Mental disease is too often reduced in film to self-destructive eccentricity, sensationalist melodrama, or vilifying thrills. But as endorsed by the National Alliance on Mental Illness, writer-director Joseph Greco's convincing feature debut tries something more daring by depicting an entirely average Florida family's struggles with schizophrenia. The patient in question is Mary Marino (Marcia Gay Harden), a hobby painter already showing signs of instability by the time we're introduced to the whole clan: Her hubby John (a riveting Joe Pantoliano) is a hump-busting construction worker whose marital devotion remains steadfast no matter how many times the cops are called in, and their 10-year-old son Chris (newcomer Devon Gearhart)who vents his confusion and humiliation through school rebellionis largely the heart and entrance to the story. Through the young towhead's eyes, puppy love becomes a welcome distraction from the one-two punch of Mom's institutionalization and Dad's descent into neglect and full-blown denial. Greco's sincerity is so palpable that the frequent uplift feels deserved, but with just-passable filmmaking and the demeaning score, Canvas falls somewhere between powerful indie and made-for-TV diversion.