Background: While clozapine is an effective treatment for refractory schizophrenia, its use is limited by haematological side effects. Treatment options that allow continued prescription of clozapine by tackling these side effects will greatly aid patients for whom this medication is all too often their only hope of recovery. Method: In this case report, we describe what we believe are two "firsts" in the clozapine literature: the use of granulocyte-colony stimulating factor on a "prophylactic" basis in an "intellectually disabled patient" receiving clozapine for refractory schizophrenia. Result: Treatment with granulocyte-colony stimulating factor prevented discontinuation of clozapine, enabling our intellectually disabled patient's recovery from a schizophrenic illness.