The implementation of Mental Health Nurse (MHN) prescribing in the UK remains disappointing. A much cited critique of MHNs prescribing is that it would be unsafe, as MHN would not have the appropriate knowledge of pharmacology to practise mental health prescribing. The knowledge of pharmacology of MHNs with the prescribing qualification has not been assessed in the UK. In addition, the views of MHNs with the prescribing qualification who have undertaken a psychopharmacology course have not been explored. The aims of this study are to measure the efficacy of a 10-day advanced training programme on psychopharmacology on the knowledge levels of MHNs with the prescribing qualification; and to explore the positive and negative experiences of individual participants of the training in psychopharmacology and how it supported their prescribing practice. A repeated measures design was used in which participants acted as their own controls. Participants were assessed 10 weeks before the training programme and again on day one of the training programme using a Multiple Choice Questionnaire. In addition, a series of focus groups were conducted to explore the helpful and unhelpful aspects of the course in sustaining the MHNs' prescribing practice. Following the training period there were significant increases in the MHNs' knowledge of psychopharmacology in comparison with the two base line means. Participants when interviewed 18 months after completing the training described the training as a helpful though they described it had not resulted in large increases in prescribing practice, citing systemic barriers to its implementation. Short and focussed training for MHNs who prescribe may increase their knowledge of psychopharmacology. The development of such programmes may well be part of the solution to support MHNs with the prescribing qualification to prescribe, supported by the views of the MHNs who participated in the focus groups. However, further work is required to remove organizational barriers. The data raise questions both about the current suitability of nurse prescribing preparation programmes in the UK and the suitability of NHS settings to support MHN to prescribe.