Our aim was to study anxiety and/or depression comorbidity and the influence of these comorbid conditions on disability for 3 clinical groups of pulmonary tuberculosis and chronic obstructive pulmonary disease (COPD). We also investigated the applicability of General Health Questionnaire 12 (GHQ12) for these clinical groups as a simple screening test for psychiatric comorbidity. A total of 157 male inpatients were included in the study: 42 with recently diagnosed (RDtb), 39 with defaulted (Dtb), 39 with multidrug resistant tuberculosis (MDRtb) and 38 with COPD. The presence of depression and anxiety was assessed by Composite International Diagnostic Interview (CIDI). Disability was evaluated by Brief Disability Questionnaire. The validity of GHQ12 for the study groups was examined in order to determine a functional cut-off point. Depression and/or anxiety comorbidity was 19% for RDtb, 21.6% for Dtb, 25.6% for MDRtb and 47.3% for COPD. Patients with psychiatric comorbidity had higher disability scores than the group without psychiatric comorbidity. For the tuberculosis group a 3/4 cut-off point of GHQ had 80.7% sensitivity and 87.1% specificity while a 5/6 cut-off point with 83.3% sensitivity and 80% specificity was applicable to the COPD group.