A young woman found dead at the bottom of a garbage chute in a luxury Melbourne apartment was deeply troubled and had a problem with alcohol, an inquest has heard.

Antony Hampel said his girlfriend Phoebe Handsjuk, 24, had been drinking and had missed work in the days before she fell 12 floors to her death in December 2010.

Ms Handsjuk had battled depression and struggled with drugs and alcohol the whole time Mr Hampel knew her, he told the Victorian Coroners Court.

"Sometimes she would cut herself," he said in a statement.

"It was a cry for help. She never did this when sober."

He said Ms Handsjuk would binge drink, causing her personality to "shift".

"Aggression or anger would start to come up the more she drank," he said.

He told the court a mutual friend had told him Phoebe said she was thinking of killing herself.

"She told Vanessa she was thinking of jumping off the balcony," Mr Hampel said.

He described her behaviour as becoming more "erratic" after September 2010, when the dosage of her medication prescribed by her psychologist was changed.

He said he believed Ms Handsjuk committed suicide.

Police found Ms Handsjuk had committed suicide but the inquest has been asked to determine if the death was accidental or if another person was involved.

Her family has questioned the competence of the police investigation.

Her mother's partner Russell Marriott previously told the inquest there was "absolutely not" any way Ms Handsjuk could have killed herself.

Ms Handsjuk's grandfather, a retired detective, said it was absurd that an intoxicated person would have been able to climb into the garbage hatch, the top of which was a metre off the ground.

On the night of Ms Handsjuk's death, Mr Hampel came home to their apartment to find there was a shrine of photos, candles and notes on their bed but Phoebe was gone.

A post-mortem examination found traces of alcohol, prescription medication and the sleeping pill Stilnox in Ms Handsjuk's blood.

The inquest continues.

* Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or Suicide Call Back Service 1300 659 467.