivation from taking care of two children put pressure on the accused, and she began to drink to ‘take the edge off'.

Dr. Choy's testimony comes a day after the accused took the stand; in her emotional testimony she said Monday she didn't remember drowning the boys.

McConnell's two sons had been drowned in the bathtub of their family home in Millet back in February of 2010.

The accused has since admitted she drowned her sons but has pleaded not guilty to the two second-degree murder charges laid against her.

On Monday, McConnell spoke about the erosion of her marriage, saying by December 2009, her husband, Curtis McConnell, had moved out and barred her from contacting his parents.

She said on the stand that in the weeks leading up to her sons' deaths, the situation had continued to escalate - with tense e-mails exchanged between the two of them.

In her testimony, she also referred to suicidal thoughts that dated back to her teenage years, starting when she became pregnant by her father at 15-years-old – a baby lost in a miscarriage.

McConnell's lawyer, Peter Royal, asked his client Monday why she would want to kill herself.

"Because I thought my life wasn't worth living," she said.

On the day her two boys were found drowned, McConnell apparently tried to kill herself by jumping off an overpass over Whitemud Drive.

It will be up to the judge to determine whether McConnell had the intent or frame of mind to commit murder as she has already admitted to killing the children.

With files from Serena Mah