Depression Causes Print Causes and Risk Factors of Depression By Nancy Schimelpfening Updated August 10, 2019 Medically reviewed by a board-certified physician Depression Overview Types Symptoms Causes & Risk Factors Diagnosis Treatment Coping ADA & Your Rights Depression in Kids Depression can affect anyone at almost any age. The reasons why some people grow depressed is not always known. Researchers suspect there are actually many different causes of depression and that it is not always preventable. Overview Verywell / Joshua Seong Depression is one of the most common mental disorders in the United States. It is estimated that 10 to 15 percent of the general population will experience clinical depression in their lifetime. And the World Health Organization estimates 5 percent of men and 9 percent of women experience depressive disorders in any given year. There are a number of different things that can cause depression ranging from biological to environmental. Some things that can raise your risk for depression include: A family history of depression. You are more likely to experience symptoms of depression if others in your family also have depression or another type of mood disorder.Certain medical conditions. You may be more likely to experience depression if you have a chronic illness, sleep disorder, and thyroid conditions. Depression rates also tend to be higher among people who have chronic pain, diabetes, multiple sclerosis, and cancer.Substance use. Having a history of substance use or misuse can also increase the likelihood of depression. Other factors that may play a role include childhood trauma, medications, life stress, poor self-esteem, and some medications. How Is Depression Diagnosed? Genetics and Biology Twin, adoption, and family studies have linked depression to genetics. While studies suggest that there is a strong genetic component, researchers are not yet certain about all the genetic risk factors for depression. Most researchers suspect that having parents or siblings with depression may be a risk factor for depression. It is still unclear exactly which genes play a role in depression and other mood disorders, but researchers do know that there are many different genes that can play a role. By better understanding how they function, gene researchers hope to be able to create effective treatments. Researchers have found that having a parent and grandparent with depression doubles the risk of depression. Estimates suggest that depression is approximately 40% determine by genetics. Brain Chemistry Imbalances Another potential biological cause of depression is an imbalance in the neurotransmitters which are involved in mood regulation. Certain neurotransmitters, including dopamine, serotonin, and norepinephrine, play an important role in mood. Neurotransmitters are chemical substances which help different areas of the brain communicate with each other. When certain neurotransmitters are in short supply, this may lead to the symptoms we recognize as clinical depression. This theory of depression suggests that having too much or too little of certain neurotransmitters causes, or at least contributes to, depression. While this explanation is often cited as a major cause of depression, it remains unproven and many experts believe that it does not paint a complete picture of the complex factors that contribute to depression. Medications to treat depression often focus on altering the levels of certain chemicals in the brain. Some of these treatments include selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors (MAOIs), and tricyclic antidepressants (TCAs). Other Risk Factors There are also a number of lifestyle factors that can play a role in causing depression. Some of these risk factors cannot be changed, such as your sex or your family history. Others such as diet and stress levels, are something that you have much more control over. Some of these include: Female Sex Hormones It has been widely documented that women suffer from major depression about twice as often as men. Because of the incidence of depressive disorders peaks during women's reproductive years, it is believed that hormonal risk factors may be to blame. Women are especially prone to depressive disorders during times when their hormones are in flux, such as around the time of their menstrual period, childbirth, and perimenopause. Hormone fluctuations caused by childbirth and thyroid conditions can also contribute to depression. Postpartum depression may occur after a woman has given birth, and is believed to result from the rapid hormonal changes that take place immediately after giving birth. In addition, a woman's depression risk declines after she goes through menopause. Circadian Rhythm Disturbances One type of depression, called seasonal affective disorder (officially known as major depressive disorder with seasonal pattern) is believed to be caused by a disturbance in the normal circadian rhythm of the body. Light entering the eye influences this rhythm, and, during the shorter days of winter, when people may spend limited time outdoors, this rhythm may become disrupted. People who reside in colder climates where there are