Depression can strike anyone, at any age, regardless of race, gender or practically any other demographic marker you can name. Major depression is one of the most common mental disorders in the U.S., according to the National Institute of Mental Health, or NIMH.
In 2015, about 16.1 million Americans ages 18 or older — that’s 6.7 percent of all U.S. adults — had at least one major depressive episode in the past year. What’s more, about 5 percent of all Americans will be diagnosed with depression in their lifetime, and the number of undiagnosed cases is likely much higher than that.
[See: Am I Just Sad– or Actually Depressed?]
So what makes an individual susceptible to depression? Mental health experts have homed in on several factors that seem to increase the risk. The Mayo Clinic lists the following:
— Personality traits like low self-esteem or pessimism.
— Stressful life events, including the death of a loved one or financial difficulties.
— Childhood trauma, like sexual or emotional abuse, or a history of childhood or teenage depression.
— Family history of depression, other mental health issues, alcoholism or suicide.
— Being gender-nonconforming and in a nonsupportive family.
— History of eating disorders or PTSD.
— Certain health problems such as cancer, stroke, chronic pain or heart disease.
— Taking some medications, including high blood pressure medications or sleeping pills.
The American Psychiatric Association, or APA, divides depression risk factors into four categories: biochemistry, genetics, personality traits and environmental factors.
Biochemistry
The ways in which certain brain chemicals function may predispose someone to depression. Chemicals called neurotransmitters help regulate how electrical signals pass from one brain neuron to another, and several, including dopamine and serotonin, have been shown to play a role in mood regulation. Many drugs used to treat depression target these very chemicals.
Sometimes, other diseases, such as Parkinson’s and stroke, may cause chemical or structural changes in the brain that might have a direct role in depression. Illness-related anxiety and stress can also trigger symptoms of depression. And for some, the medications taken for these illnesses and others may carry side effects that cause or exacerbate depression.
In seasonal affective disorder, or SAD, a lack of vitamin D — which is produced in the body primarily by exposure to sunlight — has been deemed a culprit. “SAD is a real thing, and in Iceland they have a higher incidence of depression,” says Carl Tishler, a private practitioner and adjunct associate professor of psychiatry and psychology at The Ohio State University. “Here in Ohio, we have a lot of dog days of no sunlight. Light therapy can be very effective for certain people. Just getting outside and being exposed to sunlight charges one’s batteries.”
[See: Seasonal Affective Disorder: 8 Ways to Feel Better.]
Genetics
Depression can run in families, which suggests a genetic component to the disease. Research has yet to identify which genes are at play, but statistical data bear out the link. When one identical twin has depression, for instance, the other has a 70 percent chance of developing the illness sometime in life.
“My theory is, we all have a set of genes, and the depression gene, if there is such a gene, gets nicked or cut or damaged by something,” Tishler says. “Whether it’s war trauma, a car accident, childhood abuse, something causes that to become part of the individual’s psyche. Some people go through war trauma and come out pretty good, but a lot don’t, which is why we are seeing an inordinate amount of suicide in war vets today.”
Depression often coincides with other illnesses, both mental and physical in nature. The initial disease can cause depression, and likewise depression can influence the course of the disease. Depression is common among people who have chronic illnesses such as:
— Cancer.
— Coronary heart disease.
— Diabetes.
— Epilepsy.
— Stroke.
— Alzheimer’s disease.
— HIV/AIDS.
— Parkinson’s disease.
— Systemic lupus erythematosus.
— Rheumatoid arthritis.
Personality Traits
Though depression can happen at any age, it often begins in teens or young adults. The NIMH reports that most chronic mood and anxiety disorders in adults begin as high anxiety in children, noting that high levels of childhood anxiety could beget a higher risk of adult depression.
People with low self-esteem, who are easily overwhelmed by stress or who are generally pessimistic appear to be more likely to experience depression, the APA says. Alison Ross, a practicing psychologist and adjunct associate professor at City College of New York, adds that those who are especially sensitive to loss are also vulnerable. “People aren’t born sensitive,” she says. “I think it probably comes from the family dynamic. Something goes on in the home life of the child that contributes to that predisposition. There is a relational predisposition to a sense of abandonment or loneliness from the loss of relationship. Even a rejection of friendship can be a precipitating factor in depression.”
[See: 11 Simple, Proven Ways to Optimize Your Mental Health.]
Environmental Factors
Many mental health experts believe that environmental stressors play a significant role in tipping those who are vulnerable toward clinical depression. The NIMH says that continued exposure to violence, neglect, abuse or poverty may make some people more susceptible to depression. So can events such as physical or emotional trauma, the loss of a loved one, financial difficulties, relationship problems, trauma that occurred in childhood and, in fact, any stressful situation.
Here’s how that might manifest. “Say you lose your dog as a child,” Ross explains. “When you try to talk about it, the reaction [from the parents or guardians] is, ‘It’s just a dog. Stop crying.’ There is no system of dialog to help the child mourn the loss and process it. I think they grow up as adults with problems losing things that matter and not knowing how to work through loss.” Such a loss in adulthood, she says, could trigger depression.
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What Are the Risk Factors for Depression? originally appeared on usnews.com
