It has been frequently noted that creative people seem to have a disproportionate rate of mental illness. Studies have since borne this out, particularly among writers. Mood disorders may be the most common form of mental disorder among writers, who have an elevated rate of both depression and bipolar disorder. Consequently, there is a disproportionately higher rate of suicide in these artists. For example, the novelists Ernest Hemingway and Virginia Woolf both committed suicide, as did the poets Anne Sexton and Sylvia Plath. It is not clear why creativity and mood disorders are linked to each other, although researchers have speculated that the intense emotionality of a mood disorder heightens the sensitivity of creative people. Additionally, people with bipolar disorder can be extremely productive and creative when in a hypomanic state. Hypomania is a milder form of mania, when the elevation of mood and the increase in energy and self-confidence have not yet led to functional impairment.