Some patients given growth-promoting therapy for GH deficiency in childhood will remain GH deficient in their adult lives and hence could benefit from continued GH replacement therapy. This longitudinal study sought to assess whether quality of life declines after GH discontinuation in late adolescence, and whether differences can be discerned in quality of life in patients whose GH deficiency persists into adulthood and those whose GH secretory capacity falls within normal ranges. Forty patients, aged 16-21 yr at baseline, were assessed over a 2-yr period commencing with discontinuation of GH therapy. Twenty-one patients were assigned to a GH deficiency group, and 19 were assigned to a GH-sufficient group. Quality of life assessments were made using the Nottingham Health Profile, Psychological General Well-Being Index, and Mood Adjective Check List Measures. Visual analog assessment of personality and affect and cognitive function tests were performed. The Mood Adjective Check List and visual analog assessments identified between-group and temporal changes in a limited number of the various personality domains assessed. The Psychological General Well-Being Index assessment indicated greater baseline impairment in the GH deficiency group than in the GH-sufficient group in overall score and in the domains of depression and general health. There was also a between-group difference in anxiety score at the 2-yr assessment, with the GH deficiency group having greater anxiety. Measurement of cognitive factors failed to reveal differences between groups. These results indicate that the discontinuation of GH therapy in late adolescence does not risk an immediate decline in the perceived quality of life detectable with the Nottingham Health Profile and Psychological General Well-Being Index measures. However, differences detected with the Mood Adjective Check List and visual analog assessments hint at clinically significant changes in the life experiences of adolescents discontinued from GH for which traditional measures may lack sensitivity.