What the "54% Remission Rate" Revealed: Depression Treatment Shifts from "Brain Chemicals" to "Personalized Medicine"

"Depression is caused by a deficiency of brain chemicals like serotonin."

This explanation is still widely used in general society. Of course, antidepressants that act on serotonin and norepinephrine have undoubtedly supported many patients. However, depression is not a disease that can be explained by a single cause. There are people who do not achieve sufficient improvement even with medication or psychotherapy, and even with the same diagnosis, symptoms, progression, physical characteristics, and response to treatment can vary greatly.

In this context, the treatment research that gained attention in 2026 targeted the immune system.

When the anti-inflammatory drug tocilizumab, used in the treatment of rheumatoid arthritis, was administered to patients with difficult-to-treat depression, 53.9% met the remission criteria about four weeks later. In the placebo group, it was 31.3%, highlighting the renewed attention on the "possibility of improving depression by suppressing inflammation."

However, it is premature to think that a groundbreaking treatment has been completed just by looking at this "54%" figure. What the research indicated was not the establishment of a treatment method, but the possibility that the immune system is deeply involved in some cases of depression.

The Target Was "Patients with Inflammation"

The trial conducted by the University of Bristol in the UK involved 30 adults with moderate to severe depression who did not achieve sufficient effects with existing antidepressants.

The important point is that this was not a study that simply gathered "patients with depression."

Participants were required to have a high-sensitivity CRP level in their blood above a certain value. High-sensitivity CRP is one of the indicators used to understand the inflammatory state in the body, and the test was conducted multiple times. Additionally, symptoms suspected to be related to inflammation, such as fatigue and physical symptoms, were included in the selection criteria.

Participants were divided into a group receiving a single infusion of tocilizumab, which inhibits the IL-6 receptor, and a placebo group receiving saline, with symptoms evaluated on days 7, 14, and 28.

At the final evaluation point, 7 out of 13 in the tocilizumab group met the remission criteria, compared to 5 out of 16 in the placebo group. The "treatment response rate," which indicates a certain level of symptom improvement, was also numerically higher in the tocilizumab group at 46.2%, compared to 18.8% in the placebo group.

Improvement trends were also reported in multiple symptoms such as fatigue, concentration, lack of energy, pessimism, and feelings of worthlessness.

Reasons Why "54%" Cannot Be the Sole Judgment

On the other hand, the research paper notes extremely important caveats.

Firstly, this trial was a "proof-of-concept study" involving only 30 people. It is not a large-scale trial to ultimately prove the drug's effectiveness but a stage to explore whether it is worth investigating in future research, which symptoms should be evaluated, and what level of effect can be expected.

Secondly, there was no clear intergroup difference in the physical symptoms set as the primary evaluation item in advance for 14 days after administration. Overall, the study was small in scale, so the main results did not reach statistical significance.

There is also significant uncertainty in the difference in remission rates. When converted to numbers, it is "7 people versus 5 people," and the percentages can change significantly with just a few different results. While the figure of 53.9% is factual, it cannot be generalized as a drug that works for "more than half of the patients."

Thirdly, tocilizumab is not a health supplement or a common painkiller. It is a biological agent that suppresses immune responses and is originally used for diseases like rheumatoid arthritis, with usage monitored for infections, liver function, blood cell counts, etc. Although no serious adverse events were reported in this small trial, the safety of long-term use in a larger patient population needs separate verification.

Therefore, it should not be interpreted as "suppressing inflammation will work for anyone's depression." There is no basis for self-medicating with over-the-counter anti-inflammatory drugs.

The Idea of Not Treating Depression as a Single Disease

The greatest significance of this study lies not in the drug itself but in the "method of selecting patients."

In some depression patients, chronic low-grade inflammation is observed. Substances called inflammatory cytokines may affect not only immune responses but also sleep, appetite, motivation, fatigue, and cognitive functions.

When the body is fighting an infection, strong drowsiness, fatigue, decreased appetite, and reduced activity occur. These are considered reactions to conserve energy, but if the inflammatory state persists for a long time, it may exacerbate symptoms similar to depression.

