Examined the differences between older research non-responders and older completers and between older research non-responders and younger ones. As part of a large cooperative Veterans Administration study, a sample of 619 older non-responders were compared to 964 older completers and also to 4,73 1 younger non-responders on basic demographic and treatment factors, as well as on self-rated adjustment dimensions. Among other factors, results show that older non-responders tend to be substance abusers, to be "loners," but have equal or better adjustment ratings than older completers; and among other variables, older non-responders tend to be "first timers" in psychiatric hospitals, to have greater treatment expectations, and to rate themselves with better adjustment in many areas relative to younger nonresponders.