The real causes of depression beyond antidepressants

One in four people will go through a major depressive episode in their lifetime, yet the dominant model for treating depression has remained unchanged for decades: identify the symptoms, assign a diagnosis, and prescribe a drug. Dr. James Greenblatt, a functional psychiatrist with over thirty years of clinical experience, proposes a paradigm shift: depression is not a Prozac deficiency — it's a signal that something in the body is not working properly.

The flawed "chemical imbalance" model

For decades, mainstream psychiatry explained depression as a simple serotonin deficit. More recent studies show that antidepressants perform no better than placebo for mild to moderate depression. At least one third of patients do not respond to medication, and those who do often continue experiencing symptoms.

The problem is not just efficacy but the approach itself: the system diagnoses using the DSM and medicates without asking why. Two people with the same depression diagnosis may have entirely different root causes and need entirely different interventions.

The root causes psychiatry tends to overlook

Nutrient deficiencies

More than 90% of Americans are deficient in at least one key nutrient. Vitamin D, zinc, magnesium, folate, vitamin B12, and omega-3 fatty acids are essential cofactors for neurotransmitter synthesis. Research published in 2025 shows direct associations between low vitamin D and zinc levels and suicide risk. Variants of the MTHFR gene, which regulates folate metabolism, are particularly common in patients with treatment-resistant depression.

The gut-brain connection

Gut dysbiosis is linked to virtually every major psychiatric disorder: depression, anxiety, Alzheimer's disease, and anorexia. When the digestive system is not functioning well, it also fails to absorb the micronutrients the brain needs. Gluten sensitivity, even without a celiac diagnosis, can produce brain inflammation and full psychiatric symptoms that disappear when gluten is eliminated.

Hormones, metabolism, and toxins

Hypothyroidism, low testosterone, estrogen-progesterone imbalance, and insulin resistance are common causes of depression that are rarely evaluated in a standard psychiatric consultation. Toxins such as mercury and excess copper also impair brain function. Chronic inflammation, triggered by stress, insufficient sleep, infections, or ultra-processed food, is the common denominator across many of these pathways.

Functional diagnosis: test, don't guess

Greenblatt argues that psychiatry cannot be practiced without knowing the patient's biomarkers. The basic panel he recommends includes vitamin D, B12, B6, folate, zinc, magnesium, homocysteine, copper, omega-3s, precursor hormones such as pregnenolone and DHEA, a complete thyroid panel, sex hormones, gut microbiome analysis, gluten sensitivity testing, inflammatory markers, insulin resistance indicators, and heavy metal screening. Additional tools include genetic testing (MTHFR), amino acid and fatty acid levels, and hair mineral testing for lithium.

The logic is simple: without data, any treatment is a guess.

Antidepressants: limitations and how to safely discontinue them

Antidepressants have a place in severe depression, but they should not be the only resource. One of Greenblatt's most valuable findings is that patients who cannot stop antidepressants without severe discontinuation syndrome (brain zaps, suicidal thoughts, emotional instability) improve dramatically when the underlying nutrient deficiencies are corrected first. The brain, adapted to medication over years, can rebalance more easily when it has the cofactors needed for serotonin synthesis.

A particularly striking finding is the role of nutritional lithium (lithium orotate, at doses of 2 to 5 mg): a 2025 study published in Nature showed that the brains of Alzheimer's patients have low lithium levels, and that lithium orotate can prevent and even reverse amyloid pathology in animal models.

An integrative approach

Greenblatt does not dismiss any tool: psychotherapy, medication when needed, trauma work, and correction of the underlying biological imbalances are all part of the same arsenal. The key is that this arsenal is used in a personalized way, based on each patient's data rather than their diagnostic category.

Conclusion

Depression affects more than 300 million people worldwide. Moving from a "diagnose and medicate" model to an "evaluate and treat the root cause" model is not alternative medicine — it is where decades of accumulated evidence points. Greenblatt's approach offers a concrete roadmap for anyone suffering from depression to access a truly personalized recovery plan.