Most people with depression do not often present to their Family Doctor and say, "Doctor I have depression". They often present with tiredness, feeling fatigued, poor sleep, unmotivated to go to work, poor concentration, and problems in their personal relationship. Other symptoms include hopelessness, worthlessness, feeling flat or on edge, insomnia, broken sleep particularly early morning wakening, poor appetite, poor libido and even thoughts of self harm.
I, as a Family Doctor, on a practical level define depression simply as persistent flat mood that is severe enough to affect your work performance and relationship. Let's face it, most of us feels flat or sad from time to time. This is quite "normal". However, when it is intense and protracted enough to affect your function, ie affecting your relationship and work performance, then we say that there is a problem and we need to manage it.
So next time you feel persistently flat, stress or anxious, then consider speaking to your Family Doctor about it early. The earlier we can intervene, the better the prognosis. Intervention, does not necessarily have to be medications as specific counselling like CBT(Cognitive Behavioural Therapy) and ACT(Acceptance Committed Therapy) maybe extremely effective in managing depression.