Gordon Parker’s bipolar disorder research

General comments

Amongst Gordon Parker’s broad range of clinical research interests, one of the enduring areas of focus has been bipolar disorder. In that area alone, he has published (as of September 2025) 213 articles, with an increased frequency of papers on that topic in recent decades.

Prior to drilling down on Gordon’s bipolar disorder publications, some general comments on his approach to research are apt.

First, Gordon has always been the consummate lateral thinker. He has been reluctant to accept contemporary dogma or ideology, be that focused on accepted “wisdom” in the field, or on classificatory systems, with a particular target in recent years being the approach of various iterations of DSM. Related to that, he has shown himself to be a contrarian by nature, being actively, enthusiastically, and passionately engaged in controversies and debates. He thrives on intellectual combat.

Second, Gordon has always been a busy and active clinician, in addition to his prodigious academic (and in the past also administrative) energy and productivity. He has not compartmentalised these aspects of his career, rather applying his clinical insights to his research, bringing to his academic quests the thoughtful and creative perspective of a clinician researcher.

Third, he writes clearly, accessibly and persuasively. Prior to his academic career in psychiatry, he had entertained a career as a novelist or playwright, with the skills developed in those literary pursuits facilitating his capacity to communicate lucidly and engagingly in the academic arena. One aspect of that is his mastery of the clever title or apt quotation.

These three attributes will be further elaborated upon in the following expositions of some of his major areas of focus in his bipolar disorder research.

Gordon’s bipolar disorder themes: a selection

Gordon has undertaken an impressive breadth of bipolar disorder research over his career of over five decades. As it is not possible to do justice to all his publications, I have decided to focus on some of his main research themes, as well as arbitrarily choosing some particular areas of interest.

First, I will examine some of his early research, published in the 1970s, in areas such as early childhood parental bonding, and differing rates of the diagnosis of bipolar disorder in different countries.

Second, Gordon has had an enduring interest in the phenomenology of psychiatric conditions, particularly in unipolar depression and bipolar disorder. In this section I will focus on his studies on the phenomenology of bipolar depression, including rates of melancholia in that condition. I will also discuss his clinical observations of “suprasensory experiences” in mania.

Third, I will focus on his interest in diagnostic criteria. While much of his early work on diagnostic criteria focused on the definition of melancholia in unipolar depression, here I will focus on his papers on diagnostic criteria for bipolar II disorder, with a particular emphasis on criteria for elevated episodes.

Fourth, related to diagnostic criteria, is an enduring interest in diagnostic boundaries between disorders, with a prominent series of studies on the boundaries between bipolar disorder and borderline personality disorder – a long-standing conundrum for clinicians as well as researchers.

Fifth, as a practising clinician, Gordon has had an ongoing interest in treatments for bipolar disorder, particular those for bipolar II disorder. The particular therapy upon which he has focused is lamotrigine, and its specificity or otherwise for bipolar II.

Sixth and last, some of Gordon’s most interesting publications are what I will term “fun stuff.” Through his career Gordon has submitted “fun stuff” papers for the Christmas issue of the Medical Journal of Australia, which publishes entertaining articles (but nonetheless usually humorously addressing substantive issues). One of his articles of this genre in bipolar disorder addressed the question of whether the mathematician John Nash had bipolar disorder rather than schizophrenia.

Early bipolar disorder research

I will focus on two of Gordon’s bipolar disorder papers from his early years as a young academic at University of New South Wales. The disparate nature of these highlights the breadth of his interests and his curious intellect.

The first ¹ arose from the contemporaneous findings of major differences in the rates of diagnosis of conditions such as schizophrenia and bipolar disorder between the US and UK, reflecting distinct diagnostic practices between those two countries. Examining rates of diagnoses of the various “functional psychoses” in hospitalised patients in New South Wales compared to those in England and Wales, Gordon found no differences in the rates of diagnosis of mania, indicating similar diagnostic practices for bipolar disorder in Australia and the UK. There were, however, slightly greater rates of the diagnosis of schizophrenia in NSW, and slightly lower rates of psychotic depression, suggesting some subtle differences in diagnostic practice for those disorders, but nothing as dramatic as had been found between the US and UK.

The second paper I have chosen from Gordon’s early years was an investigation of the Parental Bonding Instrument (PBI) in patients with depression due to bipolar disorder (manic-depressive illness) compared to controls and those with “neurotic depression.” ² The PBI ³ had been developed as a measure of the perception of adults of their childhood experiences of their parents parenting style, with a focus on care and overprotection. In this paper, ² Gordon found that bipolar depressed patients scored like controls on the PBI, whereas those with “neurotic depression” reported less parental care and greater maternal overprotection, supporting the contention that bipolar disorder was a biological condition unrelated to childhood experiences, whereas neurotic depression was associated with adverse experiences in childhood, particularly related to the parenting style.

