Depression is a condition that is often overlooked and misdiagnosed. This is partly because the onset can be a bit more subtle than many other psychological disorders. Many times, it’s hard to spot the signs of depression because they appear slowly, over a period of time.

Many times someone will know they are not sick, but will not feel “right,” and wonder what the problem is. If they understood the symptoms of depression they would realize they had a serious problem that needed to be addressed. It’s important to recognize depression because it is a serious medical illness that won’t go away if only you would “snap out of it.” It’s a little more serious than just having a case of the blues.

According to the National Institute for Mental Health, in any given one year period, 9.5 percent of the population or approximately 20.9 million adults in the United States suffer from a depressive illness. The condition is often hereditary, running in families, and can be triggered by stressful incidents, such as relationship problems or financial difficulties as well as physiological conditions. Unfortunately, the symptoms of depression are very similar to those caused by other illnesses, which can prevent or delay much-needed medical treatment.

Some of the most commonly known symptoms of depression include feelings of emptiness or sadness, helplessness and hopelessness and feeling tired or fatigued. Other symptoms include difficulty concentrating on the task at hand, trouble making decisions, irritability or a lack of interest in former hobbies. Some of the symptoms can also be confusing or contradictory. For example, the disruption of sleep patterns can result in difficulty falling asleep, difficulty in sleeping through the entire night or waking up too early in the morning. During the depression, it is also common to experience unexplained changes in appetite that can result in either too much weight gain or too much weight loss.

One fact of depression that often surprises people is that symptoms of depression do not solely include mental issues, such as suicidal thoughts, but can also include physical symptoms such as chronic pain, headaches or digestive problems not due to another illness. As different as all these symptoms appear, they could all be a sign that you are depressed.

Because the condition will vary among individuals, not everyone will experience all of the symptoms of depression or the same severity of the symptoms. Depression does seem to run in families, according to many medical studies. Some differences exist, however. Women are twice as likely as men to experience depression, particularly around significant life changes such as pregnancy, the postpartum period and menopause.

Though most people believe that older people are more susceptible to experiencing the symptoms of depression as they age, this is not true. Depression is not a normal part of aging, but certain illnesses that are more common among senior citizens can lead to depression. Among these are heart disease, cancer, stroke, Parkinson’s disease and diabetes. As a result, the symptoms of depression among seniors can be overlooked and untreated. Some of the most common symptoms of depression include: Sadness and Anxiety, lack of energy and interest, physical illness, negative thinking, and fatigue and sleeplessness.

There is no one cause of depression. This illness tends to run in families. Researchers have theorized that it is a combination of a certain vulnerability due to hereditary factors and environmental factors (physical illness or stress). The combination of the two is thought to trigger an imbalance in the brain’s chemistry, which leads to symptoms such as feelings of hopelessness.

It is not clear whether the illness itself is caused by or merely a symptom resulting from certain neurotransmitters being out of balance. The three neurotransmitters involved are as follows: dopamine, serotonin, and norepinephrine. There are several factors that can contribute to a person feeling this way: hormones, heredity, stress and illness, medications and recent child birth.