Bipolar II and the birth of a new physics

To the Editor,

The Australian and New Zealand Journal of Psychiatry has explored bipolar spectrum disorder and its coalescence into bipolar II (Kuiper et al., 2012). Some have considered the evidence sufficient for the diagnosis to have been delivered; others note difficulties. History has important lessons to teach in this regard.

Ptolemy, the Greek astronomer, modelled the Earth at the centre of the universe. This would be befitting for God’s view of man, but there were problems. Although the stars moved along fixed circular orbits, the planets did not. They wandered among the stars, planet meaning wanderer in Greek. In addition, their speed varied, their orbits wobbled and they occasionally appeared to reverse their planetary direction. Ptolemy’s solution to this was to develop a system of epicycles. However, that too could not explain all of the data. Successive modifications led to an increasingly complex system that persisted for 1300 years.

The Polish astronomer Copernicus put forward a radical view. He proposed that the Earth was but another planet orbiting around the Sun. Martin Luther condemned his ideas, as did the Vatican, and Copernicus delayed publication until 1543. His treatise remained forgotten for nearly 80 years until Galileo, an Italian scientist, who, by using the newly discovered telescope, found evidence confirming the Copernican model. He had noted the way that there appeared to be shadows on Venus which would happen only if Venus were orbiting the Sun. At the same time, Kepler, described as a tormented German mystic, was able to incorporate further unexplained phenomena. By detailing elliptical, rather than circular, movements he contended that the orbital movements of the planets could be accounted for by ellipses rather than circles. The final part of the puzzle came from the English physicist and mathematician, Sir Isaac Newton. He determined that the gravitational force that causes an apple to fall to earth was the same force that holds the moon in its orbit around the Earth. It had taken 150 years, with contributions from different countries and different disciplines to solve the puzzle of planetary motions (Cohen,1960).

It may transpire that the concept of bipolar II disorder as it is currently described is correct. However, there are difficulties (Little and Richardson, 2010). It was the ability of the unexpected, and for the discoverer to remain outside existing theories and observations, which enabled the critical paradigm shifts required to advance knowledge. Inconsistencies are important as they stimulate further exploration and the possibility of a clearer and livelier impression of truth.

Diagnosis may be more usefully considered as a hunch held lightly (Malhi, 2013) rather than a decision to be defended (Sachdev, 2013). Symptomatic responsivity is of interest, not of diagnostic confirmation. We should move cautiously before adopting a diagnosis uncritically. To do otherwise diminishes both psychiatry and science.