The Scottish mother-of-one is now recovering at her North-West London home after being discharged from hospital.
According to The Sun, Porter - who was diagnosed as suffering from alopecia after losing her hair - was found in her bathroom on Wednesday night in a state of distress with cuts to her arms and chest.
"Police were called to an address in Belsize Park, London at approximately 21.00 hours on Wednesday following concerns for the welfare of a resident," a Met Police spokesperson said. "A woman was detained under the Mental Health Act and taken to a medical facility."
Upon her return to the property with boyfriend Jonny Davies, the 40-year-old told the paper: "I'm fine, thank you very much."
She previously described a 2005 overdose as a "cry for help", adding that it was the "biggest mistake" of her life.
> Porter 'taken more seriously with alopecia'