I adopted two dachshunds a while back. One I've had for nearly a year (Lenny), one I got around 4 months after the first (Dwight). I got Dwight because I thought Lenny was lonely. He seemed scared of everything and just all around depressed. He has improved since I got Dwight for him to play with, and they have both taken on characteristics of each other (Dwight took on more from Lenny than the other way around, even though Dwight is the dominant one). However, Lenny is still scared of everything but one of my roommates and my mom. I can only assume that whoever owned him before me treated him badly, but he seems to trust larger people (my roommate and my mom are both pretty big).
He's not lethargic in any way, just won't trust people, it seems. He won't look me in the eyes and has to always stay behind me. Despite all this, though, he always wants to be near me so I'm sure there's hope for him. Is there anything I can do that'll show him he doesn't have to be afraid of everything? He's around 2 years old now and hasn't shown much improvement since I got him despite being treated well.