Background: Alcohol, drugs and tobacco consumption is the most common type of risky behaviors among adolescents. Determinating the speciffic patterns of these behaviors in a particular environment would provide guidelines for creating speciffic prevention programs. Aim: To determine the prevalence, circumstances and risky factors for alcohol, drugs and tobacco consumption among high school students in Split-Dalmatia County (SDC), differences between schools (vocational vs. gymnasiums and private schools) and differences depending on the place of school attendance (Split and surroundings, rural parts, islands), as well as changes in alcohol consumption during the COVID-19 pandemic lockdown. We also wanted to determine the frequency and changes in hospitalizations due to acute alcohol intoxications (AAI) among children aged 0-18 in the period from 2008 to 2015 and compare them with the results from 2016 to 2021, as well as changes in circumstances that led to intoxication. Methods: An anonymous questionnaire survey was distributed online to final grade high school students of all schools in SDC (N = 1030). Students were able to complete the questionnaire survey in a period from June to July and from October to the end of December 2020. The data of children aged 0 to 18 years who were hospitalized for AAI at Department of Pediatrics, University Hospital of Split in a period from January 1, 2008 to December 31, 2021 (N = 272 from 2008 to 2015 and N = 71 from 2016 to 2021) were collected retrospectively from hospital medical records. Results: The prevalence of smoking among students in SDC is 37.28 %, drugs consumption 24.27 %, and drinking 84.66 %. Students attending vocational schools smoke more often than students in gymnasiums and private schools (P < 0.001), while there is no difference in alcohol (P = 0.751) and drugs consumption (P = 0.192) between students depending on the school type. Boys consume drugs more often (P = 0.013) than girls, while there is no difference in alcohol (P = 0.328) and tobacco (P = 0.85) consumption depending on the gender. Smoking is most common among students from the rural parts of SDC (P = 0.037), alcohol consumption on islands (P = 0.007), and drugs in Split and the surrounding area (P = 0.029). Students most frequently drink in nightclubs and coffee bars (54.36 %), with friends (92.89 %), “to feel better” (34.86 %), where they often drink mixed drinks (39.33 %). Students most often buy alcoholic beverages without any problem (85.33 %) and 69.03 % had been drunk in lifetime. While the greater amount of pocket money, employment, frequency of going out, depression, male gender, higher level of maternal education and having divorced parents increase the risk of participating in risky behaviors, religiosity, higher frequency of religion practicing, sports participation, and higher school performance reduce it. During the COVID-19 pandemic lockdown, there was a significant decrease in alcohol consumption among high school students in SDC (P < 0.001), especially with friends (P < 0.001), while the frequency of drinking with family members (P < 0.001), drinking alone (P < 0.001) and in different social context (P = 0.002) increased. Students were most often drinking out of boredom (39.05 %) during the lockdown. There was a decrease in frequency of drinking during the lockdown among 53.98 % of students, while 15.63 % of them increased it (P < 0.001). The decrease in alcohol consumption was more signifficant among students in gymnasiums and private schools than among students from vocational schools (P = 0.002), as well as among students on islands (P = 0.050). Boys were drinking more often than girls (P < 0.001) during the lockdown period. A significant decrease in AAI among children aged 0-18 years was also recorded in 2020 (pandemic period) compared to 2019 (pre-pandemic period) (P = 0.025). In the period from 2008 to 2015, 488 children were hospitalized at Department of Pediatrics, University Hospital of Split for acute intoxications, 272 (55.74 %) of them due to AAI, while in the period from 2016 to 2021 there were 218 intoxicated children, 71 (32.57 %) of them hospitalized due to AAI. In both examined periods, AAIs were more frequent among boys (63.60 % from 2008 – 2015, and 70.42 % from 2016 – 2021), most often among children aged 14 to 18 years (P < 0.001), during weekends and holidays (P < 0.001), and in outside places (P < 0.001). The average age was 15.95 ± 1.51 (in a period 2008 – 2015) and 16.17 ± 1.30 (in a period 2016 – 2021); blood alcohol concentration 2.003 ± 0.585 ‰ (in a period 2008 – 2015) and 2.15 ± 0.539 ‰ (in a period 2016 – 2021); the presence of injuries was detected among 11.03 % (in a period 2008 – 2015) and 23.94 % (in a period 2016 – 2021) children; and 6.25 % (in a period 2008 – 2015) and 8.45 % (in a period 2016 – 2021) children were positive for drugs in urine samples. The proportion of hospitalizations of children aged 0-18 due to AAI among all hospitalizations has signifficantly decreased from 2008 (1.33 %) to 2021 (0.23 %), with an expected decrease of 21.26 % in every next year. Conclusion: Although the incidence of AAIs among children in SDC is declining, the results of this study show a high prevalence of alcohol, drug and tobacco consumption among adolescents, depending on the type and place of school attendance. Therefore the results of this study can provide guidelines for more specific prevention programms among children and adolescents. The decrease in alcohol consumption among adolescents during the lockdown is a consequence of reduced socializing with friends and limited availability of alcohol during this period, and an indication that reducing the availability of psychoactive substances and maybe with better organization and offer of activities where young people can socialize, the incidence of risky behaviors among them can be reduced.