Writer-director P.J. Hogan may have based "Mental" on an actual incident from his childhood, but the crazy quilt of a movie that resulted feels anything but real.
This strained, shrill effort, set in small-town Australia, revolves around the über-quirky Moochmore clan: "Sound of Music"-obsessed mother Shirley (Rebecca Gibney), absentee dad — and local mayor — Barry (Anthony LaPaglia) and their five off-kilter daughters. When Shirley has a colorful nervous breakdown, Barry sticks her in a mental hospital, then randomly hires screwy, knife-wielding hitchhiker Shaz (Hogan's "Muriel's Wedding" star Toni Collette) to tend his children.
If Hogan simply followed the story's initial track — bad nanny Shaz teaches her unstable young charges confidence and strength as she redefines crazy and reunites a family — the movie might have had a shot.
Instead, chaos reigns, as things veer off into a whirl of wacko directions involving Trevor (Liev Schreiber), the unhinged owner of the shark show where eldest Moochmore daughter Coral (Lily Sullivan) works; Trevor's muddled history with Shaz; Shirley's doll-fixated sister (Caroline Goodall); the Moochmores' clean-freak neighbor (Kerry Fox) and her budding lesbian daughter; an annoying lifeguard-musician (Sam Clark) and lots of Rodgers and Hammerstein.