The first time we saw Cranston’s Casey Seymour Kim was at Perishable Theatre, where she played a parrot. That’s right, a parrot! And she was hilarious.

Kim has made a career of playing unusual roles at Perishable Theatre and the Sandra-Feinstein Gamm Theatre and as a member of Improv Jones. Known for her comedic talents, the actress has now reached deep inside herself to portray a woman haunted by mental illness.

“4:48 Psychosis” is a chilling play written by British playwright Sarah Kane, who committed suicide shortly after writing the play. Kane wrote the free-flowing play without identifying specific characters, according to Kim and Artistic Director Tony Estrella. Other groups have used a number of actors to assume different roles and voices, including a Greek chorus.

The Gamm production allows Seymour Kim to show the full range of the patient’s emotions, and she does, giving a brilliant, exhausting portrayal of a woman suffering from clinical depression.

The only other character in the intermission-less, one hour and 10-minute production is her psychiatrist, played low-key and professionally by Tom Gleadow.

Katryne Hecht’s set is a simple two-tier staging with a hospital bed, chair and table. The bricked back wall suggests confinement, but projects a wintry, snowing scene at the beginning and end, plus some of the words spoken by the patient, who also rapidly shouts out word associations.

The title stands for the one time in the early morning when the woman awakens in “a brief moment of clarity.”

While the play is very serious and intense, there are moments of black humor and even moments of hope. Primarily, the play is an in-your-face examination of mental illness. Kim, who has literally chopped her hair and made herself a bit stressed and unattractive, has captured the heart and soul of the woman she is portraying.

There are some profanity and sexual references, and this is not a play for children. But adults who have experienced mental illness or whose lives have been affected by it will certainly relate. It is intense. It will leave you exhausted. But you will leave the theatre knowing that you have had at least a peak at an illness that has affected so many people. And you will have seen one hell of a performance by a very gifted actress.

“4:48 Psychosis” is at Pawtucket’s Gamm Theatre through Feb. 7. Tickets are $24-$40; call 723-4266 for reservations.

Butler Hospital and Gateway Healthcare are co-sponsoring the production and have scheduled post-show discussions on Jan. 27 and Feb. 3.