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: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. 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:

Pregabalin abuse and dependence in Germany: results from a database query. PURPOSE: Pregabalin (PRG) is approved for the treatment of neuropathic pain, partial seizures and generalised anxiety disorder in many countries and currently under study for other indications. Supported by case reports and the results of a limited number of studies there is an ongoing debate on the potential of PRG to cause addictive behaviours. However, currently available evidence on this issue is sparse, and any definitive assessment of PRG's potential for abuse and dependence is not yet in sight. The aim of our study was to identify the number of cases of PRG abuse or dependence reported to the database of a German medical regulatory body and to obtain insights into further usage-specific parameters. METHODS: We conducted a query of the entire database of the German Federal Institute for Drugs and Medical Devices (BfArM) regarding reports of PRG abuse or dependence and analysed these cases on the basis of several parameters. RESULTS: A total of 55 reports of PRG abuse or dependence were identified (mean age 36 years, 64 % of reports involved males). The first reports were submitted to BfArM in 2008, and the reporting frequency has increased up to the present. Mean daily PRG dosage was 1424 mg. Current or previous polytoxicomania was present in 40 and 42 % of cases, respectively. Psychiatric diagnoses other than substance-related disorders were reported in 13 (24 %) cases. In about one-third of the patients withdrawal syndromes subsequent to discontinuation of PRG were reported. CONCLUSIONS: Cases of PRG abuse or dependence have been reported to the BfArM since 2008, with a marked increase of such reports in subsequent years. Male sex and a history of polytoxicomania may be possible risk factors for the development of addictive behaviours related to PRG.
{"Chemical": ["Pregabalin", "PRG"]}