The Wizarding world did in no way attempt to deny that as far as mental health went, it was centuries behind the muggle world. Mind you with things like dementors and boggarts - a simple "chemical imbalance" wasn't out of the realm of possibility….it just fell to the wayside when things like dark lords and Unspeakables needed to be attended to. It was generally accepted that any witches and wizards that were….down….were because of a reason. After that, much thought wasn't taken.
There was, however, one agreed exception to this thinking through out the wizarding world, the loss of a mate - or indeed the inability to be with said mate- created a hole in a magical beings chest that could be either eased (but not cured) with the third mate…..or it would spread until the Wizard or witch died of a broken heart (cardiomyopathy to muggles). It was not uncommon for suicide to occur.
The muggles called it depression. Well to be honest they call it a multitude of things. Different words and phrases which essentially meant the same thing. Unfortunately it was all too common an occurrence with the current generation. Muggles thought it was due to increased softness of snowflakes or the introduction of social media…..the majority of wizards had no idea what that was.
As with any war, there were loss of partners, leading to nights of seeking solace in strangers' arms which led to many illegitimate children. Some were born to muggles who had no idea they had slept with a magical being - and others were left in muggle orphanages in attempt for a witch to pretend that her night of indiscretion never occured. This, coupled with the predictable baby boom once the war ended; meant that a stiff incline in the number of muggle or muggle born children who were thought to be "depressed" actually being mates with magical beings that could only watch on as their beloved suffered.
Which is how Severus and Harry found themselves every second Sunday, with Whiskey in hand - gazing into the enchanted globe on the desk in front of them, watching their third as she attempted to fix a magical problem with muggle tools.
Sometimes it was OK. It seemed their little mate was a musician of sorts. She liked to sing, and would do so randomly through out the day, usually humming as she went about her chores. Neither of them made a habit of learning muggle music - but Severus especially had become fond of one of the songs she seemed to repeatedly favour. It gave Harry a bitter-sweet smile when he heard his love humming that song while cooking or working. "So far away…doesn't anybody stay in one place anymore…" Whenever she would start to sing the first words, he would watch as the smile grew on the potion master's face, as he hummed along. The bespectacled man laid his head back and closed his eyes as he heard the mix of timber baritone and alto collide in a song that would forever mean love to him.
Other days it was bad. She had no name other than what the muggles gave to her, and there were many - depression, bipolar, borderline; take this pill that pill, this therapy etc. Each time she accepted the help and did as was bid of her. But all three of them knew none of the answers would help. The men knew that without them she would never be "happy" and she knew that no matter how many drugs she took or people she spoke to; she would never be "cured".
Some days it was really really bad. On those days; Severus would never allow Harry to watch. Claiming it would be to difficult for the younger man. It hurt the Gryffindor, but he accepted his mate's decision and would retire to the bedroom, where he would wait to soothe the pain the older man would feel. Together attempting to ease the suffering of an ache they both knew would never leave entirely. On those days Severus would lock the door behind Harry, would accio the whole bottle of Whiskey and would allow silent tears to fall. On these days she didn't leave the bed or shower - simply sitting there; sometimes she cried, but on the worst days she just sat with no expression on her face. As though she was waiting for her time to be up and death to finally embrace her. These were far worse than the days in which she harmed herself; these were the days were Severus sometimes wished death would come - to save them all.
The muggles made tell of a magical land called "Heaven" perhaps, when all the suffering was over they could finally be together. Or at least, she and Harry could. Harry had explained that it was were good people went after death - that counted Severus out. But maybe, maybe when death did come for them all; Harry would finally be able to help soothe some of their sweet mate's aches. Even if it meant that Severus would have to say goodbye to him.