Hidden Causes of Depression that Standard Bloodwork Often Misses

Depression, of which major depressive disorder (MDD) is the most common form, is a serious mental health condition that negatively impacts how you feel, think, act, and view the world around you.

A 2023 Gallup poll found that 29% of adults were diagnosed with some form of depression during their lifetime, while about 18% were experiencing symptoms at the time.

Depression is more common in women and older adults, but it often first appears during the late teen years into a person’s mid-20s.

At Sidhu Psychiatric Clinic, board-certified psychiatric mental health nurse practitioner Kanwaljit “Kavi” Sidhu, NP-C, PMHNP-BC, and our staff diagnose and treat all forms of depression at our Palm Harbor, Florida, office.

While a simple blood test can detect potential indications of depression, such as altered neurotransmitter or hormone levels, standard bloodwork can’t serve as a definitive diagnosis, in part because it isn’t designed to assess all factors.

What causes depression?

Researchers aren’t certain of the exact causes of depression, but they believe it may stem from a variety of factors, including:

Biological differences

People with depression have structural changes in their brains, which can show up on some forms of imaging. Doctors don’t fully understand the significance of these changes, but researchers hope they may eventually help pinpoint a definitive cause.

Altered brain chemistry

Neurotransmitters are chemical messengers in the brain that carry signals between the various nerves. Research indicates that changes in the transmitters’ levels (especially serotonin, glutamate, and norepinephrine), how these messengers function, and how they interact with the different brain areas involved in regulating mood may play a significant role in causing depression, as well as determining how effective a given treatment may be.

Hormones

Changes in the levels of various hormones may trigger depression in some people. For example, rapidly changing hormone levels play a role in postpartum depression, an episode of depression that follows giving birth. Thyroid problems and the changing availability of thyroid hormones can also lead to depressive symptoms.

Genetics

While researchers currently don’t know which gene(s) plays a role in depression, they know that people who have blood relatives with the condition are more likely to develop the condition themselves.

Common depression symptoms

Symptoms of depression vary from one person to another and can range anywhere from mild to so severe it disrupts your daily life. Some common symptoms are:

• Feeling sad, empty, and/or hopeless
• Becoming irritable or angry, even with small things
• Losing interest in activities you once enjoyed
• Eating too little or too much, accompanied by weight loss or gain
• Sleeping too little or too much
• Feeling listless or fatigued
• Feeling worthless or excessively guilty
• Difficulty thinking or concentrating
• Trouble making minor decisions
• Increasing thoughts of death or suicidal ideation

If you or someone you know is thinking of suicide, contact the suicide prevention lifeline at 988.

Why a blood test can’t detect depression

Depression is a clinical diagnosis, meaning that no single standard test can confirm or refute it. Doctors primarily use bloodwork to rule out other causes of your symptoms, such as thyroid issues or vitamin deficiencies that mimic depression. The true signs of depression are a combination of psychological, behavioral, and physical indicators.

Causes of depression standard bloodwork misses

Since doctors don’t know the gene or genes responsible for triggering depression, no blood test can reveal if genetics is one of the causative factors of your condition.

There are also no blood tests for negative thoughts, suicidal ideation, loss of interest in once-pleasurable activities, feeling worthless, or difficulty making even the smallest of decisions.

A mental health specialist, such as Kavi and our team at Sidhu Psychiatric Clinic, needs to perform comprehensive psychological and behavioral tests in addition to blood tests in order to arrive at a clinically relevant depression diagnosis.

Once we’ve evaluated all the possible factors, we can determine the best way to treat you to relieve your symptoms. Usually, we use a combination of psychotherapy and medication management.

If you or a loved one is experiencing depression symptoms, our team at Sidhu Psychiatric Clinic can help. Call our office at 727-382-1383 to schedule a consultation, or contact us online today.