The brain is unique—it is the only organ whose function we consciously experience because the brain is the organ of the mind.
Feeling down, sad, or upset is normal. However, it can be concerning to feel that way for several days or weeks.
Physical Symptoms
Physical symptoms and behavioral changes caused by depression include:- Decreased energy
- Chronic fatigue, or feeling sluggish
- Frequently difficulty concentrating
- Making decisions
- Recalling pain, aches, cramps
- Gastrointestinal problems without any clear cause
- Changes in appetite or weight
- Difficulty sleeping, waking early, or oversleeping
Emotional Symptoms
Emotional symptoms of depression include:- Loss of interest or no longer finding pleasure in activities or hobbies
- Persistent feelings of sadness, anxiety, or emptiness
- Feeling hopeless, helpless, worthlessness, or pessimistic
- Feeling anger, irritability, or a restlessness feeling of guilty
- Thoughts of death, suicide or suicide attempts
Citation
P Bech, et al. The sensitivity and specificity of the Major Depression Inventory, using the Present State Examination as the index of diagnostic validity. 66 J Affect Disord 159-164. 2001.
LR Olsen, et al. The internal and external validity of the Major Depression Inventory in measuring the severity of depressive states. 33 Psychological Medicine 351-356. 2003.