A young mum who took cannabis and magic mushrooms to fight morning sickness killed herself by stepping in front of a train after developing serious mental problems, an inquest heard.

Polly Ross, 32, died after telling staff at a psychiatric unit in Hull, East Yorkshire, she was going to buy cigarettes in July 2015.

But hours later the mother of two daughters was struck by the 11.10am Hull-to-Scarborough train, killing her instantly, Hull Coroners Court was told yesterday (8 October).

Ross had tried to take her own life herself three times before, and suffered from postnatal depression following both her pregnancies in 2012 and 2014.

She also suffered from hyperemesis gravidarum (HG) during her pregnancies, an extreme form of morning sickness, which can cause severe vomiting, dehydration and weight loss. This condition has affected the Duchess of Cambridge during the current pregnancy of her third child.

The coroner, Professor Paul Marks, heard that Ross had fallen into a "drug induced psychosis" after taking recreational drugs to ease her postnatal depression.

The young mum's GP, Dr Daniella Malesknasr, told the hearing: "She had told me when she was pregnant with her second child that she was taking cannabis and magic mushrooms to help combat HG during her pregnancy – but she was no longer taking it," reported MailOnline.

The coroner asked: "And does taking cannabis actual benefit those suffering from HG?"

The doctor replied: "I can't possibly comment on that."

Anti-depressants and therapy

The hearing was told that Ross had run a translation business in Paris where she met her English husband Samuel Ross in 2011. The pair quickly married and had two children.

But the couple became estranged over a number of years, and the young mum moved to East Yorkshire in August 2012 to be closer to her mother.

Ross first went to her GP Dr Malesknasr for help with depression in August 2014, not long after the birth of her second daughter. She was prescribed anti-depressants and therapy.

But her condition had declined by February 2015, when she first confessed to Dr Malesknasr she harboured suicidal thoughts.

Ross' mother Jo Hogg, an occupational therapist, contacted Dr Malesknasr in February and raised concerns about the amount of cannabis and magic mushrooms her daughter was taking.

The young mother was sectioned and discharged from local mental health units a number of times between March and July. During that period she slashed her wrists and took two drug overdoses.

On 10 July, she was a voluntary patient at the Westlands mental health unit in Hull. She told nurses at 8.30am that she was going out to buy cigarettes, but was not seen alive again.

A statement read to the court by Ross's aunt Emma May, who acted as her carer after she was first sectioned, read: "I feel that Polly was desperately ill and was unable to make decisions for her own safety and well-being. I cannot understand how she was allowed to leave the unit to buy her own cigarettes the morning she died."

Hogg told the inquest that her daughter was a "thinker, a reflector, a reader, a writer, a dancer, a laugher. She loved her children unconditionally and knew heartbreakingly that when she was ill she couldn't look after them."

The inquest, which is expected to last three days, continues.