You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

A crossover study of risperidone in children , adolescents and adults with mental retardation . Risperidone has shown safety and efficacy for aggressive and destructive behaviors in short-term studies . This longer-duration study includes a broad sample . Forty subjects , aged 8-56 years ( mean=22 ) , all with mental retardation and 36 with autism spectrum disorders participated in this 22-week crossover study , with 24 weeks of open maintenance thereafter . Of 40 subjects , 23 ( 57.5 % ) responded fully ( 50 % decrease in Aberrant Behavior Checklist-Community Irritability subscale score ) , while 35 subjects ( 87.5 % ) showed a 25 % decrease . Gender , mood disorder , and antiseizure medications did not alter response . Increased appetite and weight gain were common . Low dose risperidone was effective for aggressive behavior in persons with MR. More long-term studies are needed , incorporating weight control interventions .
{"Intervention": ["risperidone", "Risperidone"], "Outcome": ["aggressive behavior", "safety and efficacy", "effective", "Aberrant Behavior Checklist-Community Irritability subscale score", "Increased appetite and weight gain"], "Participant": ["Forty subjects , aged 8-56 years ( mean=22 ) , all with mental retardation and 36 with autism spectrum disorders participated", "children , adolescents and adults with mental retardation ."]}