When we feel depressed, we are more likely to get stuck in cycles of repetitive ruminative thoughts that have a negative emotional tone. We may regret the past, judge ourselves as unworthy or unlovable, blame others for our problems, or anticipate a bleak future. These ruminative cycles exacerbate feelings of sadness, shame or anger, and interfere with motivation to try to move on or actively solve problems. Depressive thought cycles like these seem to be entrenched, and are very difficult to break, even when we try to use logic to refute the negative thinking. Ruminative thinking makes depression worse and is even a predictor of subsequent depression in non-depressed people and of relapse in previously depressed people.
Recently, scientists at Stanford University have begun to uncover what might be going on in our brains during depressive rumination. A July 2015 study, “Depressive Rumination, the Default-Mode Network, and the Dark Matter of Clinical Neuroscience,” authored by J. Paul Hamilton and colleagues was published in the journal Biological Psychiatry. This study statistically combined several previous research studies using meta-analytic tools and came to the conclusion that depressed people had increased functional brain connections between two different brain areas:
The DMN is a part of the brain that is active when we self-reflect, worry, daydream, or reminisce. It has been described as facilitating a wakeful state of rest in which the mind naturally wanders. The DMN refers to a network of interacting brain regions including the posterior cingulate cortex (PCC), anterior cingulate cortex (ACC), and ventral prefrontal cortex (PFC).
The subgenual PFC helps to direct the DMN towards reflecting on and trying to solve the problems which the brain considers most pressing or important for survival. This process can be functional if such reflection actually leads to finding new answers or taking effective action.
In depression, the subgenual PFC seems to go haywire, hijacking normal self-reflection into a state of mind that is negative, self-focused, and withdrawn. In this state of mind, we continually reflect on our problems in a repetitive, negatively-toned way, but are de-motivated to actually engage with the world so as to solve those problems. Depressed people tend to go on and on talking about themselves and their problems, yet seem mentally stuck and unable to move forward. The fact that they can’t just “snap out of it” is consistent with the idea that a dysfunctional brain network may be involved in depressive thinking.
Some preliminary research shows that this intervention may change abnormal functional connectivity within the DMN.
It doesn’t matter whether it’s tidying your closets, doing the laundry, or doing a crossword puzzle, getting an “on-task” focus can de-activate the DMN and instead activate the “on-task” areas of the brain.
A 2015 study by Bratman and colleagues from Stanford University, published in the journal Proceedings of the National Academy of Science found that for healthy participants, a 90-minute walk in a natural setting, decreased both ruminative thinking and neural activity in the subgenual prefrontal cortex whereas a 90-minute walk in an urban setting had no such effects on either rumination or neural activity. In other words, walking in a natural environment seems to open up your thinking in a way that lessens the grip of the faulty brain network.
Deliberately focusing your attention on what you are seeing, hearing, feeling, sensing, or smelling right now, can help your brain get out of an automatic mind-wandering state and de-activate the DMN. Instead, you focus mindfully on your direct experience in the present moment, which activates the “on-task” network.
Mindfulness meditation is a practice that can teach you to gain control of the focus of your attention—to be more aware of what you are thinking about and able to redirect your focus. In one small study (Brewer et al.) that scanned the brains of novice and experienced meditators, the experienced meditators showed less DMN activation and reported less mind-wandering during three different meditative activities (like watching the breath or doing a compassion meditation).
Melanie Greenberg, Ph.D., is a practicing psychologist in Mill Valley, California, and former professor in the Ph.D. program at the California School of Professional Psychology. She is an expert on stress, the brain, and mindfulness. She provides workshops, speaking engagements, and psychotherapy for individuals and couples. She regularly appears on radio shows and as an expert in national media. She also does in-person and long-distance coaching for executives and entrepreneurs. Her new book, The Stress-Proof Brain was released in 2017.
Gregory N. Bratman et al. Nature experience reduces rumination and subgenual prefrontal cortex activation PNAS 2015 112 (28) 8567-8572 (doi:10.1073/pnas.1510459112)
Brewer et al. Meditation experience is associated with differences in default mode network activity and connectivity (PNAS article off web: www.pnas.org/cgi/doi/10.1073/pnas.1112029108)
Hamilton, J. Paul et al. Depressive Rumination, the Default-Mode Network, and the Dark Matter of Clinical Neuroscience. Biological Psychiatry , Volume 78 , Issue 4 , 224 - 230