MDMA THERAPY

How LSD therapy may strengthen white matter tracts in depression

In recent years, research into psychedelic therapy has shifted from merely “what someone experiences” to “what measurably changes” in the brain. A new article in Cell Reports Medicine adds an interesting piece to this puzzle: in people with depression, changes appear to be visible in the white matter, a type of connectivity network in the brain, following treatment with a moderate to high dose of LSD. The study reports that these changes are associated with a decrease in depression symptoms in the weeks following treatment.

Findings of this kind raise understandable questions. What exactly is white matter? What does “integrity” of white matter mean? Does this say anything about how psychedelic therapy works? And how far can we go in drawing conclusions based on a single study? In this article, we outline the core of the research, place it in context, and discuss what it does and does not mean for practice.

White matter in depression: why this topic is relevant

The brain consists roughly of gray matter (where many cell bodies are located) and white matter (bundles of nerve fibers that connect different brain regions). You can view white matter as “highways” for information traffic. In the context of depression, scientific literature has long described connections between symptoms and changes in networks involved in emotion regulation, stress processing, and cognitive control. Some of these findings concern functional cooperation (for example, how areas are active simultaneously), but there are also meta-analyses pointing to structural differences in white matter tracts in people with major depressive disorder (MDD).

The new LSD study is interesting because it focuses on a concrete, measurable aspect of that structure: the microstructure of white matter. If treatment not only temporarily “activates” something in perception or mood, but is also linked to changes in connectivity at the structural level, this could eventually help to better understand mechanisms, protocols, and aftercare. At the same time, it is important to remain cautious: a correlation in brain measurements is not automatically proof of cause and effect.

What exactly did this study investigate?

The researchers wanted to know whether LSD causes changes in the microstructure of white matter in people with MDD, and whether those changes are related to the progression of depression symptoms in the weeks that follow. In a broader sense, psychedelics are often linked to “neuroplasticity,” an umbrella term for the brain’s ability to adapt. However, hard, in vivo evidence in humans, measured using imaging, is still scarce.

Sixty-one patients with MDD participated in this randomized study. They received either a low dose (2 times 25 micrograms) or a moderate to high dose (first 100 micrograms, later 200 micrograms) of LSD. Diffusion tensor imaging (DTI) was performed on 35 participants before and after the intervention. DTI is an MRI technique that can provide information about the direction and consistency of water diffusion in brain tissue. A commonly used measure within DTI is fractional anisotropy (FA). Briefly, FA is often interpreted as an indicator related to the “orderliness” or integrity of white matter tracts, but it is not a direct measurement of a single biological process.

Important detail: the study focused primarily on structural changes in the brain and their relationship to symptom progression, not on the “trip narrative” as the main subject. This makes it a valuable addition to studies that primarily analyze psychological processes and subjective experiences.

The most important results in plain language

The key finding: in the moderate to high dose group, FA increased significantly in multiple white matter areas often involved in emotion regulation and limbic connections, including the internal and external capsule, the sagittal stratum, and the fornix/stria terminalis. This effect was not observed in the low dose group. The reported effect size in the DTI subgroup was large (Cohen's d around 1.48), and virtually all participants in the high dose group showed an individual increase.

In addition, the researchers found that the degree of FA increase was statistically associated with a reduction in depressive symptoms at 2, 6, and 12 weeks after treatment, measured using standard questionnaires (IDS-C and IDS-SR). This association persisted after adjustment for baseline depression severity.

A striking detail is that certain subjective experience types, such as “oceanic boundlessness” and mystical-like experiences, did not correlate with FA changes. In a regression analysis, subjective effects actually predicted symptom improvement more strongly than white matter changes. This suggests that experience and measured brain change may make parallel, partially independent contributions. Therefore, it is not the case that “more FA” simply equates to “more healing” or “deeper experience”.

Anyone who wishes to read the study themselves or compare the summary with the source can do so via this page: New Cell Reports Medicine study: LSD-induced neuroplasticity in white matter in depression.

What does “more FA” actually mean, and what doesn’t it?

