“Let’s begin with a basic definition:”
Researchers have found that depression is not an imaginary illness, there is a part of the brain called the hippocampus which is associated with memory and emotion, this can shrink by up to 17% when someone develops depression, so depression is very real.
Hippocampal volume in early onset depression. BMC Med 2004 Jan 29;2. Epub 2004 Jan 29. Frank P MacMaster, Vivek Kusumakar.
Clinical depression is usually accompanied by several of these identifiable signs that persist for at least two weeks:
Persistent low mood or sadness
Fatigue or low energy levels
Feelings of dejection, despondency, apathy, and hopelessness
Lack of energy
Trouble sleeping, or sleeping a lot more than usual
Significant weight loss or weight gain
Loss of interest in work, recreational activities, interests
Loss of interest in food
Neglect of personal hygiene
Cognitive abilities are slowed or difficult
Anger
Inability to function in normal tasks
Suicidal thoughts
It is really important to get this checked out by a doctor to rule out other medical conditions that can mimic depression, for example thyroid and hormonal issues can cause very similar effects as depression.