In 2011 I wrote about my experiences of depression, how they interacted with changes in the volume and intensity of my cycling, and introduced some academic literature on exercise and mental health. I concluded that although cycling can play a role in moderating negative mood, and possibly even treating depressive illnesses, it can also contribute to depressive symptoms. A recent paper on exercise and mental health provides a detailed overview of the literature in this area (many thanks to Simon Lamb for the tip).
I have had my ups and down over the last few years, but, partly due to a change in my work role, and some growing up from my children, I have maintained a fairly positive outlook. Another thing that has changed is the amount of time I have spent cycling. Throughout 2012 I rode more often and tackled some longer rides, but managed to talk myself out of entering a number of brevets and sportives, and more irritatingly, entered two 200km brevets that I failed to start. Fortunately, I convinced myself that I was capable of completing the long on-road version of the Mills Hills Sportive, which was a breakthrough in my conversion from self-sabotage to gung-ho risk-taker (a brief ride report for Mills Hills Sportive)!
I am currently riding about 120km per week, three times my 2011 average. All of a sudden, having completed three challenging longer rides (including my second 400km, only 10 years after the first), I can see myself completing Super Randonneur series in 2014 and 2015, and even Paris Brest Paris…
The causality here is tangled. Am I riding more, and more confidently, because I am happier, or vice-versa? I think this is the wrong question…
Almost all my riding is solo, but I have had some fun in the hills with some lovely people: thanks Emma and Tiffany, and the riders and organisers of the events I have ridden. My partner in crime @accidentobizaro has been incredibly supportive and encouraging, and when we get the chance, our velodates are always worth waiting for, whether on the track or in the Pennine hills we call home.
cyclismespandelles 
Depression brought me to a standstill in 1998. After a brief dabble with Prozac I gave more importance to allocating cycling time. The next few years saw me achieve SR status and qualify for PBP.
I never entered PBP as a 600k was far enough for me. It gave me the confidence and knowledge to get on a bike and go anywhere I wanted.
Now commuting and occasional long runs keep those dark demons away. I know its what makes me smile and know I must make time for it.
Glad you have found your balance again! I am exploring my limits at the moment, very carefully…
I was on citalopram for a while: useful but wasn’t a long term solution for me.
I found that cycling – mainly with a view to ticking off cols in France – gave me a massive lift in the last five years. But I have suffered with overtraining and a kind of lifestyle perfectionism (trying to live like a pro, basically) that started to make me very miserable and when compounded with niggling injury last year really brought back the clouds….I’m cycling again now and loving it. I’ve had to realise it is only one aspect of a better life.
It is so easy to be drawn into the pseudo-pro lifestyle: I seem to go wrong when I compare with others!