Figure 3

Association of admission rates during a given 6-month calendar period with drug use in the preceding calendar period (n=1,406). The results are expressed as a change in the number of admission days per patient per year (means±95% CI); filled symbols indicate that the CI excludes zero. Interaction terms are expressed with colon notation. The number of patients taking each drug in at least one time period (whether alone or with another drug) is shown in parentheses (n); for interactions, this is the number of patients who took both drugs during the same time period, for at least one period. The effect sizes were derived from a regression analysis taking account of all other antipsychotic and antidepressant drugs in the analysis (see text), plus 6-month calendar period number (to account for overall trends over time), age, time since the first recorded diagnosis of schizophrenia (in years), and sex.