Actress and writer Carrie Fisher, best known for her role as Princess Leia in the original Star Wars films and her decades of mental health advocacy, died last week after suffering cardiac arrest on a flight. She was 60 years old. But a recent report in Scientific American asks: Could the bipolar disorder the star openly lived with have played a role in her death?

Also called manic depression, bipolar disorder (BPD) is a chronic mental illness characterized by extreme shifts in mood, energy, activity levels and the ability to carry out day-to-day tasks. Throughout her career, Fisher spoke out about her experiences with BPD, with which she was diagnosed in her early 20s, as well as with drug and alcohol. The actress’s honesty about her struggle with BPD helped counter the stigma associated with psychiatric disorders.

Since her death, some have conjectured that Fisher’s past struggles with substance abuse might have contributed to her death. But mental health experts have also speculated that bipolar disorder, which recent findings link to cardiovascular risks and mortality, might have been a factor as well.

In 2009, a population-wide study published in the journal Psychosomatic Medicine theorized that people with bipolar disorder are almost twice as likely to develop or die from heart disease than would otherwise be expected. Related findings published in 2015 in Circulation, another medical journal, found that the onset of cardiovascular disease also occurs much earlier in people with the psychiatric disorder—up to 17 years sooner than in the general population.

Additionally, many of the antipsychotic medications used to treat bipolar disorder can trigger adverse effects that include weight gain, elevated triglyceride levels, an increased risk of diabetes and even sudden cardiac death due to an abnormal heart rhythm, a.k.a. arrhythmia. The physical and mental stress of swinging between bipolar disorder’s highs and lows, which can boost inflammation, could also have put excess strain on Fisher’s heart.

“There is also evidence of problems with the function and structure of blood vessels among people with bipolar disorder, and this occurs in the brain as well as the body,” said Benjamin Goldstein, MD, PhD, a child and adolescent psychiatrist at the University of Toronto and author of the 2015 Circulation study.

Although much more research must be done to solidify this link, mental health experts said that certain facets of Fisher’s life fit the bill for at least several of the risk factors previously mentioned.

But doctors also stress that there is no definitive way to confirm whether the entertainer’s bipolar disorder factored into her death. With further research of psychiatric illnesses, they said, we may soon be closer to an answer. 

Click here to learn more about bipolar disorder, its signs and its available treatments.