A couple of weeks ago headlines about research on electroconvulsive therapy (ECT) research in Aberdeen, Scotland, in which nine people (two-thirds of whom were men, a reversal of real life where over two-thirds of those undergoing ECT Scotland are women) had functional MRI scans before and after treatment spread round the world: Wirkungsmechanismus der Elektrokrampftherapie entdeckt; Investigadores escoceses anunciaron un gran avance en la comprensión de la terapia electroconvulsiva; etc. Almost all the media went with the “Scientists discover…” headlines and simply reprinted the press-release uncritically (uncritically as in the broadest sense of not even asking “what have we got here?”). A rare exception was the financial website Bloomberg who added “researchers say” to the usual headline about discovery and even thought to ring a psychiatrist not connected to the research – Associate Professor at Dartmouth Medical School Paul Holtzheimer (professional interests: functional and structural neuroimaging and focal neuromodulation techniques such as transcranial magnetic stimulation and deep brain stimulation). Associate Professor Holtzheimer said: ““If this study holds up, it tells us this is a network problem” and came up with an analogy of how the brain works:
“Understanding the connectivity is like understanding shipping routes. Counting the number of trucks in and out of Chicago gives a person a sense of what the shipping routes may be. However, when data such as the number of ships coming into San Francisco is known, and that is correlated with Chicago’s trucks, it gives a better understanding of how the routes work. This study begins to map Chicago and San Francisco for the brain’s connections, Holtzheimer said.”
There has of course never been a shortage of theories about how ECT might work. They have been around ever since 1938 when ECT was first used. Ten years later in 1948 Major Hirsch Gordon published an article entitled “Fifty shock therapy theories” in which he discussed 50 theories he had been able to glean from the literature about how the shock therapies (insulin, metrazol and electro) worked. “Some of them are independent, others overlap, but all challenge our attention”. (H.L. Gordon 1948 Fifty shock therapy theories Military Surgeon 103: 397-401)
The author divided the 50 theories into 27 somatogenic and 23 psychogenic. Number 1 somatogenic theory was simply physiologic – “a physiological action of a yet unknown type”. This theory has survived remarkably well down the decades and today you will find many accounts of ECT saying something similar – that the exact mechanism of action is not yet understood but that it is something physiological, rather than psychological, although nowadays psychiatrists would probably use the term biochemical rather than physiological. Numbers 2 and 3 likened shock therapy to psychosurgery, suggesting they worked by destructive processes or weakening of association tracts (“attention becomes directed more to the present, through the stimuli it provides, than to the past and its memories”). The latter bears a ressemblance to today’s theories of turning down connections. Number 4 was a vegetative effect, and explained why women had a better prognosis with shock therapy as they “show increased vegetative instability during the climacteric and menstruation”. Number 5 was to do with hormones. Most modern theories centre on brain biochemistry rather than hormones, but the hormone theory still has followers (for example American psychiatrist Richard Abrams). Number 6, the acroagonine theory, was the theory of Italian Ugo Cerletti who first used ECT and suggested that ECT “sets off a powerful diencephalic discharge that mobilizes all philogenetically organized mechanisms of self protection and self defense, resulting in the formation of a humoral substance – “acroagonine” that has actually been isolated from the brains of electroshocked animals”. Number 7 was the theory that started it all, the theory that there was some kind of natural antagonism between epilepsy and schizophrenia (at this point the author adds a note saying that this antagonism is no longer believed to be true). Numbers 8, 9, 22, 10, and 17 involved the circulation, autonomic nervous system and brain metabolism. The rather terse number 10, “Brain metabolism is affected”, is perhaps akin to modern theories about neurotransmitters. 11 was cell membranes, 12 the diencephalon and vegetative effects again, 13, relevant to insulin shock therapy, was reduced metabolism due to hypoglycaemia. 14 and 15 were something to do with oxygen, and 16 involved enzymes. Number 18, capillary spasms, was rather an interesting one: “It produces spasms in the brain capillaries and diseased nerve cells are eliminated”. The author doesn’t explain how healthy nerve cells are spared. Number 19, cortex depressed, “It produces a depressant effect and reduction of activity in the cortex”, seems a bit similar to the latest theory from researchers in Aberdeen. 20 was simply decreasing cerebral function, while 21, primitive centers, suggested that injuring some cells allowed others, in more primitive parts of the brain, to be more active. The therapeutic factor in number 23 was coma, in 24 irreversible changes in the cortex, in 25 electrolytes, in 26 intramuscular anoxia and finally in 27 structural changes in the hippocampus and ganglia.
The psychogenic theories can all be ignored because psychiatrists don’t believe in such things nowadays.
The author concluded that the usefulness of the shock therapies did not depend on the elucidation of their mechanism of action, pointing out that “many great drugs and curative methods began as (and some still are) empiricals”. But attempts to explain the mechanism should be encouraged because, the author continued: “not only do they satisfy the normal human curiosity for the cause of things, but they may widen their scope, discover new fields of applications and even new methods for the attainment of the same or better results”. Which isn’t much different from what they are saying in Aberdeen over 60 years on: “However if we understand more about how ECT works, we will be in a better position to replace it with something less invasive and more acceptable”.