Common antidepressents are less effective at high altitudes, rodent study suggests

May 31, 2018, University of Utah
Credit: CC0 Public Domain

Three common antidepressants – Paxil (paroxetine), Lexapro (escitalopram), and Prozac (fluoxetine) – could be less effective at high elevations, suggests research involving lab rats and led by scientists at University of Utah Health.

When rats were placed in conditions that simulate moderate-high altitudes, the three pharmaceuticals failed to suppress behaviors that model human . By contrast, another antidepressant, Zoloft (sertraline), worked under these conditions. The results of tests with the four drugs – all of which fall in the class of antidepressants known as serotonin reuptake inhibitors (SSRIs) – are published in the May online edition of Pharmacology, Biochemistry and Behavior.

"Being at altitude can worsen levels of depression and lower the response to SSRIs," said Shami Kanekar, research assistant professor of psychiatry and lead author on the study. "We may need to be more careful about which antidepressants are prescribed to people living at altitude." Future studies will need to determine if these selective effects of SSRIs in animals are also seen in people.

Previous work has shown links between living at higher altitudes and susceptibility to depression. Rates of depression and suicide are particularly high in Utah and other states in the Intermountain West region of the United States where elevations are considerably higher than in the rest of the country. Similar trends are also seen in countries such as Austria and Peru that have large populations living at high elevation.

Connections between altitude and depression have also been documented in tests with where conditions can be carefully controlled. Kanekar found that rats acclimated to 4,500 feet, or in hypobaric chambers mimicking conditions at 10,000 feet, were more likely to display depression-like behaviors than those in chambers calibrated to sea level conditions. Depression was evaluated by validated methods, including the inclination to swim and climb.

The current study adds an important element to the discussion by demonstrating that of four SSRIs tested, only Zoloft significantly and consistently lessened signs of depression seen at altitude. Moreover, there were clear differences between females and males in both antidepressant response and depression-like behavior at altitude.

Despite being within the same class of antidepressants, individual SSRIs have different pharmacological profiles, potentially explaining their varied effects.

"Utah has very high rates of both depression and anxiety. In many instances, long-term treatment is required but does not work well," says the study's senior author Perry Renshaw, professor of psychiatry. "This work suggests that only some antidepressants are likely to be effective at altitudes higher than 2,000 feet."

While the current study investigated short-term impacts of the drugs and changes in altitude, it remains to be determined whether responses to also differ over the long-term in people.

If the findings hold true, they could also have implications for individuals with diseases that affect breathing such as asthma, sleep apnea, and chronic obstructive pulmonary disease (COPD). These so-called hypoxic conditions lower amounts of oxygen in the bloodstream, mimicking impacts of low oxygen environments at . Patients with these conditions are also susceptible to increased rates of depression and suicidal behavior.

In addition to Kanekar and Renshaw, Chandni Sheth, Hendrik Ombach, Paul Olson, Olena Bogdanova, Matthew Petersen, Chloe Renshaw, Young-Hoon Sung, and Kristen D'Anci are authors on the study.

Explore further: Thin air, high altitudes cause depression in female rats

More information: Shami Kanekar et al. Hypobaric hypoxia exposure in rats differentially alters antidepressant efficacy of the selective serotonin reuptake inhibitors fluoxetine, paroxetine, escitalopram and sertraline, Pharmacology Biochemistry and Behavior (2018). DOI: 10.1016/j.pbb.2018.05.002

Related Stories

Thin air, high altitudes cause depression in female rats

March 26, 2015
In a novel study, University of Utah (U of U) researchers have shown that hypobaric hypoxia (the reduced oxygen experienced at high altitude) can lead to depression.

Could living at high altitude increase suicide risk? Evidence suggests possible treatments

March 10, 2018
High-altitude areas—particularly the US intermountain states—have increased rates of suicide and depression, suggests a review of research evidence in the Harvard Review of Psychiatry.

Male depression may lower pregnancy chances among infertile couples, study suggests

May 17, 2018
Among couples being treated for infertility, depression in the male partner was linked to lower pregnancy chances, while depression in the female partner was not found to influence the rate of live birth, according to a study ...

Insights into depression could aid development of new treatments

February 26, 2018
Fresh insights into changes in the brain linked to depression could pave the way for new therapies.

Do antidepressants lead to chronic use?

January 3, 2018
Data from Netherlands point to the chronic use of antidepressant drugs in general practice in a study published in the current issue of Psychotherapy and Psychosomatics. Antidepressant use is highly prevalent. Research has ...

Depression and anxiety may reduce chances of IVF pregnancy

March 7, 2016
Depression and anxiety, and not necessarily the use of antidepressant medication, are associated with lower pregnancy and live birth rates following in vitro fertilisation, according to a large register study from Karolinska ...

Recommended for you

Suicide risk in abused teen girls linked to mother-daughter conflict

October 18, 2018
Teenage girls who were maltreated as children are more likely to entertain suicidal thoughts if the relationship with their mother is poor and the degree of conflict between the two of them high.

Study shows how bias can influence people estimating the ages of other people

October 17, 2018
A trio of researchers from the University of New South Wales and Western Sydney University has discovered some of the factors involved when people make errors in estimating the ages of other people. In their paper published ...

Infants are more likely to learn when with a peer

October 16, 2018
Infants are more likely to learn from on-screen instruction when paired with another infant as opposed to viewing the lesson alone, according to a new study.

Researchers use brain cells in a dish to study genetic origins of schizophrenia

October 16, 2018
A study in Biological Psychiatry has established a new analytical method for investigating the complex genetic origins of mental illnesses using brain cells that are grown in a dish from human embryonic stem cells. Researchers ...

Income and wealth affect the mental health of Australians, study shows

October 16, 2018
Australians who have higher incomes and greater wealth are more likely to experience better mental health throughout their lives, new research led by the Bankwest Curtin Economics Centre has found.

Study suggests biological basis for depression, anxiety, sleep disturbances in older adults

October 15, 2018
UC San Francisco researchers, in collaboration with the unique Brazilian Biobank for Aging Studies (BBAS) at the University of São Paulo, have shown that the earliest stages of the brain degeneration associated with Alzheimer's ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.