It seems that I have come to an important realization: It is extremely hard for me to relax. Relaxation is a really unnatural state for me, because I usually strive for stimulating, exciting, interesting, fun activities, even if that’s simply thinking about a specific topic, or just letting my mind wander. Otherwise I feel understimulated, bored, and the longing to do something fun or productive, or at least something that distracts me from those and other negative feelings.
All of this makes me susceptible to addictive behaviour that makes me seek something that satisfies my desire for stimulation. Paradoxically, I have been most at peace when I had something really exciting and addictive that occupies my attention fully. It has become a kind of lifestyle for me to seek something that I can do fully and excessively, otherwise I wouldn’t even really feel alive.
The problem with that is that this way of living uses up lots of energy, and in the long run messes up neurochemistry (see Trying to understand neurotransmitter receptor regulation), because one is caught in a rapid endless loop of stimulation seeking behaviour, without any significant break. Heck, even my dreams often feel like just another way of generating extra stimulation while I’m asleep.
This is why it helps me to meditate, at least when I’m successful at meditating. Meditation disrupts the endless flow of thoughts and stimulation seeking behaviour. Similarly, when I’m in the forest 
and simply observe the nature around me, I’m in a different mode of mind – some kind of passive observer mode, an appreciative state 
. Those are the moments when some healing can happen, when my body and mind can get a short break from the ceaseless strom of stimulation, and stimulation seeking.
Perhaps I could be fixed thoroughly, if I lived in a buddhist monastery for a year or so. 
Not that I think that would actually be necessary. The deeper insight into my core problem might be enough to guide me to a path of solid healing.