Some years ago, the Harvard psychiatrist Leon Eisenberg commented that, in the course of his lifetime, his discipline had swung from the brainless psychiatry propounded by psychoanalysts to the mindless psychiatry of those enamoured of biological reductionism and neuroscience. 

Camilla Nord, who runs a neuroscience laboratory at Cambridge, is firmly a member of the latter camp. Though in a few places in The Balanced Brain she is driven to concede that social factors seem to play a role in mental health or mental distress, she immediately insists that ‘the process by which social factors are able to cause mental illness is entirely biological’. With the zeal of a true believer, she promises that she is going ‘to tell you what neuroscience reveals about how mental health works’.

By and large, she focuses her attention on depression and anxiety. Such major forms of mental illness as schizophrenia and bipolar disorder are mentioned glancingly on a handful of occasions (on five and three pages respectively) and receive no serious or sustained attention. That’s distinctly odd, given the social burden these illnesses bring in their train and the immense amount of attention they have drawn from the neuroscientific community. Nor is there any discussion of the reasons for their omission.  But, given Nord’s chosen focus, what does she have to tell us about the roots of depression and anxiety in the brain? How well does she substantiate her claim that these are purely diseases of the brain, and since she also wants to connect neuroscientific findings to effective forms of intervention, what does she have to offer on that front?

She places considerable emphasis on scanning technology as a source of information about what is happening in the brain.  She cites two sorts: Positron Emission Tomography or PET scans; and Functional Magnetic Resonance Imaging or fMRIs. But as she concedes, both these techniques have serious drawbacks. PET scans use a radioactive tracer to construct an image of approximately where in the brain neurons were active; fMRIs measure blood flow in the brain, but that rises and falls very slowly, whereas neural firing is practically instantaneous, ‘so fMRI cannot possibly keep up with the real speed of brain activity’.  Both approaches provide only indirect and extremely crude measures of what is occurring. The more precise of the two, fMRI, at best has a resolution of one cubic millimetre, which corresponds to about one million neurons. But as if that is not bad enough, Nord cannot provide any means of translating these laboratory measurements into thoughts and emotions. To move beyond the artificial setting of the laboratory where these scans are done to the complexity of daily life is likewise impossible.

In discussing the variability of human emotion and response, Nord consistently claims that these differences reflect differences in people’s brain circuits. Only about half of those treated with antidepressants improve. Why is that? Because the responders and non-responders’ brain circuits work differently. How do we know that? Because they respond differently. That sort of circularity should convince no one. Turning to psychological forms of treatment for depression, we learn that ‘CBT – and indeed all psychological therapies – are inherently biological: they work via changes in the brain’. Can Nord or anyone else actually show in convincing detail that this is so? Well no, actually, unless you are prepared to beg the question and assume that the brain is always and everywhere the prime mover, as Nord does.

To a quite extraordinary extent, Nord’s discussion is littered with speculation. I lost count of the number of times I was told that something ‘may’ have had a certain effect, ‘might’ be related to an observed outcome, or that ‘perhaps’ this theory explained what was going on. Here is a representative passage:

Maybe the particular neurobiological changes in emotional bias that antidepressants cause are only effective at changing mood in certain people… Other people, despite having the very same diagnosis, might not show this bias, and they might instead have a different neurobiology.

Perhaps. Then again, perhaps not.

Beginning with Arvid Carlsson’s 1957 discovery of dopamine’s role as a neurotransmitter, a whole new line of neuroscientific research opened up and we developed new understandings of the complexity of brain activity. Notably, there were attempts to explain mental illness by invoking a presumed deficit or surplus of a particular neurotransmitter. A shortage of serotonin was widely promoted as the cause of depression.  This speculation, and it was no more than that, proved a marketing bonanza for pharmaceutical houses. Unfortunately, as Nord acknowledges, ‘the central claim of a monoamine/serotonin deficit causing depression is now known to be wrong’ – and has been known to be so for nearly two decades. Yet it continues to circulate in popular culture. In its place, neuroscience has failed to come up with a plausible, let alone demonstrable, physical cause for depression or anxiety.

As for treatment, Nord suggests that patients should try antidepressants (though she concedes half of them won’t derive any benefit and largely neglects to discuss the side effects many suffer from). Or perhaps they should try psychotherapy. That might work, and will for some. That’s scarcely novel advice. Alternatively, what about diet, exercise or magic mushrooms? Here she concedes there is no real evidence of efficacy, but why not try them? They might fix a broken brain.

Finally, she touts the possible value of transcranial stimulation with electricity, or, in recalcitrant cases, deep brain stimulation, done by implanting electrodes in the brain. She mentions that when a controlled trial was done of the latter, it failed and was terminated early. Actually, there were two such trials, funded by two rival manufacturers, and both were stopped because of poor results, and in some instances devastating side-effects: brain infections, worsened psychiatric states, even a suicide. Bizarrely, Nord then cites the case of a single patient treated by an enthusiast for the approach as though it is reliable evidence in the therapy’s favour, when she must know that such anecdotal evidence is scientifically worthless.

In the middle of her discussion of neurotransmitters Nord tells a story about a conference she attended at which a celebrity uttered some platitudes about the wonders of the brain. She warns us:

Because of the seductive appeal of vague statements about the brain, individuals and organisations can lay claims based on the shakiest of foundations of experimental science, and people will listen. Be suspicious when you see this prefix, and be wary of ‘neurobollocks’.

Amen to that.