The symptoms of depression:

• Angry outbursts, irritability, or frustration, even with unimportant matters.
• Loss of interest or happiness in activities such as sex or hobbies.
• Sleep disturbances, including insomnia and sleeping too much.
• Tiredness and lack of energy for even the smallest activ...

People might experience brief periods of not feeling depressed, but this relief of symptoms lasts for two months or less. 

While the symptoms are not as severe as major depressive disorder, they are pervasive and long-lasting.

PDD symptoms include:

• Feelings...

• Lack of productivity
• Declining performance
• Feelings of hopelessness
• Increased irritability.