Psychiatric patients are being put in isolation rooms more often and for longer periods, despite pledges to ban the practice, according to current affairs show Nieuwsuur.

The number of instances in which patients were held in isolation rose 10% last year to 8,800, and the time spent there increased by 25%, figures from the health service inspectorate show.

The inspectorate did not investigate the reasons behind the increase but told Nieuwsuur the lack of staff is likely to be a factor. Frequent staff changes also mean staff are less familiar with patients, resulting in more decisions to isolate them.

In June 2016, the 15 regional mental health boards agreed to phase out the use of isolation rooms by 2020.

Patients who are aggressive or refuse to take their medication should no longer be isolated because it would only traumatise them more, they said. In addition, the practice contravenes the UN Convention on the Rights of People with Disabilities (CRPD).

The health board association said the figures did not paint a correct picture because of different interpretations of the term “isolation”  and improved registration. The inspectors, however, said that a rise was evident.

Junior health minister Vincent Karremans told Nieuwsuur the inspectorate must come up with more precise data “so we can have a proper discussion with the institutions”.

“The aim is to apply less force,” he said.