How a blood test can tell if you’re depressed, bipolar, or just a miserable human being

Finding out if something is wrong with your brain is a laughably primitive process. There are questionnaires instead of blood tests, interviews instead of scans. And if you do manage to convince a doctor that something isn’t right, there’s a decent chance you’re going to be misdiagnosed.

It’s an embarrassment for the doctors and advocates who constantly tell you that a mental health diagnosis is no different from any other condition. It feeds into the skepticism around mood disorders and allows your friends to roll their eyes and your insurance company to deny your claims.

Researchers at Indiana University hope to change all that by diagnosing depression and bipolar disorder with a simple blood test. Mood disorders could be pre-screened just like heart problems or kidney function, taking subjectivity entirely out of the mix and adding a layer of legitimacy to disorders still regarded with skepticism (regardless of all the “It’s OK To Not Be OK” campaigns).

Why are mood disorder blood tests needed?

After suffering through high school with undiagnosed something or other, I finally wanted to figure out why I’d be stuck in bed for days one week and organizing (and executing) a cross-country road trip the next.

I called my doctor and was told it would take a few weeks to get an appointment because it wasn’t an emergency. I mentioned that sometimes I wanted to jump out of my 12th storey window, but they weren’t all that impressed and told me to go to the mental hospital before jumping.

I went to the hospital. I waited two hours, and someone came and asked me some questions. A doctor came and five minutes later sent me home with a prescription for Paxil and a depression diagnosis. It’s an easy label to apply, and I was happy enough to go home and take the pills.

But, 70 per cent of people with bipolar disorder are misdiagnosed with depression. Most of them won’t get a proper diagnosis for 10–20 years after their first interaction with medical professionals. And guess what? Antidepressants are terrible for most people with bipolar — they keep the depressive side of manic depression down but push manic symptoms higher.

Awkward.

How does it work?

You have biomarkers in your blood. A biomarker is anything in your body that can be measured. Reflexes are biomarkers, so are blood pressure readings. In blood, it refers to substances that are present in a cell when weird things are going on inside them. Once you see what’s happening in a cell, you can figure out what substances may help treat the disorder.

“Through this work, we wanted to develop blood tests for depression and for bipolar disorder, to distinguish between the two and to match people to the right treatments,” said Dr. Alexander Niculescu, a psychiatry professor at the university’s school of medicine. “Blood biomarkers are emerging as important tools in disorders where subjective self-report by an individual, or a clinical impression of a healthcare professional, is not always reliable. These blood tests can open the door to precise, personalized matching with medications and objective monitoring of response to treatment.”

It would look something like this — you get a blood test and find out you have clinical depression. A deeper read of your blood says you’re likely to respond to a certain medicine. You take medicine. You feel better. Your blood confirms everything is working the way it’s supposed to because the biomarkers indicating a problem aren’t present.

Better drugs, better outcomes

Anyone who has decided to take drugs to improve their mental condition — something I support unequivocally — knows how hard it sucks to find something that works. Everyone is different, and what works for one person won’t work for another.

Here’s an example.

• When I was in my early 20s, I took Paxil. It gave me super bursts of productivity, but it also made me twitchy. I took it for a few years before the shakiness became too much, and it was a bitch to come off because of the withdrawal (which doctors insisted didn’t exist back then).
• In my early 40s, I went onto Lexapro to deal with anxiety and depressive symptoms. It made me super angry all the time, so we switched to Zoloft.
• That worked fine. A few years ago, I moved to Scotland, and my symptoms worsened, particularly anxiety. So the doctors kept increasing my dose.
• Came home following a nervous breakdown. The new doctor realized I wasn’t depressed but bipolar. Antidepressants are terrible for folks with bipolar, so I’ve been trying to wean off Zoloft. I started by cutting to 100mg, then 50 mg, now 25 mg. I’ve gone very slowly to avoid withdrawal.
• I was then given Seroquel, an antipsychotic prescribed at 25 mg for people who have medication-resistant insomnia. I was up to 200 mg a day on my way to 350 mg, but the drowsiness was too much (I was sleeping about 17 hours a day), and we slowly worked our way back down to nothing.
• Lamotrigine was next, starting at 25 mg and working up to at least 200 mg. You need to go slowly because some people develop a rash that kills them. That’s less than ideal, but so far, so good.
• The Zoloft increased anxiety, so we added some Ativan to take that edge off as needed and increased the Zoloft.
• Increasing the Zoloft led to hypomania a few weeks ago, so we added 500 mg/day of lithium to get me back to balance. We’ll stay with this unless/until it starts eating my kidneys or melting my thyroid, and then try something else.

It’s clear that so much depends on individual chemistry, and that’s what this study addresses. Wouldn’t it be nice to know that you’ll develop a flesh-eating rash BEFORE you take the drug? It would also be nice to know if your kidneys would explode while on a drug. This exists in all kinds of medical situations, but not for mood disorders.

Is that everything fixed then?

For many of us who have found understanding and hope through a diagnosis, the idea of a clinical confirmation will likely be a little daunting. What if everything we’ve believed turns out to be a misunderstanding? If you test negative but are still struggling, what then?

Mental health problems aren’t solely cured with medicine, if you can say they could be cured at all. There will be plenty of people who fall just outside of a blood test’s range who are still struggling, just like there are plenty of people struggling now who would say they are depressed but fall outside of clinical definitions.

And this is early-stage research. We won’t be getting customized drugs just yet. Still, the doctors think this will lead to better treatment.

“Blood biomarkers offer real-world clinical practice advantages,” he says. “The brain cannot be easily biopsied in live individuals, so we’ve worked hard over the years to identify blood biomarkers for neuropsychiatric disorders. Given the fact that 1 in 4 people will have a clinical mood disorder episode in their lifetime, the need for and importance of efforts such as ours cannot be overstated.”

Unfortunately, there’s no blood test to determine whether the doctor was joking when he said it wasn’t easy to dissect human brains while the human is still alive. There’s also no test for over-inflated self-importance.

But hopefully, there’ll soon be tests for bipolar and depression.

You can read the entire study here, though a lot of it is super research-y.

And there’s a Hamlet quote, if you’re into that sort of thing.