Relationship between Bullying, Substance Use, Psychiatric Disorders, and Social Problems in a Sample of Kenyan Secondary Schools Victoria N. Mutiso 1 & Christine W. Musyimi 1,2 & Pauline Krolinski 3 & Charlotte M. Neher 3 & Abednego M. Musau 1 & Albert Tele 1 & David M. Ndetei 1,4 # Society for Prevention Research 2019 Abstract We aimed to investigate how direct bullying and victimization relate with substance use, the presence of psychiatric disorders, poor school performance, disruptive behaviors, and social problems among secondary school students. A cross-sectional study was conducted in 20 randomly selected mixed-day secondary school students in forms one to three in Machakos County, equivalent to students in grades 1 to 11. From a random starting point, every sixth student in the class was invited to participate. The Drug Use Screening Inventory (revised) (DUSI-R) and the Olweus Bully/Victim Questionnaire (OBVQ) were administered in a classroom-setting by trained research assistants with experience in data collection. Four categories, i.e., bully only, bully- victim, victim only, and neither bully nor victims (neutrals) were developed and problem density scores computed. Descriptive statistics, bivariate, and multinomial logistic regression analysis summarized the findings. Of the 471 students, 13.6% had not experienced bullying problems. Bully-victim was the most prevalent form of bullying. No significant gender differences were reported across categories. Bully-victims reported significant higher problem density scores in eight out of the nine problem domains, and effect sizes of the differences in problem scores between neutrals and bully-victims were larger compared with other categories. Behavioral and family system problem scores retained a significant relationship with bully-victim category (p < 0.001). A high prevalence of bullying problems was documented in both genders. However, bully-victims had a higher risk of multiple negative individual and environmental and social problems. Assessment of bullying problems is an indirect route to identifying significant youth problems. Bullying interventions should be multifaceted to address psycho-socio-behavioral problems. Keywords Direct bullying . Substance use . Psychiatric disorders . School performance . Kenya Introduction The World Health Organization (WHO) considers bullying as a major public health threat affecting people across all life stages (Srabstein and Leventhal 2010). It is described as a systematic misuse of authority and repeated violent attitude of peers with the intention to harm others (Lyznicki et al. 2004). Bullying illustrates unequal perceived or actual power distribution between the victim and the oppressor (Wolke and Lereya 2015). There has been recent interest to examine the long-term consequences of bullying during childhood and ad- olescence (Wolke et al. 2013). Past studies have documented both direct (physical and verbal) and indirect (psychological and relational) bullying patterns in schools globally, including Kenya (Due et al. 2005; Ndetei et al. 2007; Baldry 2004). According to local studies, bullying rates exceed the world’s average with two-thirds of school children in Kenya reporting to have experienced some form of bullying (Ndetei et al. 2007). Alongside school bullying, substance use (inclusive of al- cohol use) is a key problem among Kenyan youngsters. Moreover, drug abuse rates remain at a high level among the Kenyan youth (Chesang 2013), predisposing specifically those within the age group 16 and 30 years to irresponsible sexual practices or driving behavior, potentially leading to serious infections, injury, or death (Chesang 2013; Palen * David M. Ndetei dmndetei@amhf.or.ke 1 Africa Mental Health Research and Training Foundation, Mawensi Road, Off Elgon road, Mawensi Garden, Nairobi, Kenya 2 Vrije Universiteit, Amsterdam, Netherlands 3 Maastricht University, Maastricht, Netherlands 4 University of Nairobi, Nairobi, Kenya Prevention Science https://doi.org/10.1007/s11121-019-01014-4