When it isn’t only depression

Psychiatric symptoms are the end of a story, not the beginning. Low mood, anxiety, brain fog, irritability and exhaustion are how the body reports that something is wrong — but they do not tell you what is wrong. A number of medical conditions produce symptoms that are indistinguishable from depression, anxiety, or ADHD in a fifteen-minute appointment.

This matters because treatment aimed at the wrong target rarely works well. Someone with untreated sleep apnea may fail three antidepressants before anyone asks how they sleep. Someone with low ferritin may be told their exhaustion is depression. The medication was not the problem; the question was.

What can look like a psychiatric illness

None of these are exotic. All of them are common, and all of them are checkable.

• Thyroid disease. An underactive thyroid can produce low mood, cognitive slowing, weight change and fatigue; an overactive one can produce anxiety, agitation, tremor and insomnia. Both are routinely mistaken for primary psychiatric illness.
• Iron deficiency, with or without anemia. Low ferritin causes exhaustion, poor concentration and restless legs. In adults it is frequently read as depression; in adolescents it is frequently read as ADHD.
• B12 and folate deficiency. Both are associated with depressed mood, memory complaints and irritability, and both are more likely in people on long-term acid-suppressing medication, on metformin, or eating a plant-based diet.
• Obstructive sleep apnea. One of the most under-recognized contributors to treatment-resistant depression. Fragmented sleep produces low mood, irritability, cognitive impairment and blunted response to antidepressants.
• Hormonal transitions. Perimenopause, postpartum shifts and low testosterone all affect mood, sleep and anxiety, and are often dismissed or treated as psychiatric illness alone.
• Insulin resistance and metabolic dysfunction. Blood sugar instability affects energy, concentration and mood regulation — the territory of metabolic psychiatry.
• Inflammation and autoimmune conditions. Inflammatory illness is associated with depressive symptoms and fatigue through mechanisms that have nothing to do with mood in the ordinary sense.
• Vitamin D deficiency. Common at this latitude, particularly through a Pacific Northwest winter.
• Medication side effects. Corticosteroids, some hormonal contraceptives, beta blockers, isotretinoin and others can produce mood and anxiety symptoms that resolve when the medication is changed.
• Alcohol, cannabis, stimulants and caffeine. Regular use — including use that feels moderate — reshapes sleep, anxiety and mood in ways that are easy to attribute to something else.

Less often, but importantly, symptoms can arise from conditions such as Cushing's or Addison's disease, celiac disease, seizure disorders, or autoimmune encephalitis. These are uncommon. They are also the ones most costly to miss.

Wilson's disease: when psychosis has a physical cause

Wilson's disease is a rare inherited disorder in which the body cannot clear copper properly. Copper accumulates — in the liver, in the cornea, and in the deep structures of the brain that govern movement, mood and thought.

What makes it matter here is that psychiatric symptoms are frequently the first thing to appear, sometimes years before any liver or neurological problem is recognized. Roughly a third to half of people with Wilson's disease have psychiatric symptoms at presentation, and a substantial number are treated for a primary psychiatric illness first.

It can look like almost anything: personality change, irritability and impulsivity, depression, and in some cases frank psychosis with hallucinations and paranoia that is genuinely indistinguishable from schizophrenia in the room. A young adult who becomes psychotic in their late teens or twenties fits the expected picture of schizophrenia so precisely that there is often no obvious reason to look further.

Certain things should prompt a closer look:

• Onset before roughly age 40, particularly in adolescence or early adulthood.
• Any neurological sign alongside the psychiatric picture — tremor, clumsiness, stiffness, slurred or slowed speech, difficulty with handwriting, or an unusual gait.
• Unexplained liver abnormalities, including liver enzymes that were flagged and never explained.
• Unusually severe movement side effects from antipsychotic medication. People with Wilson's disease are notably sensitive to these, and a dramatic reaction to a standard dose is a meaningful signal.
• A sibling or parent with liver disease or an unexplained neurological illness.

Screening is straightforward: a serum ceruloplasmin level, a 24-hour urinary copper collection, and a slit-lamp eye examination looking for the copper ring that can form at the edge of the cornea.

The reason to care about a rare disease is what happens when it is found. Wilson's disease is treatable — copper can be removed and blocked from reaccumulating — and treatment can substantially improve or resolve psychiatric symptoms that had been attributed to a lifelong illness. Untreated, it progresses and can be fatal. It is one of the few genuinely reversible causes of psychosis in medicine, which is precisely why it is worth keeping in mind even though most people who ask about it will not have it.

We are not suggesting that psychosis is usually a copper problem. It is not. But a young person with new psychosis, a tremor, and an odd liver panel deserves the question asked.

Why this gets missed

Not through carelessness. A fifteen-minute medication visit is not built for it. There is time to ask how you are doing and adjust a dose — there is no time to take a sleep history, review your labs, ask what changed in the year before symptoms started, or notice that the fatigue began before the sadness did.

Root-cause work is mostly a function of time. It requires a longer first appointment and a willingness to ask questions whose answers might point away from a prescription.

How we approach it

• A comprehensive first evaluation that covers physical health, sleep, nutrition, substances, medications, hormonal history and life context — not only symptoms.
• Laboratory work when clinically indicated — thyroid studies, ferritin and iron studies, B12 and folate, vitamin D, metabolic markers, inflammatory markers.
• Pharmacogenomic testing when medications have failed or caused unusual side effects, to understand how you metabolize them.
• Treating what we find — and coordinating with your primary care provider or a specialist when something belongs in their hands rather than ours.
• Treating the psychiatric illness too, when it is there. Finding a contributor does not mean the depression is not real.

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