BACKGROUND: Measures have not taken account of the relative importance patients place on various outcomes. AIMS: To construct and evaluate a multidimensional, preference-weighted mental health index. METHOD: Each of over 1200 patients identified the relative importance of improvement in six domains: social life, energy, work, symptoms, confusion and side-effects. A mental health index was created in which measures of well-being in these six domains were weighted for their personal importance. RESULTS: The strongest preference was placed on reducing confusion and the least on reducing side-effects. There was no significant difference between the unweighted and preference-weighted mental health status measures and they had similar correlations with global health status measures. Patients with greater preference for functional activities such as work had less preference for medical model goals such as reducing symptoms and had less symptoms. CONCLUSIONS: A preference-weighted mental health index demonstrated no advantage over an unweighted index.