Background The Netherlands has few financial barriers to access mental healthcare. However, in 2012, a sharp rise in co-payments was introduced. Aims We tested whether these increased co-payments coincided with less guideline-recommended continuous out-patient psychiatric care and more crisis interventions for patients with bipolar disorder. Method A retrospective longitudinal cohort study on a health insurance registry was performed to examine trends, and deviations from these trends, in the healthcare received by patients with bipolar disorder. Deviations of trends were tested by time-series analyses (autoregressive integrated moving average). Subsequently, the relationship between significant deviations of trends and rise in co-payments was examined. Outcome measures were the level of standard out-patient care (out-patient psychiatric care and/or medication), crisis psychiatric care and somatic care. Results The cohort comprised 3210 patients. During follow-up, the use of psychiatric care decreased and somatic care increased. The high rise in co-payments from 2012 onward coincided with decreases in standard out-patient care and increases in medication-only treatment, crisis psychiatric care and somatic care. Crisis intervention was highest when patients received only bipolar disorder medication. Patients receiving continuous standard out-patient care (62%) had less crisis intervention compared with the other patients. Conclusions Our data suggest that the rise of co-payments decreased guideline-recommended continuous out-patient psychiatric care among patients with bipolar disorder, and increased crisis psychiatric care.