LOSS OF FOLLOW-UP INFORMATION REGARDING THE ADJUSTMENT OF PEOPLE WHO HAVE RECEIVED MENTAL HEALTH SERVICES HAS BEEN OF CONCERN BECAUSE A LOW RESPONSE RATE MAY INDICATE THAT PATIENTS ARE ADUSTING POORLY. THUS, THE TREATMENT EFFECTIVENESS OF PROGRAMS HAVING LOW FOLLOW-UP RESPONSE RATES WOULD BE INACCURATE. THE PRESENT STUDY COMPARES THE FOLLOW-UP ADJUSTMENT OF PATIENTS ON WHOM INFORMATION WAS OBTAINED BY MAIL WITH THE ADJUSTMENT OF MAIL NONRESPONDENTS WHO WERE LATER INTERVIEWED BY PHONE. DATA COLLECTORS WHO MADE THE CALLS HAD BEEN TRAINED TO FOLLOW THE SAME INTERVIEW FORMAT AS THE MAILED QUESTIONNAIRES. ADJUSTMENT AREAS COVERED WERE VIGOR, ALIENATION, AND CONFIDENCE IN SKILLS. THERE WERE 507 PATIENTS IN THE COOPERATIVE GROUP AND 190 IN THE RELUCTANT GROUP CONTACTED BY PHONE. THE FINDINGS INDICATE THAT THE POSTHOSPITAL ADJUSTMENT OF PATIENTS WAS NOT A SIGNIFICANT FACTOR IN DETERMINING WHETHER MAILED FOLLOW-UP QUESTIONNAIRES WERE RETURNED. RATHER, LOW RESPONSE RATES WERE PRIMARILY A FUNCTION OF DATA COLLECTOR STYLE AND MOTIVATION LEVEL OF THOSE RECEIVING MAILED QUESTIONNAIRES. TABULAR DATA AND REFERENCES ARE INCLUDED. (AUTHOR ABSTRACT MODIFIED -- MRK)