short, dark days may be at the highest risk. In addition to disruptions in circadian rhythm, reduced sunlight can also lead to a drop in serotonin levels in the brain, which may influence mood. Seasonal changes can also alter melatonin levels in the body, which can disrupt sleep and contribute to mood changes. While you cannot control seasonal shifts, there are steps you can take to minimize the effect these changes have on your mental health. Physical Health The mind and the body are clearly linked. If you are experiencing a physical health problem you may discover changes in your mental health as well. Illness is related to depression in two ways. The stress of having a chronic illness may trigger an episode of major depression. In addition, certain illnesses, such as thyroid disorders, Addison's disease, and liver disease, can cause depression symptoms. Poor Nutrition A poor diet can contribute to depression in several ways. A variety of vitamin and mineral deficiencies are known to cause symptoms of depression. Some studies have found that diets either low in omega-3 fatty acids or with an imbalanced ratio of omega-6 to omega-3 are associated with increased rates of depression. In addition, diets high in sugar have been associated with depression. Stress Stressful life events, which overwhelm a person's ability to cope, can also be a cause of depression. Researchers suspect high levels of the hormone cortisol, which are secreted during periods of stress, may affect the neurotransmitter serotonin and contribute to depression. Grief and Loss Following the loss of a loved one, grieving individuals experience many of the same symptoms of depression. Trouble sleeping, poor appetite, and a loss of pleasure or interest in activities are a normal response to loss. The symptoms of grief are expected to subside over time. But when symptoms get worse, grief may turn into depression. Substance Use Drugs and alcohol can contribute to depressive disorders. But, even some prescription drugs have been linked to depression. Some drugs that have been found to be associated with depression include anticonvulsants, statins, stimulants, benzodiazepines, corticosteroids, and beta-blockers. It's important to review any medications that you've been prescribed and to speak with your physician if you are feeling depressed. How Substance Abuse Can Lead to Mood Disorders A Word From Verywell It is important to remember that no single cause of depression acts in isolation. Genetic factors may be a major risk factor for depression, but scientists also believe that genes and the environment interact to control exactly how these genes are expressed. No matter the cause, there are effective treatments available. Talk to your doctor if you have symptoms of depression in order to come up with a treatment plan that works for you. Was this page helpful? Thanks for your feedback! Everything feels more challenging when you're dealing with depression. Get our free guide when you sign up for our newsletter. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Lohoff FW. Overview of the genetics of major depressive disorder. Curr Psychiatry Rep. 2010;12(6):539-46. doi:10.1007/s11920-010-0150-6 Nutt DJ. Relationship of neurotransmitters to the symptoms of major depressive disorder. J Clin Psychiatry. 2008;69 Suppl E1:4-7. Albert PR. Why is depression more prevalent in women? J Psychiatry Neurosci. 2015;40(4):219-21. doi:10.1503/jpn.150205 Melrose S. Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Depress Res Treat. 2015;2015:178564. doi:10.1155/2015/178564 Abdel-motleb M. The neuropsychiatric aspect of Addison's disease: a case report. Innov Clin Neurosci. 2012;9(10):34-6. Rao TS, Asha MR, Ramesh BN, Rao KS. Understanding nutrition, depression and mental illnesses. Indian J Psychiatry. 2008;50(2):77-82. Aan het rot M, Mathew SJ, Charney DS. Neurobiological mechanisms in major depressive disorder. CMAJ. 2009;180(3):305-13. doi:10.1503/cmaj.080697 Utz RL, Caserta M, Lund D. Grief, depressive symptoms, and physical health among recently bereaved spouses. Gerontologist. 2012;52(4):460-71. doi:10.1093/geront/gnr110 Devido JJ, Weiss RD. Treatment of the depressed alcoholic patient. Curr Psychiatry Rep. 2012;14(6):610-8. doi:10.1007/s11920-012-0314-7 Rogers D, Pies R. General medical with depression drugs associated. Psychiatry (Edgmont). 2008;5(12):28-41. Additional Reading Aziz R, Steffens D. What Are the Causes of Late-Life Depression? Psychiatric Clinics of North America. 2013;36(4):497-516. Lohoff, FW. Overview of the genetics of major depressive disorder. Curr Psychiatry Rep. 2010; 12(6): 539-546. doi: 10.1007/s11920-010-0150-6. Lohoff FW. Overview of the Genetics of Major Depressive Disorder. Current Psychiatry Reports. 2010;12(6):539-546. Weissman, MM, Berry, OO, and Warner V. A 30-year study of 3 generations at high risk and low risk for depression. JAMA Psychiatry. 2016; 73(9): 970-977. doi: 10.1001/jamapsychiatry.2016.1586. Wigner P, Czarny P, Galecki P, Su K-P, Sliwinski T. The molecular aspects of oxidative & nitrosative stress and the tryptophan catabolites pathway (TRYCATs) as potential causes of depression. Psychiatry Research. September 2017.