The smartphone application called BiAffect says it can tell how a person's mood is by predicting the person's mood through analysing their keystrokes, their speed of typing, how hard the keys are pressed and how often they use backspace or spellcheck.
The app was developed by Alex Leow and Peter Nelson, psychiatrists from the University of Illinois at Chicago.
Nelson said: "I began working on this idea many years ago as a way to help my son, and to see it come to fruition with this kind of recognition, and to know that the app will be out there to help people get a better understanding of this disorder is thrilling."
Whilst Leow added: "The vision for BiAffect is for it to serve as a kind of 'fitness tracker' for the brain. The Mood Challenge helped us to realize this vision, and the finished app will be a first-of-its kind tool for researchers to study mood disorders and even cognitive disorders such as Parkinson's and Alzheimer's disease."
When someone is experiencing a manic episode, those with bipolar disorder tend to talk very fast and do similar when they type.
Explaining how the app works, Leow shared: "During a manic episode, people with bipolar disorder exhibit some common behaviours, such as talking really, really fast, with diminished self-control and flight of ideas. It is thus natural that they also exhibit similar abnormalities in nonverbal communications that are typed on their phones.
"People in the midst of a manic episode commonly have reduced impulse control, so it is not surprising that our pilot data supported that they tend to blow through the spellcheck alerts."