However, inflammation is not the cause of all depression.

Numerous factors, including strong psychological stress, experiences of loss, isolation, trauma, sleep disorders, genetic factors, chronic diseases, hormones, and changes in brain circuits, are intricately related. Inflammation is just one of those pathways.

Therefore, in the future, instead of trying the same drugs sequentially for patients diagnosed with the same "depression," it may be considered to choose treatment methods by combining inflammation markers, symptom characteristics, and past treatment responses.

In this study, it was suggested that those with higher high-sensitivity CRP might experience greater improvement than those with higher IL-6 concentrations before treatment. If reproduced in future trials, relatively accessible blood tests might become a clue for treatment selection.

Psychedelics Treatment Accelerated by Massive Acquisition

Alongside immunotherapy, the use of psychedelics in treatment has become a major topic in the field of mental health in 2026.

U.S. pharmaceutical giant Eli Lilly announced a deal to acquire AtaiBeckley, which develops new drugs for mental disorders, for up to $3.8 billion, including conditional payments.

The central candidate drug, BPL-003, is a nasal spray investigational drug based on 5-MeO-DMT. It is being developed for treatment-resistant depression and has received Breakthrough Therapy designation in the U.S., with Phase 3-related activities underway.

This massive investment indicates that psychedelics treatment has become a market where major pharmaceutical companies are seriously entering, not just a domain for some researchers and startups.

On the other hand, the scientific evidence is not straightforward.

In the EPIsoDE trial conducted in Germany with 144 patients with treatment-resistant depression, 25 milligrams of psilocybin were combined with psychotherapy. The percentage of those whose depressive symptoms decreased by more than 50% six weeks later was 17.0% in the 25-milligram group and 10.6% in the active placebo group, but this difference was not statistically significant in the primary evaluation item.

In secondary evaluations, such as the average change in symptom scores, results indicating clinically meaningful improvement were shown. However, reports of suicidal ideation on the day of administration and serious side effects, including persistent perceptual symptoms, were also reported.

In other words, psilocybin research is at a stage where it cannot be said to be "ineffective" or "already proven effective."

Moreover, what is being evaluated in psychedelics treatment is not just the ingestion of the substance. It includes a treatment package that encompasses pre-treatment preparation, a controlled environment, expert support during administration, and subsequent psychotherapy. There is no guarantee that the same effects and safety can be achieved when used by individuals in non-medical environments.

Muscle Supplements and Gut Bacteria Also Under Study

New possibilities are not limited to expensive biological agents and psychedelics. Research is also progressing on repurposing substances already used for other purposes for depression treatment.

One representative example is creatine, known as a sports supplement.

A systematic review published in 2026 analyzed five randomized controlled trials involving a total of 238 participants. In two of the five trials, adding creatine to standard treatment resulted in greater symptom improvement. Particularly, in a trial where female major depression patients combined the antidepressant escitalopram with 5 grams of creatine per day, the number of participants who achieved remission increased.

However, in the remaining three trials, no clear effect was confirmed. There are also biases such as a small number of participants and a high proportion of women. There were cases where hypomanic or manic states occurred in participants with bipolar disorder, so it is not necessarily safe because it is a common supplement.

Research has also been conducted on adding probiotics for depression in the elderly. In the PRODG trial involving 58 participants aged 60 and over, the group that added probiotics to standard antidepressant treatment for 12 weeks showed slightly greater improvement in depressive and anxiety symptoms than the placebo group.

However, both groups improved significantly over time, and no clear additional effect on quality of life was confirmed. This is also a study positioned as a preliminary stage before large-scale trials.

These results symbolize a trend of trying to comprehensively capture not only the brain but also cellular energy metabolism, immunity, gut bacteria, and neurotransmission.

New Drug with 14-Day Administration Appears in Japan

Changes in treatment methods are also beginning in Japan.

In December 2025, Shionogi & Co., Ltd. obtained manufacturing and marketing approval in Japan for "Zulzubae," which contains the active ingredient Zuranolone, targeting major depressive disorder in adults, and launched it in March 2026.

