To asses competence to consent to treatment in involuntary committed patients (ICP) for a mental disorder, as compared to matched acute voluntary hospitalized patients (VHP). To evaluate the effect of psychopathology severity and cognitive dysfunction on decisional capacity.

Cases were recruited among ICP at the Umberto I Hospital, ‘Sapienza’ University of Rome; controls were age- and sex-matched VHP, in the same ward and time period. Subjects were diagnosed according to DSM-IV-TR criteria and further evaluated through a) MacArthur Competence Assessment Tool for Treatment (MacCAT-T) b) Brief Psychiatric Rating Scale-24 (BPRS) c) Raven's Colored Progressive Matrices (CPM) d) Mini Mental State Examination (MMSE).

Eighteen cases were enrolled (67% women), mean age was 25.1 ± 2.8 years. There were no differences between groups in: diagnostic distribution (40% schizophrenic spectrum disorders, 40% mood disorders, 20% other diagnosis), disease duration, MMSE. ICP had higher BPRS total scores (mean difference ± S.D.= 10.3 ± 19.4; [95% C.I.= 0.6 ÷ -20.0]), and performed worse than VHP in MacCAT-T comprehension (-1.0 ± 1.3; [95% C.I.= -1.6 ÷ -0.3]), appreciation (-1,7 ± 2.0; [95% C.I.= -3.0 ÷ -0.7]), reasoning (-2.1 ± 2.9; [95% C.I.= -3.6 ÷ -0.7]) and expression of a choice (-0.8 ± 1.0 [95% C.I.= -1.3 ÷ -0.3]). Competence to give informed consent was associated with psychopathological dimensions but not with MMSE and CPM scores, in the sample overall.

Competence to consent to treatment was reduced in ICP compared to VHP. Involuntary commitment was not necessarily associated with incapability of making treatment decisions.