Does Pollen Make Bipolar Depression Worse?

Allergic reactions could worsen mental illnesses

/ Author:  / Reviewed by: Robert Carlson, M.D

Do allergic reactions affect bipolar depression? Could an immune reaction to pollen compromise one's mental health?

A team of curious researchers has set out to find if there is a connection.

There are a fair number of disorders and conditions associated with depression already: obesity, alcoholism, stress, anxiety, diabetes, schizoaffective disorders and the like.

Pollen is not nearly so often suggested as a contributing element or risk factor. Many people hardly notice pollen at all.

"Consult with a ear/nose/throat specialist if your allergies act up."

Pollen is, of course, well known as sometimes interfering with respiration. The itchiness and swelling and other symptoms of allergies should be understood as the body's way of coping with an influx of foreign bodies in the lungs.

The immune system becomes activated and produces chemical signaling, manifesting as symptoms such as sniffles and watery eyes, to a feeling of reduced mental energy.

While such reactions may be unpleasant, these symptoms represent the body's immune system sending waves of special molecules to recognize the invader as not part of the body, and to envelop it using different systems. In other words, the symptoms can be thought of as a sign of a healthy immune response, though this can get out of hand and become dangerous.

Why would respiratory and immune reactions be associated with bipolar depression?

To understand how feelings of sadness and low energy might be related to breathing in airborne plant particles, it helps to know how modern views of health have evolved.

Scientists are still teasing out many of the fascinating details about the interactions of the immune system, the hormone and endocrine signaling molecules of the body, and the brain. An ambitious label for these would be "psycho-neuro-immunology", but the key point to remember is that mood and emotion and psychological state are now believed by many scientists and physicians to affect and be affected by immune system reactions, such as allergies.

21st century science is seeking to measure the precise ways that emotional experience, brain states, hormonal signaling, and immune system reactions are interrelated. 

Dr. Partam Manalai and colleagues set out to investigate how much of an effect that the high pollen season could have on bipolar depression.

They examined 100 subjects experiencing either major depressive disorder or bipolar disorder to learn how exposure to pollen might change emotional state. The team's data suggests that "the exacerbation of allergic symptoms correlated significantly with a worsening in the depression scores".

Manalai and colleagues write that "...the findings of the current study suggest that worsening of depression in sensitized individuals during peak pollen seasons is not related only to severity of physical symptoms in allergic reaction, and thus is unlikely to be a mere reaction to a physical illness".

While the study focused on the response of people with bipolar disorder or major depressive disorder to the high pollen season, it is possible that people not suffering from these particular conditions who are exposed to high pollen load could also experience more depression as well.

These data are suggestive of a link between mood disorders and the allergic immune response. While the actual mechanism by which breathing in pollen might make people coping with bipolar depression more depressed is not currently known, the emotional reactions to allergies may turn out to be as important as the physical symptoms.

While much remains to be learned, allergy sufferers would be well advised to monitor how their emotional states may vary relative to pollen-triggered immune reactions.

The research was published in the February 2012 edition of the journal Bipolar Disorder. The authors of the paper did report any commercial associations that might pose a conflict of interest.

Reviewed by: 
Review Date: 
June 18, 2012
Last Updated:
April 18, 2013