Today's fish and chip paper, tomorrow's career

LW: How did you come be a neuropsychologist – was it something you set out to become or did it evolve?

JB: I think it just actually happened, a sort of interesting history of coincidences. In school I turned out to be quite good at Latin and Greek, so I was under pressure to study these subjects at university. However, I become interested in science because the local chip shop used to wrap up chips in old copies of The Lancet! As a very young kid, I used to read these greasy back copies and I got excited by medicine.

Unfortunately classicists didn't do much in the way of lab work in school so I set up a lab in the greenhouse where I had great fun with all sorts of chemicals like nitric acid, sulphur, potassium chloride, things you couldn't get hold of today. I then got a scholarship to Oxford… I started by taking classics but managed to change to a new course, 'PPP'– physiology, psychology and philosophy. I didn't enjoy the philosophy one bit, but I did enjoy the psychology and the physiology.

When I graduated in 1962, I got a job with ICI in London. This brought me into contact with a new high-powered computer – the IBM 1401. As I was developing my computing skills my old tutor at Oxford, Harry Kay, was setting up a new department at Sheffield and suggested that I might want to do a PhD. Quite by chance, I ended up sharing a room with somebody who took Scientific American and there I discovered a paper by Eckhard Hess, on pupillary responses to emotional stimuli.

I thought we could improve on that and as it happened we had all of the equipment close to hand – a dark room, a stable floor and a cine camera. I had to find a way of upgrading the 800 ASA to 16 000 ASA by a very prolonged developing technique, and we eventually published an article on pupillometry and information processing in Nature. I got my PhD in two years and that really got me into the business of neuropsychology.

LW: Talking about neuropsychology, you published a book in 2000, Developmental Disorders of the Frontostriatal System, in which you made two interesting propositions. First, you suggested that six psychiatric disorders, schizophrenia, ADHD, autism, depression, OCD and Tourette's syndrome, are all part and parcel of a continuum; and second, they may exhibit adaptive features in human evolution.

JB: This was basically a multilevel argument that all six have a number of things in common. They all involve the frontostriatal system (broadly the prefrontal cortex and parts of the basal ganglia), they are all developmental disorders as opposed to degenerative ones, and they all have adaptive aspects (either for the sufferer or for their relatives), otherwise they would have been removed from the population.

LW: If they are all part of a continuum, then what do you think determines which of these pathways people end up taking with disorders like that?

JB: I think this opens interesting theoretical and experimental questions.

I think it is determined by the amount and the exact locus of dysfunction within the greater frontal-striatal pathways. This is basically shorthand for the pathways between the frontal lobes and the basal ganglia. There are probably five of these pathways, two of which are involved in limb and eye movement, but the other three are involved in cognitive and social functioning. One of these, the dorsolateral prefrontal route is involved in executive functioning – for example, maintaining fluent cognitive processes. Another, the orbitofrontal route, amongst other functions plays a role in inhibiting behaviour, and the final one, incorporating the anterior cingulate, may involve error detection and correction, and is very important in terms of drive, motivation and emotional or limbic processes. A dysfunction here could lead to excessive or inadequate emotions, which are clearly facets of both schizophrenia and autism.

But we can see that problems in all three pathways are likely to be related to these neuropsychiatric conditions. Which of the six disorders you end up developing probably depends on how over- or under-modulated these three pathways are. In fact, if you look into all these disorders there is a great deal of overlap and comorbidity. With Tourette's you are often very close to aspects of obsessive compulsive disorder. You may experience simple motor compulsions, also perhaps with a tendency to profanity. With OCD you also may exhibit certain of the  scatological aspects of Tourette's, along with characteristically much more complex obsessions or compulsions. The two disorders also share features with bipolar disorder and schizophrenia. Also, the hypomanic aspect of bipolar disorder merges into schizophrenia, and some aspects of schizophrenia are very close to autism. In autism you have features of ADHD and vice versa.

According to DSM-IV you can't have both autism and ADHD – but we have shown quite clearly that you can! It is all a matter of definition. These disorders aren't like heart disease, where you've got something physical we actually can look at. These are actually psychiatric constructions, and psychiatric disorder has to be seen in the context of the current expectations and norms of society. That brings you back to the genetic and evolutionary aspects of it.

LW: A lot of the problems that sufferers have with these disorders are quite debilitating in today's society. Is it possible that they may have been advantageous in the past?

JB: Yes – take Joan of Arc, she may well have had ADHD and a form of psychosis. She would probably be institutionalised nowadays, but of course she was a heroine in her time. Perhaps elements of ADHD are just what you want if you're a soldier having to react instantaneously to any unexpected emergency.

But even today there may be positive features that help to keep these disorders in the population. Autistic and obsessive tendencies may be quite useful if you are a physician or a mathematician. A little obsession can get the job done. And it is very interesting if you look at the close relatives of these people. Mild forms of autism are clearly associated with successful computational careers. Mildly schizophrenic paranoia might be of value in  a diplomatic career. Tourette's in itself probably has advantageous aspects, if only because a hell of a lot of such folk are often surprisingly good at song and dance, and competitive ball sports. They can build their unpredictable motor patterns into their repertoire of movements.

LW: So in an evolutionary context you could say that there are two ways of explaining it. One is that there would have been some kind of adaptive advantage in the evolutionary past, which is no longer with us; the other is that contemporary relatives may also have a competitive advantage in certain contexts, with a low genetic 'dose'?

JB: Exactly. Evolutionary arguments provide you with a different type of explanation. This argument goes back to the classic case of sickle cell anaemia –
a single dose of the gene may be maintained in the population because it protects you from malaria, but every so often a double dose leads to the serious problems that we see with this condition. You could make exactly the same argument for these neurodevelopmental disorders. You can't of course make it for the degenerative diseases.

LW: In addition to being a neuropsychologist with an interest in human evolution you have also spent a lot of your time studying ancient rock art in northern Australia and looking into ancient artefacts from around the world. Is this a separate field of interest or do you feel your work here provides an insight into the human mind and evolution?

JB: I think it has to. We can learn a lot about the culture and cognitive abilities of our ancestors from the things they left behind. In particular we can gain a lot from studying the tools that are preserved. We also have a window on worlds past through the art and aesthetics of our ancient ancestors from their rock and cave art. Take the Acheulian hand axes that were found in France and elsewhere. These symmetrical pear-shaped objects were produced by Homo erectus. A hand axe gives us insight into the guy who was around at the time. These hand axes were made by a creature living perhaps a million years ago and with a brain probably about half our size, but these are in fact incredibly beautiful and bloody difficult things to make, and people say why did they make these incredibly beautiful hand axes? Maybe they weren't hand axes at all – maybe they arose through sexual selection, like the peacock's tail. Perhaps males of Homo erectus were saying 'look, I can make these bloody good axes – I'll be a good father for your kids!'

LW: So you think that the females of Homo erectus may have had a sense of aesthetics over a million years ago?

JB: I think they may well have had, or at least a sense of good workmanship. In fact in terms of a sense of aesthetics you can go even further back than that to Homo habilis. This little creature with the brain of the size of a chimp collected pebbles that happened to look like the female form perhaps 2.5 million years ago. That has to give you some sort of insight to the foundations of art and of human cognition and emotional responses. So knowledge of artefacts and of how evolutionary processes work can perhaps give us some insight into their cognitive and emotional abilities.

LW: And all of this interest can be traced back to having your chips wrapped in old copies of The Lancet?

JB: Yes, it's strange the bizarre, fortuitous events that set us off on these pathways in life.

John Bradshaw is Emeritus Professor at Monash University, Victoria, Australia.
E-mail: [email protected].