The causes of depression are not entirely known. The National Institutes of Health (NIH) notes that major life changes, childhood trauma or medical conditions could contribute to the onset and exacerbation of symptoms. Another possible cause is chemical factors, as they would directly impact how the brain functions. Some of the chemical sources of depression, like neurotransmitter and hormone imbalances, occur naturally but can be managed by the patient.
Neurotransmitter and Hormone Imbalance
Neurotransmitters like serotonin, norepinephrine and dopamine are involved in mood regulation. When the level of one of these neurotransmitters drops, it can lead to symptoms of depression. Antidepressants like selective serotonin reuptake inhibitors (SSRIs) target the receptors of the neurotransmitters and prevent their reuptake, resulting in more neurotransmitters being used by the brain and leading to an improvement in mood. Changes in hormone levels may also cause depression symptoms. During menopause, for example, when the levels of androgen, estrogen and progesterone are fluctuating, many women experience depression; the lower levels of the hormones interfere with mood regulation in the brain. When menopausal women were treated with estrogen, 80 percent had an improvement in mood, according to the "American Journal of Obstetrics and Gynecology" as reported by epigee.com, a women's health website.
Medications
Certain medications can also contribute to depression symptoms. The NIH states that sedatives and high blood pressure medications may be possible causes. However, the symptoms may be alleviated by changing the drug or dosage.
Alcohol and Illicit Drugs
Alcohol and illicit drugs such as psychotropics and opiates can also cause depression. Alcohol, for example, is a central nervous system depressant, and can negatively affect moods. Opiate withdrawal symptoms can also affect mood, and can also include anxiety, agitation and insomnia, according to the NIH.
Nutritional Deficits
Not having enough of a certain nutrient, like folate or omega-3 fatty acids, can also be a chemical source of depression. These nutrients are used by the brain to transmit the neurotransmitters involved with mood regulation. For example, omega-3 fatty acid supplements are an alternative method of treating depression, as they support nerve cell health.
