I've decided to regard his cycles (and mine, because lord knows I have my own moods) like the weather. My mom's family is from North Dakota, where the weather is a daily drama. I have been there during clear spring days that ended in a blizzard, summer storms that delivered hail the size of grapefruits, and winter white-outs that leave you wondering if you're still on planet Earth. I think T., like a lot of kids in long-term foster care, grew up and grew accustomed to the emotional equivalent of life on those open plains. The fact that a day started out sunny and warm offered no guarantee that you wouldn't end up wind-whipped and disoriented that afternoon.
As a result, he's like someone who, having lived through a hurricane without any place to shelter, now prepares for disaster when he hears a few rain drops. How exhausting. Physiologically, the consequence of living that way is that he can only go so long before his system needs to power down. But life taught him that doing so is not safe, so he has trouble letting go. He can't relax himself; instead, he spirals into quasi-nihilistic episode of self-destructive behavior. It's as if he's telling himself "If I can't protect myself, I better just throw myself to the wolves."
The weather metaphor works for me too because it's as hard for me to control the factors that impact his mood as it is to control the weather. I can't prevent a call from his birth mom, stave off the intrusion of yet another social worker, deny a visit to see his relatives, or keep him from feeling let down when his best friend blows him off. Circumstances in his life are so complicated, he rarely goes more than a few weeks without a triggering incident. He is a deep, soulful person by nature and he absorbs these blows and processes them in a private place I can't always access. I try to protect him, but sometimes the elements catch up to us nevertheless. I'm making it a goal to teach him over time that the weather in our heads doesn't always have to reflect the weather outside. It is possible to build up internal resilience. You might open a door or window and let the rain come in, but when and for how long is up to you.