Moodscope is very easy to use and is based on a rating scale developed by the American Psychological Association. The program shows you a set of 20 cards ranging from Anger, Irritation, Nervous, Attentive, Active, etc. For each card you self rate yourself on a scale from 1-4. Moodscope then tabulates your score and gives you a rating from 1-100. You can then plot this score over time and see how it fluctuates. Obviously you can follow your progress to see if methods of stress reduction for example, are helping with improving mood score. Moodscope also provides the feature of emailing your results to a trusted individual. This, under the premise that a trusted friend can provide the support to help lift you out of those dark moments. You can read more about Moodscope from this post by Alexandra Carmichael on the Quantified Self and the write up I did on Bytemarks.org.