Nicola Bulley suffered with “some significant issues with alcohol” in the past which had resurfaced over recent months, police have said.
It comes after senior officers said Ms Bulley was “vulnerable” and classed by police as a “high-risk” missing person immediately after her partner Paul Ansell reported her disappearance.
A police search involving specialist officers was launched within an hour of Mr Ansell speaking to officers, and she was deemed “high-risk” based on the information he had given them about the mother-of-two, aged 45.
“Sadly, it is clear from speaking to Paul and the family that Nicola had in the past suffered with some significant issues with alcohol which were brought on by her ongoing struggles with the menopause and that these struggles had resurfaced over recent months.
“This caused some real challenges for Paul and the family.
“As a result of those issues, a response car staffed by both police and health professionals attended a report of concern for welfare at Nicola’s home address on January 10th.
“No one has been arrested in relation to this incident, but it is being investigated.
The force has come under criticism after quickly ruling out foul play when Ms Bulley vanished after dropping off her daughters, aged six and nine, at school on January 27 in St Michael’s on Wyre, Lancashire.
She was last seen at 9.10am taking her usual route with her springer spaniel Willow, alongside the River Wyre.
Her phone, still connected to a work call for her job as a mortgage adviser, was found just over 20 minutes later on a bench overlooking the riverbank, with her dog running loose.
Nearly 40 detectives have sifted through hundreds of hours of CCTV, dashcam footage and tip-offs from the public.
Earlier on Wednesday, Detective Superintendent Rebecca Smith, the lead investigator for Lancashire Police in the case, told reporters at a packed press conference at force HQ: “As soon as she was reported missing, following the information that was provided to the police by her partner Paul, and based on a number of specific vulnerabilities that we were made aware of, Nicola was graded as high-risk.
“It’s normal in any missing person investigation that you obviously gather as much information at an early stage about the person in question, which is no different, and we did that with Paul.
“I’m not going to go into the details of those individual vulnerabilities. I’ve asked you to respect the family, who are going through unimaginable pain and distress at this moment.
“But those vulnerabilities based our decision-making in terms of grading Nicola as high-risk, and have continued to form part of my investigation throughout.”
At that time, police would not be drawn further on the exact nature of Ms Bulley’s “individual vulnerabilities”.
Senior officers were at pains to stress they did not believe anyone had attacked or abducted Ms Bulley, that they believe she had gone into the water without anyone else being involved, and to quash the “persistent myths” around the case.
Assistant Chief Constable Peter Lawson said: “There is no evidence to indicate a criminal aspect or third-party involvement in Nicola’s disappearance.”
But online amateur sleuths and social media video-makers have “distracted significantly” from official efforts to find her, police said.
Det Supt Smith added: “In 29 years’ police service I’ve never seen anything like it.
“Some of it’s been quite shocking and really hurtful to the family.”
Asked if she hoped to find Ms Bulley alive, Det Supt Smith said: “I hope with all my heart that we find Nicola Bulley alive more than anything”.
But she said all the evidence suggested that Ms Bulley went down to the river and did not return.
The search for the missing woman was extended to downstream from St Michael’s on Wyre to where it empties into Morecambe Bay and the open sea on February 3.
Police said they will soon consider the “proportionality” of continuing the huge search in coming days.