Dave is a frank, engaging speaker whose words tumble out swiftly, and he is not shy about the condition that he believes took hold nearly a half-century ago, when he was a teenager in Toronto’s east end. “I’m manic-depressive,” he says. “I’m just not comfortable with calling it ‘bipolar disorder,’” he says, swiping his palm through the air as if brushing the term away. “It’s a softening of the harsh reality of what is a debilitating disorder that has you oscillating between hypomania or mania and between mild, moderate and severe clinical depression. Bipolar makes it sound gentle,” he says, his blue eyes wide. “There’s absolutely nothing gentle about it.”

Everybody around Lauren Thompson understood that she was different when she was just a toddler, and would erupt into tantrums at the slightest provocation. First she’d bang her head against the wall, then weep inconsolably for several minutes, and end the cycle with uncontrollable giggling. Her mother Gen was at a loss. “She’d be crying, crying, crying, and then stop abruptly and burst out laughing.” Gen never understood what triggered her little daughter, and never knew how to help stop it once it started.

Cristina is laser-like when she identifies herself: She is 47, and the mother of three children. She has a demanding job as an insurance broker and has been married for almost two decades. The nuances, though, are a bit more complicated. And during a long discussion at her home in North Lawrence Park that is so surrounded by rock and trees, visitors might be forgiven for thinking they were in a treehouse. There is the gleaming all-white kitchen and a modern light fixture that glitters above a harvest table, all overlooking an impeccably devised patio that serves as an outdoor living room.