In bipolar disorder, hospital treatment is generally required in acute manic episodes, due to lack of compliance and adherence to treatment, and in episodes with marked depressive symptoms, especially suicidal ideation. Analyzing patterns of hospital admission rates is important in order to estimate treatment outcomes in both the acute and remitting phases of the disease. The aim of this study was to analyze secular trends in admissions and re-admissions for bipolar disorder in Sweden.

For bipolar disorder and its subdiagnoses, the number of admissions, length of stay and days in hospital during 1997-2005 was calculated. Readmission rates over five years were calculated for patients discharged for the first and the second time during 2000.

The number of admissions for patients with bipolar disorder in Sweden increased from around 3,500 to more than 4,000, partly explained by increasing rates of first admissions. Three fourths were readmissions. Hospital days increased, since the length of stay was not reduced. Manic episodes represented half the hospitalizations, depressive a quarter, and mixed ten percent. Patients with their second admission had 1.9 readmissions during five years, compared to 1.2 for patients with their first admission in 2000.

Physicians should consider early and effective treatment with long term outcomes in mind. The progressive course is clearly shown by the increasing rates of readmissions after the second admission compared to the first. The increasing number of first admissions is an indication that more patients have received a bipolar disorder diagnosis.