A novel psychoactive substance poses a new challenge in the management of paranoid schizophrenia.

Novel psychoactive substances (NPS), or 'legal highs' are becoming more commonly used as recreational substances in the UK. Their clinical effects are little known and vary considerably between substances. This case discusses a psychiatric inpatient who repeatedly used a stimulant NPS called 'el blanco' while on leave, precipitating relapses of his schizophrenia. The patient initially denied drug use, considering legal highs as different from drugs. The relationship between NPS use and mental state was eventually revealed on careful direct questioning. He recovered and was discharged following treatment with clozapine and education about NPS use. We suggest that specific questioning about NPS usage is added to routine psychiatric history taking and that patients using NPS should be educated about the substances' use.