You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

Rural areas of the United States have been disproportionately impacted by the opioid epidemic, exacerbated by COVID-19-related economic upheavals. While polysubstance use is an important determinant of overdose risk, variability in polysubstance use as a result of numerous factors (e.g., access, preference) has yet to be described, particularly among rural persons with opioid use disorder (PWOUD). Survey data on past-month use of prescription and illicit opioids and 12 non-opioid psychoactive drug classes were analyzed from a national sample of rural (n=3872) and urban (n=8153) residents entering treatment for OUD from 2012 to 2019. Trend analyses for opioid and stimulant use were compared between rural and urban PWOUD. Latent class analyses assessed substance use trends through identified typologies of rural/urban PWOUD, which then underwent comparative analyses. By 2019, prescription opioid use remained greater in rural versus urban PWOUD, and methamphetamine use showed greater growth in rural, compared to urban areas. Latent class analyses identified variability in polysubstance use, with five identical subgroups in rural/urban PWOD: high polysubstance, polyprescription, prescription opioid-focused, prescription opioid-focused with polysubstance use, and illicit opioid-focused. Polyprescription was highest in rural areas, with illicit opioid-focused use highest in urban areas. Demographic characteristics, co-morbid conditions and healthcare coverage were all associated with between-group differences. There is significant variability in polysubstance use that may identify specific prevention and treatment needs for subpopulations of OUD patients: interventions focused on reducing opioid prescriptions, early engagement with mental health resources, wider distribution of naloxone, and screening/treatment plans that take into account the use of multiple substances.
["Prevention"]