ISRCTN68824876.

Trial name or title	Amisulpiride augmentation in clozapine‐unresponsive schizophrenia.
Methods	Allocation: randomised. Blindness: double‐blind. Duration: 12 months.
Participants	Diagnosis: schizophrenia. Target sample size: 230. History: persistent symptom severity despite adequate trial of clozapine, treatment for > 12 weeks (400 mg or more of clozapine/day), total score of 80 or greater on PANSS, CGI score of 4 or greater, SOFAS score of 40 or less.  Age: 18‐65 years.
Interventions	Combination therapy: amisulpiride + clozapine. Monotherapy: placebo + clozapine.
Outcomes	Clinical response: not clinical improved (20% reduction in total PANSS score). Mental state: PANSS negative symptom sub‐scale score, CDSS.  Functioning: SOFAS.  Service use: Service engagement scale. Adverse effects: Antipsychotic side effect measures. Quality of life: Euroqol EQ‐5D. Economic: resource use data questionnaire.
Starting date	September 2010
Contact information	Prof. Thomas  Barnes (t.r.barnes@imperial.ac.uk) Centre for Mental Health  Imperial College  Charing Cross Campus  St Dunstan's Road London W6 8RP
Notes	ISRCTN trial registration ID: ISRCTN68824876 Sponsor: Imperial College London (UK)