A study by psychologist J. Philippe Rushton found creativity to correlate with intelligence, aggressiveness and interpersonal hostility.
Another study found creativity to be greater in individuals who present with minor schizoid symptoms (schizotypal) than in either normal or schizophrenic individuals.
While divergent thinking was associated with bilateral activation of the prefrontal cortex, schizotypal individuals were found to have much greater activation of their right prefrontal cortex.
During times of stress even those with integrated brain hemispheres, tend to favor their right hemisphere and can become swept up in their richly emotionally Contexualized memories. Left hemispheric dominant individuals, under stress, are drawn into their fact based semantic memory and can seem very legalistic and reasonable, though they lack the potency or passion that their episodic memories would provide them.
An integrated neocortex, and ultimately integration of the entire brain, allows for divergent imaginative thinking and true healthy creativity. A polarized cerebrum, where the left or right hemispheres function in isolation particularly in times of severe stress, presents as one form or another as what we would label as acute mental dis-ease.
This study hypothesizes that such individuals are better at accessing both hemispheres, allowing them to make novel associations at a faster rate. Their brain speed is greatly enhanced upon hempisperical integration and creativity provides those with integrated brains a positive feedback when creativity is released.
In agreement with this hypothesis, ambidexterity (both hands, both hemispheres) is also associated with schizotypal and schizophrenic individuals.
Three recent studies by Mark Batey and Adrian Furnham have demonstrated the relationships between schizotypal and hypomanic personality and several different measures of creativity.
Hypomania is a result of a usurped superego, and a shadow/ego integrating psyche, without the concomitant integration of the two brain hemispheres and an adequate intrinsic motivation required from a strengthened identity. Too much energy is available, without enough free flow or speed of brain processing, due to disparate right and left hemispherical circuitry inconsistencies.
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).
These are often misidentifications, or misdiagnoses of the creative process by ignorant mental health professionals, as these are manifestations of asymmetrical hemispherical inconsistencies with concomitant excessive psychic energy release.
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.
Another 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.
According to psychologist Robert Epstein, PhD, creativity can be obstructed through stress. Like any other human expression, creativity must necessarily become obstructed when we allow external concerns to usurp our focus.