"Suicidal ideation" or suicidal thoughts are the precursors of suicide, which is the leading cause of death among youth. Ideation or suicidal thoughts are categorized as: considering, seriously considering, planning, or attempting suicide and youth is typically categorized as individuals below the age of 25. Various research studies show an increased likelihood of suicide ideation in youth in the LGBT community. Factors involved in this propensity are peer victimization, parental disapproval, and bullying, as well as overall sentiments of undesirability due to LGBT identity. South Korea has the 10th highest rate of suicide in the world and the second in the OECD. Within these rates, suicide is the primary cause of death for South Korean youth, ages 10–19. While these rates are elevated, suicide ideation additionally increases with the introduction of LGBT identity. Stigmatization Stigmatization of LGBT identities results in negative self-feelings for the individual and increases their risk for self-harm and substance abuse. Studies done to measure the tolerance of homosexuality among South Korean University students found that of approximately 800 students surveyed, "68% would not be comfortable with having LGBT family members", "26.5% disagreed homosexuals could be good people", and "17.3% agreed homosexuality was shameful". The indicators of a disapproving or even repulsive opinion of LGBT individuals was gender, with men being more prone to disapprove than women. A second indicator of negative feelings towards LGBT individuals is religion, primarily in the realms of recognizing or approving of LGBT marriages. Harassment According to Rainbow Action, an South Korean Organization aimed at improving LGBT rights in South Korea, 80% of LGBT youth reported being the subjects of homophobic slurs from their peers and also approximate 80% reported hearing slurs from teachers. The harassment suffered by LGBT youth extends beyond merely verbal abuse. Studies show that there is a strong link between experience of violence for youth who have same-sex attraction, specifically in women who sleep with both men and women. Some studies suggest the main reason for suicidal ideation in youth is their exposure to violence in school. Effects of societal disapproval According to Joiner's Interpersonal Theory, feelings of isolation and perceived burdensomeness contribute greatly to an individual's propensity toward suicide ideation. Studies have found that in gay and lesbian South Korean youth, these two main factors are present at higher rates than in their heterosexual counterparts. Isolation is in reference to the continuous exposure to anti-LGBT rhetoric which