Moodtracker works to show me if I have a pattern going on long enough to be concerned, whether up or down, plus it tracks my anxiety levels in regards to my mood levels. That can show me moving towards mixed because high anxiety almost always travels alongside. Also, since I am in perimenopause it helps track my periods. That's how I was able to tell that my last very depressed episode also coincided with three months of no period. I can see how my hormones interact with my neurotransmitters.
A plus is the journaling part, I use it as a diary of sorts so I can also see what life events were going on during any given timeframe.
I've been using moodtracker.com since 2009.