The NYT website has a prominently featured piece titled “In Sleepless Nights, a Hope for Treating Depression”… I read it with interest as I’ve from time to time had brutal, grinding insomnia (as have many other writers I know).  Extended periods of insomnia do not in my experience alleviate depression in any way.  On the other hand–and this is not insomnia–there are those nights (rather, mornings) when dawn breaks and you’ve been writing nonstop all night and your exhaustion becomes a kind of euphoria.  Writing as a profession or lifestyle can be disruptive to circadian rhythms because of those nights–they can fuck up your sleep schedule for a week.  (This just happened to me in the last few days, totally disoriented my mind and body in relation to time of day, and may or may not have contributed to a minor car accident.)  But those nights are actually one of my favorite parts of being a writer–those nights are when you get the pure joy of creative endeavor unadulterated by the logistical headaches of publishing and promoting and etc etc etc.