Depression: Causes, Symptoms & Treatments

By: Joseph M. Carver, Ph.D.



Depression is perhaps the most common of all mental health problems, currently felt to affect one in every four adults to some degree. Depression is a problem with mood/feeling in which the mood is described as sad, feeling down in the dumps, being blue, or feeling low. While the depressed mood is present, evidence is also present which reflects the neurochemical or "brain chemistry" aspects of depression with the depressed individual experiencing poor concentration/attention, loss of energy, accelerated thought/worry, sleep/appetite disturbance, and other physical manifestations. When this diagnosis is present, the individual will exhibit at least five of the following symptoms during the depressive periods:

- Depressed mood, most of the day or every day
- Markedly diminished interest in all or almost all activities
- Significant weight loss or gain or appetite disturbance
Depression Questionnaire
1. Over the past two weeks have you had persistent thoughts of death, dying, or suicide?

2. Over the past two weeks have you had a plan to end your life?

Take Depression Questionnaire
- Insomnia or excessive sleeping
- Psychomotor agitation or retardation (restlessness)
- Low energy level or chronic tiredness
- Feelings of inadequacy, loss of self-esteem, and/or self-deprecation
- Decreased attention, concentration, or ability to think clearly
- Recurrent thoughts of death or suicide, an expressed desire to be dead

Causes of Depression:

Sudden Severe Loss: In this situation, the individual has experienced a sudden, perhaps surprising severe loss. This loss may be the death of a loved one, loss of a job, loss of friendship, or other grief process. In this type of depression, the patient can clearly identify what is creating the depressed mood.

Long-term High Stress Level:
In this situation, the patient is depressed but can't quite put their finger on the cause, the "I'm depressed but I don't know why" condition. Imagine running a video tape of your life, reviewing the past 18 months. Look at the stress you've been under, the amount of responsibility, the number of pressures, and the number of hassles. In actual clinical practice, this cause of depression is seen more often than sudden loss. This type of depression creeps up on you. When this type of depression is experienced, the patient offers comments such as: "I don't know what's wrong!" "I don't know how I feel." "My feelings are numb."

Brain Chemistry and Depression:

The human brain operates, much like your automobile, on fluids called neurotransmitters. Just as your automobile has brake fluid, antifreeze, transmission fluid, and oil - your brain runs on these neurotransmitters. Some give us energy, like those related to adrenalin, some control body movements ("dopamine" as an example), and some control mood.

The brain neurotransmitter often associated with depression is called

. Serotonin is the brain's "oil", a rather slow-acting neurotransmitter that is associated with sleep, appetite, energy, alertness, and mood - just to name a few. Using the automobile as an example, if we drive our car to California at a speed of 120 mile per hour, running the engine hot for a long time, it would obviously use more oil. As long as we provided gas, however, it would continue to run. Now suppose in our trip that for every two quarts of oil we burn, we only replace one quart. By the time we reached California we'd be several quarts low and our engine would be obviously overworked and overheated.

During long-term high stress, the brain burns its' oil, serotonin, at a higher rate. The bottomline in depression and stress:

The brain burns up more serotonin than it can replace!
In the end result, after many months of severe stress, the brain is using serotonin faster than it can create/replace it. Your neurochemical level of serotonin drops and you become depressed.