Missing woman Nicola Bulley suffered with "some significant issues with alcohol" in the past, which had resurfaced over recent months, police in England 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.
She was deemed "high-risk" based on the information he had given them about the mother-of-two, aged 45.
This evening, a statement on the Lancashire Police website said: "We have described how Nicola had some vulnerabilities at the time she went missing and we just wanted to expand on that a little.
"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.
"It is an unusual step for us to take to go into this level of detail about someone's private life, but we felt it was important to clarify what we meant when we talked about vulnerabilities to avoid any further speculation or misinterpretation."
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In an earlier press conference, police said Ms Bulley was graded as high-risk based on a number of "specific vulnerabilities".
However, they did not comment further on the exact nature of Ms Bulley's "individual vulnerabilities", which led to speculation online.
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.
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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.
Since she vanished, huge public and media interest has resulted in what police described as "false information, accusations and rumours" and an "unprecedented" search of both the River Wyre, downstream to Morecambe Bay and miles of neighbouring farmland.
Nearly 40 detectives have sifted through hundreds of hours of CCTV, dashcam footage and tip-offs from the public.
Assistant Chief Constable Peter Lawson said: "There is no evidence to indicate a criminal aspect or third-party involvement in Nicola's disappearance."
Police said that while keeping an "open mind", their "main working hypothesis" remains that Ms Bulley went into the river during a "ten-minute window" between 9.10am and 9.20am that day.
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 3 February.
Police said they will soon consider the "proportionality" of continuing the huge search in coming days.
