10/03/2012 06:10 pm ET Updated Oct 04, 2012

Bipolar Disorder: Lark Voorhies, 'Saved By The Bell' Actress, Diagnosed With Condition, Her Mom Says

"Saved By The Bell" actress Lark Voorhies has been diagnosed with bipolar disorder, her mom told People magazine.

"There are things that have traumatized her," Voorhies's mom, Tricia, told the publication (Tricia and Lark live in the same home together). "I care deeply about my daughter and I want her to resume her life."

However, the 38-year-old, who played Lisa Turtle on the TV show, told the publication that she isn't sick.

Bipolar disorder is characterized by mood swings from mania to depression, though the intensity of these mood swings can depend on the person and severity of the condition, according to the Mayo Clinic.

The condition is considered a mood disorder; mood disorders occur when brain chemicals are imbalanced, and can be contributed to by major negative life events, Ohio State University reported.

There are three main subtypes of bipolar disorder -- the first, bipolar I disorder, is the most severe; the second, bipolar II, has less severe symptoms, but the feelings of depression may last longer. Cyclothymic disorder is the least severe of the three types, where the episodes of depression and mania are not as intense, the Mayo Clinic reported.

When a person with bipolar disorder is experiencing mania, it may manifest with symptoms of extreme agitation, jumpiness, extreme happiness, distractedness, restlessness, wanting to engage in risky behaviors, not getting a lot of sleep and fast talking, according to the National Institutes of Health.

Meanwhile, symptoms of depression may manifest with loss of interest in activities, irritability, problems eating and sleeping, concentration issues and feeling worried and tired, the NIH reported.

The exact cause of bipolar disorder is not known, but researchers suspect genetics play a part, according to the National Institutes of Health.

Medications are usually used to treat bipolar disorder, though psychotherapy and some other kinds of treatments -- like electroconvulsive therapy -- may also be employed, according to the Mayo Clinic. Hospitalization is sometimes required.