Many people believe that depression is caused by a chemical imbalance in the brain. However, that is not exactly true and is oversimplifying a very complex disease. The truth is no one knows exactly what causes depression. But there are a number of biological, psychological and environmental factors that can make a person more vulnerable to the disease. Research suggests that it may be the combination of several of these issues that, ultimately, lead to a clinical depression or major depressive disorder diagnosis. Here are the top eight factors that contribute to depression:
- Genetics: Having a family history of clinical depression may increase your risk of the disease. Studies have shown that people who have parents or siblings with clinical depression are up to three times more likely to suffer from the disease and as many as 40 percent of patients with major depressive disorder can trace it to a genetic link. For years, scientists have been trying to identify a “depression” gene or genes. For example British researchers recently isolated a gene (chromosome 3p25-26) found in more than 800 families with recurrent depression. To date, however, the research has not been consistent and scientists still haven’t been able to identify a specific gene that leads to depression in everyone. Some researchers say it may be multiple genes that, when combined, lead to a higher risk of clinical depression in certain families.
- Biology: Researchers have found differences in the brains of some people who have clinical depression. For example, the hippocampus, which is a small organ located in the brain’s medial temporal lobe appears to be smaller in people who have a history of depression versus those who do not. The hippocampus is part of the limbic system, which helps regulate emotions and plays a key role in memory—especially long-term memory. Having a smaller hippocampus means that you will have fewer serotonin receptors, which help regulate mood.
- Chemistry: There is strong evidence that one of the contributing factors to clinical depression is an imbalance in neurotransmitters, which are chemicals in the brain that communicate information. Neurotransmitters are responsible for relaying messages between nerve cells. For instance, they tell your heart to beat and your stomach to digest; they can also affect mood, sleep and concentration. The neurotransmitters that may contribute to depressive conditions include serotonin, which is influences mood, appetite, sleep and memory; norepinephrine, which regulates heart rate, blood pressure and your reaction to stress; and dopamine, which regulates the brain’s reward and pleasure centers and emotional responses.
- Hormones: Changes in your body’s hormone levels may also lead to depressive symptoms. Hormones help regulate bodily functions like growth and development, mood and metabolism. If you are suffering from chronic stress, for example, you may have elevated levels of cortisol, known as the “stress hormone.” This can result in reduced levels of serotonin and other neurotransmitters in the brain. Hormone imbalances related to pregnancy and thyroid disease may also lead to depression.
- Medication: Medications can have a lot of side effects, including nausea, fatigue, dry mouth and sun sensitivity. They can also affect your mood and lead to feelings of sadness, despair and discouragement. This is because they are altering your body’s chemistry. Your physician should inform you if a prescription could lead to depression or suicidal thoughts. Drugs that can cause depressive symptoms include, but are not limited to, corticosteroids, antidepressants, antimalarial drugs, acne medications, anticonvulsants, barbiturates, benzodiazepines, beta-blockers, opioids, statins and smoking cessation medications.
- Illness: There are a number of medical conditions that can manifest with depressive symptoms including heart disease, thyroid disease, multiple sclerosis, Alzheimer’s disease and Parkinson’s disease. There are also a number of chronic illnesses like arthritis and diabetes that can lead to depression. Patients who suffer from these conditions may become depressed because they are constantly in pain or frustrated by diet restrictions and limitations in physical activity.
- Environment: Many people with depression are triggered by an environmental factor, such as personal conflicts with family members or friends, abuse, moving, losing a job, getting divorced or the death of a loved one. Sometimes positive life events can lead to depression as well like having a child, starting a new job or getting married. Even a change in the weather can trigger depressive symptoms. While it’s normal in any of these circumstances to have feelings of sadness or hopelessness or nervousness or anxiety, usually those feelings will dissipate in a short amount of time. If those feelings persist for weeks or months and you are unable to perform daily activities or lose interest in favorite hobbies, you may be suffering from depression.
- Psychology: Some people are more prone to depression. For example, people who have low self-esteem, are overwhelmed by stressful situations, view the world or themselves in a negative way, have poor coping skills and struggle to process and express emotions. Likewise, people who suffer from other mental illnesses that make social interactions difficult are at higher risk of developing clinical depression.
Even though physicians don’t know the exact cause of depression, it is one of the most treatable mental illnesses. There is no reason to suffer in silence. If you are experiencing signs of depression, seek help from a medical professional right away.
TMS Neuro Institute is one of the earliest adopters in using transcranial magnetic stimulation to treat depression in Los Angeles. To schedule a consultation, call 888.823.4867 or book an appointment online here.