Here is the diagnostic criteria for Dysthymia, a lighter form of depression.
Depressed mood most of the day for more days than not, for at least 2 years, and the presence of two or more of the following symptoms that cause clinically significant impairment in social, work, or other important areas of functioning:
1. Poor appetite or overeating
2. Insomnia or sleeping too much
3. Low energy or fatigue
4. Low self esteem
5. Poor concentration or difficulty making decisions
6. Feeling hopelessness