A Slovenian study highlights the rapid weight increases among young psychiatric inpatients, raising concerns about medication effects and long-term health risks, especially with the use of antipsychotics like risperidone and quetiapine.
A study in Frontiers in Psychiatry has found that children and adolescents receiving inpatient psychiatric treatment can gain weight over a short hospital stay, with the rise appearing more pronounced among those given antipsychotic medicines. The retrospective analysis covered 776 patients under 18 treated between January 2022 and December 2024 at Slovenia’s main intensive psychiatric unit for young people. Among the 228 patients who had more than one body mass index-for-age standard deviation score, or BMI-SDS, recorded, the average change was small but positive, and the increase was significant in those exposed to antipsychotics.
The findings add to wider concerns about childhood obesity, which the US Centres for Disease Control and Prevention describes as affecting about one in five children and adolescents and carrying long-term health risks. Research cited by the authors also notes that obesity in young people is linked to later cardiovascular, endocrine and psychological problems. In the Slovenian cohort, the median hospital stay was three days, and longer admissions were associated with higher follow-up BMI-SDS after adjustment for baseline measurements.
Antipsychotic treatment was common in the sample: 455 of the 776 patients received one of these medicines during admission, while 321 did not. Of the antipsychotic-treated group, risperidone and quetiapine were the most frequently used drugs, followed by olanzapine and aripiprazole. Among patients with repeated BMI-SDS measurements, those given antipsychotics showed a statistically significant rise in BMI-SDS, while those without such treatment did not. The study also found that BMI-SDS changes differed across treatment groups, although olanzapine by itself was not significantly different from no antipsychotic treatment once multiple comparisons were taken into account.
That result does not mean olanzapine is weight-neutral. A 2025 systematic review and meta-analysis of second-generation antipsychotics in children and adolescents concluded that these medicines are associated with clinically meaningful weight gain and metabolic changes, reinforcing the need for close monitoring. In the Slovenian study, an exploratory analysis suggested that olanzapine exposure was linked to a higher chance of a BMI-SDS increase of at least 0.5, but the researchers said the data did not support a clear dose-response pattern. They stressed that BMI-SDS changes alone do not prove metabolic harm, because short inpatient weight changes can also reflect hydration, food intake, activity levels and measurement variability.
The authors say their results should be seen as a warning sign rather than evidence of causation. They argue that young psychiatric inpatients, especially those prescribed antipsychotics, should have structured weight and metabolic monitoring from the start of treatment and during follow-up. The study’s limitations include its retrospective design, the fact that only a minority of patients had repeat measurements, and the absence of data on diet, physical activity, puberty, blood markers and exact medication exposure. Even so, the authors say the findings support routine screening and highlight the need for prospective studies to track whether these early changes persist after discharge.
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