['To investigate the pattern of associations between changes in unmet needs and treatment motivation in elderly patients with severe mental illness.', 'Observational longitudinal study in 70 patients treated by an assertive community treatment team for the elderly. Unmet needs and motivation for treatment were measured using the Camberwell assessment of needs for the elderly and the stages-of-change (SoC) scale, respectively, at baseline, after 9 and 18 months. SoC scores were dichotomized into two categories: motivated and unmotivated. Multinomial logistic regression analyses were conducted to determine whether changes in motivation were parallel to or preceded changes in unmet needs.', 'The number of patients who were not motivated for treatment decreased over time (at baseline 71.4 % was not motivated, at the second measurement 51.4 %, and at 18 months 31.4 % of the patients were not motivated for treatment). A decrease in unmet needs, both from 0-9 to 0-18 months was associated with remaining motivated or a change from unmotivated to becoming motivated during the same observational period (parallel associations). A decrease in unmet needs from 0 to 9 months was also associated with remaining motivated or a change from unmotivated to motivated during the 9-18 months follow-up (sequential associations).'] Does decrease in unmet needs contribute to improved motivation for treatment in elderly patients with severe mental illness?