Statistical time-series analyses of single case data allow a sophisticated person-centered evaluation of therapeutic effects. The possibilities and limitations of a new method of time series analysis are shown by the example of mood curves of neurotic depressive patients. The HTAKA model seems advantageous, because this procedure is less restrictive than other methods as regards the data basis. The cluster-analytical agglomeration of the single-case results indicates a sufficient response to antidepressants in about 40% of the patients who were treated with antidepressants in addition to psychotherapy.