Every month, I get a schedule of upcoming press screenings of movies. I look up their two-sentence plot summaries on IMDb, choose the ones I want to see, add their dates and venues to my iPhone calendar, and then forget about them completely until that day. I never watch trailers and try not to read anything about these films. Even that morning, if you asked me what tonight’s movie will be about, I couldn’t tell you. This is usually a good thing, because I walk into the theater with a blank slate, ready to be entertained by whatever is projected onto the screen.

But I wish I’d paid more advance attention to the plot of “What They Had,” a movie about a woman in her seventies suffering from dementia.

The problem is that the subject hits too close to home for me. My 94-year-old mother has been suffering from dementia for over a year, and she’s not doing well. My brother and I have to handle all of her affairs. He visits her regularly while I — a thousand miles away — call every week and fly east to visit every couple of months, but every encounter leaves me sad and a little distraught. On top of that, my 85-year-old mother-in-law has the disease, too, although it’s not as pronounced. Still, it’s very hard to deal with — for both women, their children, their grandchildren, and the healthcare professionals trying to help them. So, sitting in the theater watching “What They Had” ripped me apart emotionally.

Ruth, the woman in question, is played by Blythe Danner, who displays many of the attributes of a person with that condition. For instance, she keeps asking “Where’s my purse?” It’s a query female dementia patients make all the time, as if their very identity were in that bag.

Robert Forster — in his best role since Quentin Tarantino’s “Jackie Brown” — gives a bravura performance as Burt, Ruth’s husband, who is devoted to her care. Unfortunately, he can’t keep Ruth from wandering out of the house and down the street in the snow in the middle of the night while he’s asleep, as she does in the opening scene. That’s why their son Nick (Michael Shannon, another actor incapable of a bad performance) wants to put Ruth into a memory-care center that can keep her comfortable and safe. Nick is the one who has to come running every time there’s a problem Burt can’t handle alone, and the burden of that plus running his own bar is getting to be too much for him. So Nick calls his sister, Bridget (Hilary Swank) to insist she fly in from California and help him convince Burt that the time has come to sell the Chicago condo he and Ruth live in, put her in the assisted-living facility, and get his own apartment nearby. Burt won’t hear of it, and hence the conflict at the center of the story.

Elizabeth Chomko directed “What They Had” from her own script, which must have been somewhat autobiographical, and was lucky to have cast four stars who can rise above the somewhat predictable material. Playing an adult riddled with dementia can be a path to awards recognition: Julianne Moore won an Oscar for “Still Alice” (2014) and Frank Langella won a Tony for “The Father” (2016). I saw both of them and admired their performances — but that was before we had to deal with the issue in our own family. I don’t think Danner will be nominated for this, but Forster might. He’s that good.

If you’re in the midst of a family dementia crisis, you might not want to spend a couple of hours in a theater watching the effects of this horrible disease. But if you aren’t — or if you’re stronger than I am — you may want to see “What They Had.” The performances of Swank, Shannon, Danner, and especially Forster make it worthwhile.

I give it a 7 out of 10.