How often do you catch yourself ruminating on something that happened yesterday, worrying about a meeting you have tomorrow, or simply lost in thought? Our guess is fairly frequently. And in our normal waking state, that’s to be expected – it’s our Default Mode Network (DMN) in action.
The DMN is the part of the brain that’s linked to introspective mental activities such as rumination, self-reflection, self-criticism, and mind wandering. While a certain level of this is to be expected in all of us, an increased focus on the self – accompanied by an overactive DMN – is correlated with mental health conditions such as depression, anxiety, and OCD.
So where do psychedelics come in? A body of research has emerged that shows that psychedelics such as LSD, magic mushrooms, and DMT reduce activity in the DMN, and heavily impact our sense of self during those experiences.
Changes in the DMN are associated with some of the typical experiences with psychedelics: feeling like the barriers between ourselves and the external world are more blurred; overwhelming feelings of interconnectedness; and experiences of ego dissolution. These changes are also related to the feeling of relief from depressive symptoms in the weeks and months following a psychedelic journey, as that area of the brain has been given a chance to ‘reset.’
In this article, we’ll discuss what the DMN is, how it’s linked to mental health, the impact of psychedelics on the DMN, and how this contributes to a new frontier for mental health.
What is the Default Mode Network?
The DMN is a group of brain regions that are most active during reflective, absent-minded, introspective thought.1 All the time we spend dwelling on the past, worrying about the future, and engaging in self-criticism is correlated with high levels of activity in the DMN. Activity in the DMN is also linked to a high level of self-awareness, i.e., the ego.
These functions are essential to everyday consciousness and are most present when a person is in a resting state. But as soon as you give that person a specific task to devote their attention to, such as a puzzle or math problem, the DMN becomes less active and the Task Positive Network (TPN) starts to light up.
This continuous sense of self begins to emerge at around the age of five, as a child starts to develop their “ego.” And it’s not without reason: self-focus and the ability to differentiate ourselves from the world around us has been vital for our evolution and is crucial to everyday functioning. However, when the balance starts to shift, problems may arise, as overactivity in the DMN is linked to a number of mental health conditions.
The Default Mode Network and Mental Health
We’ve all been there – we say something silly, trip over in public, or crack a bad joke. While everyone around us likely forgets about this minor event within minutes, we spend hours after-the-fact worrying about how that moment reflected badly on us. It’s not surprising, then, that researchers have found links between an overactive DMN and high scores for conditions like depression and anxiety.
People that suffer from depression and anxiety often engage in excessive rumination and self-reflection, something that is linked to hyperactivity in some regions of the DMN. One study found that the connectivity of the anterior portions of the DMN, which are involved in self-referential and emotional processes, was positively correlated with anxiety and depression scores.2
Researchers have also found links between those who suffer from OCD and have overactive or disrupted regions of the DMN. In one study, patients with OCD were found to have abnormalities in the neural systems of the DMN associated with self-referential processing.3
In essence, how our DMN functions has a lot to do with the amount of focus we put on ourselves, and subsequently, the length of time we spend ruminating about how we are perceived in the world.
Psychedelics and the Default Mode Network
According to Robin Carhart-Harris, Professor of Neurology and Psychiatry and Director of the Psychedelics Division, Neuroscape, UCSF, the default mode network “seems to be the best candidate that we have for the biological underpinnings of the sense of self.”4
When we take psychedelics such as magic mushrooms, LSD, and ayahuasca, this sense of self is often reduced or dissolved entirely. So, as you might imagine, neuroimaging studies show that these substances reduce activity in the area of the brain that arguably ‘powers’ the ego – the DMN. One 2015 study found that ayahuasca (which contains DMT) caused a significant decrease in most parts of the DMN,5 while another found reduced connectivity in the DMN in participants who took MDMA.6
In a state of ego loss, much of the self-focus that harbors negative thought patterns is dissolved. Boundaries between ourselves and the world around us come down, and we see ourselves as interconnected entities rather than a sole individual that’s disconnected from nature and other beings.