FA is often used as an indicator of white matter properties, but it is an indirect measure. Higher FA can be associated with multiple underlying factors, such as changes in myelination, axonal organization, density, or fiber coherence. At the same time, FA can also be influenced by geometric factors, noise, and the complexity of intersecting fiber bundles. This means that “FA rising” does not directly imply that literally “new cables” have been laid or that white matter is “recovering” in an unambiguous way.

Furthermore, the direction of the association remains uncertain in this study. The authors themselves state that it cannot be definitively established whether the increase in FA is a direct effect of LSD on white matter microstructure, or whether it is (partly) a secondary effect of symptom improvement, for example due to changes in sleep, activity, or stress physiology. A third possibility is that both processes influence each other: psychological change, behavior, and neurobiology can enter a feedback loop.

The value of this research therefore lies not in a simple conclusion (“LSD repairs white matter”), but in opening a testable hypothesis: in depression, psychedelics could, under certain circumstances, be measurably associated with structural changes in networks relevant to emotion regulation.

How does this fit into the broader picture of psychedelic therapy?

In the debate surrounding psychedelic therapy, the emphasis often lies on meaningful experiences, emotional breakthroughs, new perspectives, and the processing of difficult memories. This research reminds us that there may also be measurable biological traces running parallel to the clinical course. This can help to make the field less black and white. It is not a matter of either “only chemistry” or “only psychology.” It can be an interplay in which setting, guidance, expectations, personal history, and neurobiological vulnerability together determine what happens.

However, it is still too early to draw firm practical conclusions from this, for example regarding ideal dosage or whether it would be possible to predict who benefits based on a scan. The neuroimaging subgroup was relatively small (35 people, 17 of whom were in the high-dose group). Replication in larger and more diverse groups is essential, as is research into how long the measured changes persist.

Safety, context and harm reduction

According to the authors, the treatments in this study were well tolerated within the framework of a clinical trial (NCT03866252). No unexpected serious adverse events were reported that would explain the imaging outcomes. This is relevant, but it remains context-dependent: safety in research does not automatically imply that use outside of research has the same risk assessment. Factors such as screening, medical backup, purity and dosage, setting, and professional guidance play a major role in studies.

Context is also important from a legal and practical perspective. Psychedelic sessions involving substances such as LSD do not fall under regular healthcare in the Netherlands. Furthermore, regarding MDMA, sessions can currently only be discussed within the context of scientific research or in clinical practice within a harm-reduction context. From a harm-reduction perspective, the focus is not on encouraging use, but on minimizing risks as much as possible through honest information, preparation, guidance, and aftercare where possible.

Anyone considering therapy with psychedelics would generally do well not to look solely at “the substance,” but also at preconditions: screening and contraindications, set and setting, the integration plan, and what happens if a session becomes emotionally heavy. These are topics that are often strictly defined in research but can vary significantly in practice.

What can you, as a reader, do with this without drawing too many conclusions?

If you are struggling with depressive symptoms yourself, a study like this may sound hopeful, but it is wise to distinguish between hope and evidence. This is an interesting step in the mechanistic understanding of psychedelic therapy, but not a definitive answer. Much remains unknown: for whom does it work and for whom does it not, how sustainable are the effects, what role do expectation and therapy play, and how do structural changes relate to daily functioning and relapse prevention?

If you are primarily oriented towards guidance and responsible frameworks, it can be helpful to delve into how sessions are generally structured, what integration looks like, and what questions you can ask a facilitator. If you are looking for information about MDMA in a therapeutic context and how this is discussed within the current reality, you can read more about MDMA therapy on our website. This is not a substitute for medical care or individual advice, but can help to better understand the landscape, terminology, and safety principles.

Conclusion

This study reports that a moderate to high dose of LSD in people with depression is associated with measurable changes in white matter, and that these changes are statistically linked to symptom reduction up to 12 weeks after treatment. At the same time, it remains unclear exactly what is cause and effect, and how this translates to broader groups and the longer term. The finding is primarily an invitation for more, better, and larger research into the biological and psychological mechanisms of psychedelic therapy, with continued attention to safety, context, and realistic expectations.