Real-world use of pharmacological treatments for incident bipolar disorder: A Finnish nationwide cohort study.

BACKGROUND

Pharmacotherapy remains crucial for treating bipolar disorder (BD), but knowledge on the treatments actually used by newly diagnosed patients in real-world settings is sparse.

METHODS

Individuals newly diagnosed with BD during 1996-2018, aged 15-65 years, were identified from national Finnish registers. The patients' use of different drug classes (mood stabilizers, antipsychotics and antidepressants) or combinations of these drug classes were followed from initial pharmacotherapy (first line) after BD diagnosis until the fifth line of treatment or until the two-year follow-up time ended. Clinical and sociodemographic factors associated with antidepressants-only as the first treatment line were assessed with logistic regression.

RESULTS

82.6 % of all patients used BD medication during the follow-up. 33.9 % had antidepressants-only as the first, 22.9 % as the second and 19.7 % as the third treatment line. Use of combinations of mood stabilizers, antipsychotics and antidepressants increased by successive treatment lines. Factors associated with antidepressants-only as the first treatment line included older age (>45 years aOR 2.20, 95% CI: 2.01-2.40, 25-45 years: 1.55, 1.42-1.68, compared with those aged <25), diabetes (1.35, 1.17-1.55) and female sex (1.29, 1.21-1.37). BD diagnosis registered in 2016-2018 (0.48, 0.42-0.55) and substance abuse (0.77, 0.71-0.83) were associated with decreased odds.

LIMITATIONS

Due to the register-based nature of this study, not all potentially important clinical factors influencing medication use could be controlled for.

CONCLUSIONS

A large proportion of patients with bipolar disorder are not treated according to treatment guidelines, as use of antidepressants alone is common. Reasons for not following evidence-based recommendations need to be further researched.