at a faster rate. Consistent with this hypothesis, ambidexterity is also more common in people with schizotypal personality disorder as well as people with schizophrenia. Three studies by Mark Batey and Adrian Furnham have demonstrated the relationships between schizotypal and hypomanic personality and several different measures of creativity. Specifically, Divergent Thinking Fluency, the Biographical Inventory of Creative Behaviors, as well as Self-rated Creativity. Particularly strong links have been identified between creativity and mood disorders, particularly manic-depressive disorder (a.k.a. bipolar disorder) and depressive disorder (a.k.a. unipolar disorder). In Touched with Fire: Manic-Depressive Illness and the Artistic Temperament, Kay Redfield Jamison summarizes studies of mood-disorder rates in writers, poets and artists. She also explores research that identifies mood disorders in such famous writers and artists as Ernest Hemingway (who shot himself after electroconvulsive treatment), Virginia Woolf (who drowned herself when she felt a depressive episode coming on), composer Robert Schumann (who died in a mental institution), and even the famed visual artist Michelangelo. A study by Simon Kyaga and others looked at 300,000 people with schizophrenia, bipolar disorder or unipolar depression, and their relatives, found overrepresentation in creative professions for those with bipolar disorder as well as for undiagnosed siblings of those with schizophrenia or bipolar disorder. There was no overall overrepresentation, but overrepresentation for artistic occupations, among those diagnosed with schizophrenia. There was no association for those with unipolar depression or their relatives. A study involving more than one million people, conducted by Swedish researchers at the Karolinska Institute, reported a number of correlations between creative occupations and mental illnesses. Writers had a higher risk of anxiety and bipolar disorders, schizophrenia, unipolar depression, and substance abuse, and were almost twice as likely as the general population to kill themselves. Dancers and photographers were also more likely to have bipolar disorder. However, as a broader group, those in the creative professions (defined as "scientific and artistic occupations") were no more likely to experience psychiatric disorders than other people, although they were more likely to have a close relative with a disorder, including anorexia and, to some extent, autism, the Journal of Psychiatric Research reports. Research in this area is usually constrained to cross-section data-sets. One of the few exceptions is an economic study of the well-being and creative output of three famous music composers over their entire lifetime. The emotional indicators are obtained from letters written by Wolfgang Amadeus Mozart, Ludwig van