Warning Signs of Depression

From Red Flags: Warning Signs of Depression

Changes In Activity or Energy Level
Decreased Energy
Fatigue
Lethargy
Diminished Activity
Insomnia or Hypersomnia
Loss of Interest in Pleasurable Activities
Social Withdrawal

Physical Changes
Unexplained Aches and Pains
Weight Loss or Gain
Decreased or Increased Appetite
Psychomotor Agitation or Retardation

Emotional Pain
Prolonged Sadness
Unexplained, Uncontrollable Crying
Feelings of Guilt
Feelings of Worthlessness
Loss of Self-Esteem
Despair
Hopelessness
Helplessness

Difficult Moods
Irritability
Anger
Worry/Anxiety
Pessimism
Indifference
Self-Critical

Changes in Thought Patterns
Inability to Concentrate
Indecision
Problems with Memory
Disorganized

Preoccupation with Death
Thoughts of Death
Suicidal Ideation
Feeling Dead or Detached

At the bottom of the article, there are links to a more detailed description of each category. All in all, a helpful article for both oneself and for identifying depression in family members.

Another helpful resource can be found in Recognize a Depressive Episode which emphasizes observation.