Perhaps the era of psychotropic drugs has reached its peak and its slow twilight is approaching. While record prescriptions are still being written, a radically new approach to understanding and treating mental illness is emerging from the abyss of neurology. The enormous effort of researchers is no longer focused on developing new pills, but on changing the functioning of specific nerve circuits through physical intervention in the brain.
The brightest indication that drugs are beginning to be seen as a thing of the past is the little-known fact that nearly all major pharmaceutical companies are shutting down or substantially reducing their drug development programs for mental and neurological disorders. The fact – or rather its realization – that there had been virtually no genuine innovation in this area since the 50s, when the basic classes of psychotropic drugs in use were developed, made sales prospects look bleak. Of course, new drugs have appeared regularly in the last five decades, often with less severe side effects but not much more effective in most cases.
This is largely because these drugs are not very specific about their effects on the brain. For example, the drug fluoxetine (better known as Prozac) alters the levels of the neurotransmitter serotonin in the brain’s mood-responsive networks, but has the same effects on the networks involved in sexual responses, leading to the common side effect of having difficulty reaching orgasm.
The pharmaceutical holy grail has long been a drug that would be more selective in effect, but the industry has abandoned this multi-billion dollar dream as being too complicated to implement.
Instead, science comes in that focuses on understanding the brain as a series of networks, each of which supports a different aspect of our experience and behavior. In such an analysis, our brain is a bit like a metropolis: it is impossible to understand the whole without knowing how districts interact with each other. Few of Shankill’s Belfast residents spend money on Falls Road, and that tells us a lot more about the city – as I mentioned key Loyalist and Republican strongholds – than the information that the median income in both areas is similar. By analogy, knowing that key regions of the brain interact differently when someone becomes depressed tells us something important that could be missed when measuring average brain activity.
According to this idea, we can better understand complex human emotions and behaviors by understanding neural networks. This is what the new wave of interest in neuroscience is focusing on. This surge of interest is not focused on the concept itself, well known since the mid-twentieth century, but on the extent to which research and therapies focus on the desire to identify and modify key brain circuits.
Huge sums have been spent on this. The Obama administration has pledged $ 3 billion to develop technology to help identify brain circuits, and the US National Institute of Mental Health has pledged it will shift seven-figure funding from research into conditions such as schizophrenia and depression to a system that checks how the brain’s circuits contribute to the difficulty. common in various ailments. This project, with the ineffective name of Research Domain Criteria, is intended to eventually replace the diagnostic systems used by today’s psychiatrists.
Perhaps more surprising for some is the explosion in the number of deep brain stimulation (DBS) treatments where electrodes are placed in the patient’s brain to alter the activity of specific neural circuits. Medtronic, one of the manufacturers of such devices, reports that its pacemakers have been used in over one hundred thousand patients. In most cases, these are well-studied and proven treatments for Parkinson’s disease, but are increasingly being used in clinical trials for a wider range of ailments. Recent research has examined how deep brain stimulation can be used to treat pain, eating disorders, addiction, control aggression, improve memory, and intervene in a variety of other behavioral problems.
New technologies such as optogenetics suggest it may control the brain’s circuits even more subtly. While DBS works by stimulating an organ with electrical flows, optogenetics involves placing a mild virus into the neurons that contains information about light-sensitive proteins. Then the brain cells themselves become sensitive to light and their activity can be controlled thanks to millisecond flashes of light emitted by appropriately placed optical fibers. So far, the effectiveness of this method has only been demonstrated in animals, but it has raised great hopes that it could lead to the development of carefully controlled therapies in humans where only carefully selected brain circuits were affected.
Let’s face it: the scientific revolution in identifying and manipulating brain circuits is underway. Moreover, with the billions allocated to research over the next 10 years, we are bound to witness a medical revolution in the coming decades. But there will also be an even more important change. Advances in neuroscience are not just about discoveries. This science also shapes our perception of ourselves. The Prozac generation will fade into the shadows, while the emergence of an empire of people treating the brain’s circuits, discussing freely at lunch in pseudoscientific neurological jargon.
These are all tools to help us understand humanity as a species, but not our humanity. The pain of losing a loved one or the joy of fulfilling life’s desires can never be explained only by the operation of the brain’s circuits.