A man has described the "mental pain" his depressed daughter suffered before killing herself by running in front of a lorry on the M4.
Cheryl Palmer "always gave 120% of herself", her father said
An inquest heard how Cheryl Palmer, 37, from Sandfields in Swansea, carefully planned her own death by pretending her car had broken down.
Victor Palmer told the Swansea inquest his daughter had "great energy" before being tortured by depression.
Coroner Philip Rogers recorded a suicide verdict on the "tragic case".
Mr Palmer said his daughter, a talented speech therapist who helped autistic children, was clever and articulate.
"She really enjoyed life and lived life with great energy," he said.
"She always gave 120% of herself and was dedicated to her job, and was always conscientious.
"Unfortunately, she had an episode of depression and was given tablets for that.
"She was on those tablets for about five years or so and was keen to come off."
He said she felt good about her life in Swansea, had a fiancÚ, and came off her medication.
But he said she went into a deep depression without the tablets.
There were long delays on the motorway following the incident
He added: "She went down to the depths of mental pain. The terror and anxiety she suffered is not far short of torture."
The inquest heard how Miss Palmer ran out into the path of a lorry travelling at more than 50mph last May.
She had stopped her Volkswagen car on the western carriage of the M4 near junction 47, at Swansea.
When a traffic officer came to her aid she told him her car regularly broke down, but that the AA was on its way.
However, checks later revealed the car had no mechanical fault and the AA had not been called.
The officer got Miss Palmer to move her car to a less dangerous spot and left, but within minutes she ran in front of the lorry.
In a statement, lorry driver Michael Schorer described how he had no time to stop.
'Like a doll'
"Then this person started walking very fast or running into my lane directly in front of me," he said.
He said that when he hit the woman, "I could see her fall like a doll onto the other lane".
Witness Richard Edwards saw the accident as he approached on the eastern carriageway of the M4.
"She was running, the lorry was on the inside lane. I don't think there was anything the lorry could have done to avoid the collision," he said.
Miss Palmer died from multiple injuries the next day. She had tested negative for alcohol and drugs.
Swansea Coroner Philip Rogers said: "The obvious verdict is that Cheryl Palmer took her own life. I have no doubt about that.
"Cheryl deliberately stepped or ran out in front of the lorry.
"This is clearly a very tragic case for the family and her fiancÚ."