One of the most influential concepts in 21st-century neuroscience is the default mode network (DMN) — a set of brain regions that becomes more active when a person is doing nothing in particular, mind-wandering, remembering the past, or imagining the future. Originally described as the brain's "task-negative" circuit, the DMN has since been understood as the substrate for self-referential thought, autobiographical memory, and social cognition. In schizophrenia, the DMN does not behave as it should — and this has emerged as one of the most reliable functional abnormalities in the disorder.
In schizophrenia, the default mode network shows hyperconnectivity within itself at rest and reduced deactivation during cognitive tasks, with these abnormalities present at first episode and linked to positive symptoms, cognitive impairment, and abnormal self-experience.
What the DMN is
The default mode network was named by Marcus Raichle and colleagues in 2001 after they noticed a consistent pattern in fMRI data: certain brain regions reliably decreased their activity during external cognitive tasks compared with passive rest. The core DMN regions include:
- The medial prefrontal cortex
- The posterior cingulate cortex and precuneus
- The angular gyrus / inferior parietal lobule
- The medial temporal lobe (hippocampus and parahippocampus)
These regions are tightly intercorrelated when the brain is at rest. They support self-referential processing, autobiographical memory, mentalising about other minds, and prospection (imagining the future).
What goes wrong in schizophrenia
Two broad patterns have been replicated in schizophrenia DMN research:
1. Hyperconnectivity at rest
Resting-state fMRI studies generally show increased functional connectivity within the DMN in schizophrenia, particularly between medial prefrontal and posterior cingulate regions. This pattern has been reported in multiple meta-analyses and is present in first-episode patients and individuals at clinical high risk for psychosis.
2. Reduced task deactivation
During cognitive tasks, the DMN normally deactivates — quieting down so that task-positive networks can take over. In schizophrenia, this deactivation is often reduced. The DMN does not switch off as it should when external attention is required. This failure has been linked to working memory deficits and to the intrusion of self-referential thought into goal-directed activity.
Why this matters for symptoms
The DMN findings have clear face validity for several core features of schizophrenia:
- Aberrant self-experience. Schizophrenia involves disturbances of basic self-awareness — thoughts feeling not one's own, the boundary between self and world becoming porous. The DMN is the brain's self-referential circuit. Hyperactivity here is consistent with these phenomenological reports.
- Hallucinations. Auditory hallucinations have been linked in some studies to the DMN's interaction with auditory cortex — internally generated material being misattributed as external.
- Negative symptoms. Anhedonia and avolition involve a failure to anticipate and pursue future rewards. Prospection depends on the DMN.
- Cognitive symptoms. If the DMN cannot deactivate during tasks, attention to external information suffers.
The triple network model
One useful framework is Vinod Menon's "triple network" model, which proposes that three large-scale networks — the DMN, the central executive network, and the salience network — interact to support normal cognition, and that schizophrenia involves dysfunction in their dynamic switching. The salience network (centred on the anterior insula and dorsal anterior cingulate) is thought to act as a switch, toggling between internally focused (DMN) and externally focused (executive) modes. In schizophrenia, this switching is disrupted. See our piece on the salience network.
What replication looks like
Resting-state fMRI findings have been heavily scrutinised over the past decade. Some specific DMN findings replicate strongly; others have proved more variable across samples and analytic pipelines. The broad pattern — increased intra-DMN connectivity and reduced task deactivation — has held up across multiple meta-analyses, though effect sizes are smaller than initially reported. Standardised, large-cohort studies are increasingly the norm.
DMN and antipsychotics
Antipsychotic medications appear to partially normalise some aspects of DMN connectivity. Studies in first-episode patients before and after treatment show shifts toward control patterns, though normalisation is incomplete. Whether DMN changes track clinically with symptom improvement is an active research question.
DMN and psychotherapy
There is interesting overlap between schizophrenia DMN abnormalities and the brain effects of mindfulness training, which reduces DMN hyperactivity in healthy volunteers. Whether mindfulness or related practices can favourably modulate DMN function in schizophrenia is being studied. Our mindfulness for psychosis article reviews the clinical evidence.
What the DMN story does not explain
DMN abnormalities are not specific to schizophrenia. Similar patterns appear in major depression, autism, Alzheimer's disease, and chronic pain. The DMN is a circuit that is sensitive to a wide range of pathologies. Its abnormality in schizophrenia is real and important, but it is part of a broader pattern of large-scale network disruption rather than a unique signature.
Press coverage of "your default mode network on drug X" or "the meditation brain" often overstates the precision and clinical implications of DMN research. The findings are real but probabilistic and not yet clinically actionable at the individual level.
The bottom line
The default mode network is a self-referential circuit that is hyperconnected at rest and underdeactivated during tasks in schizophrenia. These abnormalities link biology to phenomenology — to the disturbances of self, attention, and prospection that characterise the disorder. The DMN is one of three large-scale networks (alongside the central executive and salience networks) whose dynamic interaction appears disrupted in schizophrenia, and understanding the network-level picture has reshaped how the field thinks about the illness.
This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a qualified mental health professional. If you or someone you know is in crisis, call or text 988 in the US, or your local emergency number.