## 3 Collection of the Corpus
### Statistics of the Collected Corpus
Regarding diseases, the most frequent ICD-10 top level categories are \"X--Diseases of the respiratory system\" (1122 reviews); \"I--Certain infectious and parasitic diseases\" (300 reviews); \"V--Mental and behavioural disorders\" (170 reviews); and \"XIX--Injury, poisoning and certain other consequences of external causes\" (82 reviews). The top five low-level codes from ICD-10 by the number of reviews are presented in Figure 3.  
Analyzing the consumers' motivation to acquire and use drugs (\"sourceInfoDrug\" attribute) showed that review authors mainly mention using drugs based on professional recommendations. Of the reviews, 989 mention doctors' prescriptions, 262 refer to pharmaceutical specialists' recommendations and 252 refer to doctors' recommendations. Some reviews report using drugs recommended by relatives (207 reviews), or chosen on the basis of advertisement (97) or the Internet (15). Figure 2: The percentages of different sources of information for the 20 most popular (in the collected corpus) drugs. The number in a cell means the ratio of reviews with co-occurring mentions of a drug and a particular source to the total number of reviews with this drug. If several different sources are mentioned in a review, it is counted as the “mixed” source. The heatmap presented on Figure 2 shows the percentages of different sources of recommendation for a few popular drugs. The sources were manually merged into five groups by the annotators. It could be seen that most recommendations are coming from professionals. For example, Isoprinosine (used in 65.85% cases by medical prescription), Aflubin (44.09%), Anaferon (47.30%) and others. However, for such drugs as Immunal (11.9%) or Valeriana (9.18%), the rate of usage on the advice of patients' acquaintances is close to doctors' recommendations or higher. Of all the drugs, Amizon and Kagocel are most frequently (12.73% and 11.27%, respectively) mentioned by the users as chosen on the basis of information from mass media (advertisement, internet and others). The distribution of the tonality (positive or negative) for the sources of information is presented in Figure 4. A source is marked as \"positive\" in a review if a positive dynamic is reported after the use of the drug (i.e., the review includes a BNE-pos attribute). \"Negative\" tonality is marked if a negative dynamic or deterioration in health has taken place or the drug has had no effect (i.e., Worse, ADE-Neg or NegatedADE mentions appear). Reviews that report both positive and negative dynamics are considered neutral and do not count towards the distribution. Figure 4: Distribution of tonality for the different sources. A number in brackets shows the number of reviews that mention a certain source of information, including reviews without reported effects or neutral reviews (with both good and bad effects). Figure 3: Top five low-level disease categories from ICD-10 by the number of reviews in our corpus. J00-J06—Acute upper respiratory infections, J11—Influenza with other respiratory manifestations, virus not identified, B00—Hepesviral [herpes simplex] infections, F51.0— Nonorganic insomnia and T78.4—Allergy, unspecified. The diagram in Figure 4 shows that drugs recommended by doctors or pharmacists are mentioned more often as having a positive effect, while using drugs based on an advertisement often leads to deterioration in health. Diagrams in Figure 5 show the percentages of reviews where popular drugs were mentioned along with labeled effects. The following drugs have the highest occurrences of ADR in reviews: immunodulator \"Isporinosine\" (48.8% of reviews with this drug contain ADR mentions), antiviral \"Amixin\" (40.0%), tranquilizer \"Aphobazolum\" (37.7%), antiviral \"Amizon\" (36.4%) and antiviral \"Rimantadine\" (36.3%). For some drugs, users mention negative dynamics of the disease after the start or some period of their usage (ADE-Neg).