Zuranolone is a neuroactive steroid that modulates the function of GABA-A receptors. It has a different mechanism of action from many traditional antidepressants and was approved as a treatment method involving once-daily administration for 14 days.

In a domestic Phase 3 trial, the depression symptom score on day 14 improved significantly compared to placebo. However, the average difference between the groups was not large, and points to consider in actual clinical practice include the sustainability of the effect, timing of re-administration, and responses to drowsiness and dizziness.

Nevertheless, the emergence of an option different from the method of taking the same drug daily for several months to years indicates a diversification of treatment design.

Drugs Alone Cannot Save Patients

While new drug research is attracting attention, in mental health care, even if a drug is approved, it is meaningless if patients cannot receive treatment.

In the Czech Republic, reforms are underway to shift from a system centered on long-term hospitalization in large psychiatric hospitals to support by community-based multidisciplinary teams. A plan to establish about 100 mental health centers by 2030 has been presented.

In the centers, psychiatrists, psychologists, nurses, social workers, and others collaborate to support not only medical care but also housing, employment, administrative procedures, family relationships, and community life. Initial evaluations have reported a decrease in the number of hospitalization days and an increase in people who can continue living in the community.

Since depression is a disease that is prone to recurrence and affects the entire life, strengthening only the effects of drugs will not solve problems such as isolation, unemployment, economic difficulties, living environment, and access to medical care.

Innovative treatments and familiar, continuous support systems are not choices between one or the other.

Expectations and Cautions Intersect on SNS

 

The anti-inflammatory drug research attracted attention on SNS and online forums.

On forums dealing with science news, there were perceptions such as "It's hopeful to be able to treat patients who didn't respond to conventional drugs through a different pathway" and "It's a study that supports the idea that there are multiple types of depression."

On the other hand, questions were also posted, such as "Is it really superior to common SSRIs?" "Does using the headline '54% in a study of 30 people' not cause misunderstanding?" and "What about the infection risk and cost of drugs that suppress the immune system?"

Particularly noticeable is the concern about the confusion between remission rate and cure rate.

In medical research, remission refers to a state where symptoms have fallen below a certain standard at the evaluation point. It does not mean that the disease will not recur in the future or that the disease has completely disappeared. Expressing it as "54% cured" would give an impression different from the research content.

In posts about psychedelics, there are testimonials from people who have experienced treatment-resistant depression, saying "It was more helpful than other treatments" and "It became a turning point to rebuild my life." On the other hand, posts also emphasize that the effects are not permanent, undesirable experiences can occur, and expert management is necessary.

There is also strong dissatisfaction with access issues, such as "Even if treatments with expected effects are researched, patients cannot use them due to approval, cost, and lack of medical institutions."

While these posts are earnest voices from those involved, testimonials on SNS do not substitute for clinical trials. This is because there is a possibility that those who felt the effects are more likely to post, and issues such as confirmation of diagnosis, dosage, and combination treatments cannot be verified.

What the 2026 Research Really Indicates

The words that symbolize depression research in 2026 are "diversification," not "panacea."

Different pathways are being considered, such as targeting the immune system for those with strong inflammation, treatments that promote neuroplasticity for specific patients, drugs acting on the GABA system for short-term effects, and methods that supplement energy metabolism and gut-brain interaction.

This does not mean that traditional antidepressants will become unnecessary. It suggests the possibility of adding new options to current treatments, including psychotherapy, existing drugs, electroconvulsive therapy, transcranial magnetic stimulation, ketamine-based treatments, and life support.

The 54% figure for tocilizumab is not a confirmed treatment outcome. However, it indicates the need to investigate biological pathways different from those previously considered, rather than deeming those who did not respond to antidepressants as "untreatable."

The next focus will be whether the effects can be reproduced in large-scale trials, which patients will benefit, whether it is safe in the long term, and whether it is cost-effective compared to existing treatments.

Having hope and carefully verifying are not contradictory.

Rather than consuming the "54%" as a miraculous number, the era is beginning where depression is not explained by a single cause or a single