Phenomenology

Gordon has always had a strong interest in the phenomenology of depression, with a particular interest in characterising melancholia in unipolar depression as a potential means of distinguishing between melancholic/endogenous depression from non-melancholic/reactive depression. He subscribed strongly to the “binary” view of classifying depression (i.e. melancholia v. non-melancholia) as opposed to the current predominant dimensional conceptualisation, with a spectrum of depressive presentations related to severity rather than categorical differences. His team developed the CORE system for rating psychomotor disturbance as a means of objectively rating features of melancholia. ⁴ In a seminal study, ⁵ comparing 83 bipolar and 904 unipolar depressed patients on three melancholic sub-typing systems (DSM, Clinical, and CORE system), he found that bipolar depression appeared to be more likely to be “melancholic” in type than unipolar depression, particularly being distinguished by psychomotor disturbance and pathological guilt.

Another study exemplifying Gordon’s interest in phenomenology was a clinical tour de force on “suprasensory” experiences during hypomania, derived from his acute clinical observations. ⁶ A graphic quote from this paper: “The bipolar II patients I have talked to have provided a number of examples of such suprasensory changes experienced during ‘highs’, which generally attenuate or disappear during depressive and euthymic periods. Smells are commonly magnified, especially ‘smells of nature’, such as grass, rain, dust, flowers, and pollen, but also toiletries, cleaning products, body odors, food, and particularly coffee. Not only is the sense of smell amplified, but it also can persist, with one woman describing the smell of gasoline continuing for 6 hours after exposure.”

Diagnostic criteria: bipolar II disorder

One of Gordon’s long-standing and dominant interests in bipolar disorder has been that of bipolar II disorder, a focus for which he has been recognised as one of the leading figures internationally. Overviews of his work in this area can be found in the peer-review literature ⁷ and the multi-edition Cambridge University Press book “Bipolar II disorder: Modelling, Measuring and Managing.”

One of Gordon’s main areas of interest in bipolar II disorder has been on the means of distinguishing this from bipolar I disorder. He has largely focused on the duration of hypomania. A pivotal paper ⁸ examined the validity of the DSM-IV and DSM–5 definition of a minimum duration of 4 days as the threshold criterion for hypomania. His group contrasted findings between those meeting the DSM minimum duration of 4 days with those experiencing episodes lasting less than 4 days. They found few differences between these groups, arguing that “the DSM duration of 4 or more days for a diagnosis of a hypomanic episode is unnecessary to the clinical definition of a BP II disorder.”

Gordon has been involved in passionate debates about both the validity of bipolar II disorder as a legitimate subgrouping of bipolar disorder and his own diagnostic conceptualisation of this. ⁹ His quote at the beginning of that article reveals his passion about this contentious issue: “The work of science has nothing to do with consensus. Consensus is the business of politics. Science, on the other hand, requires only one investigator who happens to be right (with)…results that are verifiable by reference to the real world – Michael Crighton.”

Treatment: lamotrigine

Gordon’s ongoing interest in the management of bipolar disorder (particularly bipolar II disorder) reflects his clinical academic’s focus on optimising outcomes for patients with this highly disabling condition. One of his main interests has been the place of lamotrigine in the management of bipolar II disorder. I have selected two of his papers on this topic.^10,11

The first paper ¹⁰ addressed the previously unstudied issue of comparative effectiveness of maintenance lithium and lamotrigine in bipolar II disorder. Forty-four subjects with a newly diagnosed bipolar II disorder were randomly assigned to either lithium or lamotrigine treatment in a 20-week single-blinded study. Analyses of study completer data for 28 participants suggested comparable efficacy of both medications, but conclusions were limited by the small sample size.

In the second paper, ¹¹ 246 individuals with bipolar disorder (84 bipolar I and 162 bipolar II) completed an online survey containing questions including effectiveness/side effect profiles of bipolar disorder medications that they have taken. The study found that lithium and lamotrigine were the most commonly prescribed medications, with lithium and lamotrigine appeared marginally more effective for BP-I and BP-II, respectively, with only the latter difference being statistically significant. Lamotrigine had the more favourable side effect profile.

Fun stuff: did John Nash (“A Beautiful Mind”) have bipolar disorder?

One of Gordon’s articles of this genre in bipolar disorder ¹⁴ addressed the question of whether the mathematician John Nash – who won the Nobel Prize for Economics in 1994 for his work on game theory (and popularly of fame from the movie “A Beautiful Mind”) – had bipolar disorder rather than schizophrenia. While arguing persuasively for Nash in fact having bipolar disorder, his article concludes: “The definitive nature of John Nash’s condition is unlikely to be easily established, but it certainly deserves to be questioned with respect.”