Comorbidity between drug misuse and mental disorders affects negatively in the prognosis of psychiatric illness, so it’s important to guarantee drug abstinence during hospitalization.

The Hospital of Zamudio contains short and medium stay units. Patients are referred to medium stay units when disorders are more serious or the symptoms are resistant to treatment.

In February 2003, a multidisciplinary group was formed to evaluate the situation of drug use in a psychiatric hospital and a drug screening protocol was then created.

We evaluate if the enforcement of the protocol, has decreased drug use during hospitalization.

It’s compared, retrospectively, drug use (positive results in urine samples) since the screening drug protocol was enforced (2003) to 2007. Urine samples are collected when there’s a past misuse history, consumption suspicion, randomly and every time the patient leave for home. It’s also compared the differences between short and medium stay units.

It’s proved that drug use decreases during hospitalization since the new protocol came into force in a medium stay unit. This drug protocol is not useful in a short stay unit.

The introduction and completion of this protocol provokes a high reduction of drug use in a medium stay unit. This design seems not to be adequate to short stay units. Probably, collecting urine samples when patients came into a short unit gives false positive results because these patients don’t come from other hospitalization units as in the case of medium stay unit.