Could you tell me what are signs that a person is always depressed?

Symptoms: Low mood, irritability, loss of interest in activities, low energy, changes in sleep and appetite, impaired concentration and memory, feeling helpless, worthless, in addition to suicidal thoughts.

More Depressive sxs.: Dr heller provided an excellent answer. I thought i would add in some additional possible symptoms. Lack of joy is a hallmark symptom of depression. Motivation levels may be low & could effect work performance. Sex drive may either be decreased or in some cases where sex is a distraction from pain, it could be increased. Self esteem drops. Early morning awakening can be a classic form of insomnia.