BackgroundReadmissions in psychiatric inpatient care may reflect problems in the provision of care, but the underlying factors are not well known. We examined the associations of patient characteristics (sociodemographic factors, diagnoses), treatment (duration, previous episodes, neuromodulation) and ward overload with psychiatric inpatient readmissions and multiple readmissions in Finland.MethodsWe used a routinely collected data pool from one hospital district and followed all 2052 hospitalizations that started in 2018. The outcomes were readmission within 30 days and one year, and among those with readmission, the number of readmissions.ResultsOf the patients, 11% had readmission within 30 days and 33% had readmission within one year. Women, those with previous hospitalizations, those with an ICD-10 diagnosis from the ‘behavioural syndromes associated with physiological disturbances and physical factors / disorders of adult personality and behaviour’ group, those with a diagnosis from the ‘neurotic, stress-related and somatoform disorders’ group, those with psychotic disorders, and those who received neuromodulation treatment were more likely to have readmissions. Having a diagnosis of ‘disorders of psychological development’ or ‘behavioural and emotional disorders with onset usually occurring in childhood and adolescence’ was associated with a lower likelihood of readmission. The duration of treatment and ward overload during the index period were not associated with readmission.ConclusionsThe findings of this study suggest possible risk factors for readmission and can be used to plan psychiatric care. To some degree, the risk factors varied between different readmission types. It is important to examine whether there are unmet treatment needs in psychiatric inpatient care for children and adolescents.