Risks associated with energy drinks include:
caffeine overdose, symptoms -palpitations, high blood pressure, nausea & vomiting, convulsions & even death. Type 2 diabetes, cardiovascular system effects in children and adolescents, as well as alarming changes in behavior, to name a few.
More details
www.nhs.uk/news/2014/10October/Pages/Warnings-issued-over-energy-drink-risks.aspx
journal.frontiersin.org/article/10.3389/fpubh.2014.00134/full#h11
www.caffeineinformer.com/caffeine-overdose-facts-and-fiction