This loss of there being an ‘I’ – the ego being hushed – is strongly linked to lower DMN activity levels. One study which explored the effects of LSD on the DMN found that the weaker the integrity of the DMN, the stronger the loss of self.7
In many cases, taking these psychedelics can be described as ‘pushing the reset button’ as patients are freed from the control of the negative thought loops. As a result, they have an opportunity to reconsolidate these negative thought patterns and well-traversed pathways that had previously contributed to their depressive symptoms. This was the case in a 2016 study on psilocybin for treatment-resistant depression, where participants’ depression symptoms were markedly reduced three months after the high-dose treatment.8
One way of describing this effect is to imagine a ski slope with deep grooves where skiers have made their marks throughout the day. If the ski slope is your brain, psychedelics effectively act as a fresh snowfall – evening out all of those deep grooves (or rigid ways of thinking) to level out the slope and make it easier for you to take a new track. In this sense, they allow us to start afresh, build new habits, and see ourselves and the world around us in a different light – without a self-critical ego there to sow seeds of doubt.
A New Frontier For Mental Health
With psychedelic-assisted therapy showing increasing therapeutic promise, we can expect further developments in the field that bring hope to those suffering from psychiatric conditions. As research on compounds like psilocybin, LSD, DMT, and MDMA continues, the psychedelic landscape will continue to shift, stigmas shed, and legal restrictions lift.
While certainly no magic bullet, psychedelic-assisted therapy presents a novel paradigm for mental health. Often acting as a reboot to the brain, when used in a properly guided session, psychedelics can produce incredible results for people with psychological conditions like depression and anxiety. While there’s more research to be done, we can safely assume that the effect of psychedelics on the DMN plays an important role in their therapeutic potential.
1. Andrews-Hanna, J. R. (2011). The Brain’s Default Network and Its Adaptive Role in Internal Mentation. The Neuroscientist, 18(3), 251–270. https://doi.org/10.1177/1073858411403316
2. Coutinho, J. F., Fernandesl, S. V., Soares, J. M., Maia, L., Gonçalves, S. F., & Sampaio, A. (2015). Default mode network dissociation in depressive and anxiety states. Brain Imaging and Behavior, 10(1), 147–157. https://doi.org/10.1007/s11682-015-9375-7
3. Beucke, J. C., Sepulcre, J., Eldaief, M. C., Sebold, M., Kathmann, N., & Kaufmann, C. (2014). Default mode network subsystem alterations in obsessive–compulsive disorder. British Journal of Psychiatry, 205(5), 376–382. https://doi.org/10.1192/bjp.bp.113.137380
4. Anderson, A. (2016, April 13). LSD May Chip Away at the Brain’s “Sense of Self” Network. Scientific American. https://www.scientificamerican.com/article/lsd-may-chip-away-at-the-brain-s-sense-of-self-network/
5. Palhano-Fontes, F., Andrade, K. C., Tofoli, L. F., Santos, A. C., Crippa, J. A. S., Hallak, J. E. C., Ribeiro, S., & de Araujo, D. B. (2015). The Psychedelic State Induced by Ayahuasca Modulates the Activity and Connectivity of the Default Mode Network. PLOS ONE, 10(2), e0118143. https://doi.org/10.1371/journal.pone.0118143
6. Müller, F., Holze, F., Dolder, P., Ley, L., Vizeli, P., Soltermann, A., Liechti, M. E., & Borgwardt, S. (2020). MDMA-induced changes in within-network connectivity contradict the specificity of these alterations for the effects of serotonergic hallucinogens. Neuropsychopharmacology, 46(3), 545–553. https://doi.org/10.1038/s41386-020-00906-2
7. Carhart-Harris, R. L., Muthukumaraswamy, S., Roseman, L., Kaelen, M., Droog, W., Murphy, K., Tagliazucchi, E., Schenberg, E. E., Nest, T., Orban, C., Leech, R., Williams, L. T., Williams, T. M., Bolstridge, M., Sessa, B., McGonigle, J., Sereno, M. I., Nichols, D., Hellyer, P. J., . . . Nutt, D. J. (2016). Neural correlates of the LSD experience revealed by multimodal neuroimaging. Proceedings of the National Academy of Sciences, 113(17), 4853–4858. https://doi.org/10.1073/pnas.1518377113
8. Carhart-Harris, R. L., Bolstridge, M., Rucker, J., Day, C. M. J., Erritzoe, D., Kaelen, M., Bloomfield, M., Rickard, J. A., Forbes, B., Feilding, A., Taylor, D., Pilling, S., Curran, V. H., & Nutt, D. J. (2016). Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study. The Lancet Psychiatry, 3(7), 619–627. https://doi.org/10.1016/s2215-0366(16)30065-7