neglect during childhood are more likely to have physical ailments such as allergies, arthritis, asthma, bronchitis, high blood pressure, and ulcers. there may be a higher risk of developing cancer later in life, as well as possible immune dysfunction. exposure to violence during childhood is associated with shortened telomeres and with reduced telomerase activity. the increased rate of telomere length reduction correlates to a reduction in lifespan of 7 to 15 years. data from a recent study supports previous findings that specific neurobiochemical changes are linked to exposure to violence and abuse, several biological pathways can possibly lead to the development of illness, and certain physiological mechanisms can moderate how severe illnesses become in patients with past experience with violence or abuse. recent studies give evidence of a link between stress occurring early in life and epigenetic modifications that last into adulthood. adverse childhood experiences study main article: adverse childhood experiences possible ways for adverse childhood experiences such as abuse and neglect to influence health and well-being throughout the lifespan, according to the centers for disease control and prevention. the adverse childhood experiences study is a long-running investigation into the relationship between childhood adversity, including various forms of abuse and neglect, and health problems in later life. the initial phase of the study was conducted in san diego, california from 1995 to 1997. the world health organization summarizes the study as: "childhood maltreatment and household dysfunction contribute to the development – decades later – of the chronic diseases that are the most common causes of death and disability in the united states... a strong relationship was seen between the number of adverse experiences (including physical and sexual abuse in childhood) and self-reports of cigarette smoking, obesity, physical inactivity, alcoholism, drug abuse, depression, attempted suicide, sexual promiscuity and sexually transmitted diseases in later life." a long-term study of adults retrospectively reporting adverse childhood experiences including verbal, physical and sexual abuse, as well as other forms of childhood trauma found 25.9% of adults reported verbal abuse as children, 14.8% reported physical abuse, and 12.2% reported sexual abuse. data from the centers for disease control and prevention (cdc) and behavioral risk factor surveillance system corroborate these high rates. there is a high correlation between the number of different adverse childhood experiences (a.c.e.s) and risk for poor health outcomes in adults including cancer, heart attack, mental illness, reduced longevity, and drug and alcohol abuse. an anonymous self-reporting survey of washington state students finds 6–7% of 8th, 10th and 12th grade students actually attempt suicide. rates of depression are twice as high. other risk behaviors are even higher. there is a relationship between child physical and sexual abuse and suicide. for legal and cultural reasons as well as fears by children of being taken away from their parents most childhood abuse goes unreported and unsubstantiated. it has been discovered that childhood abuse can lead to the addiction of drugs and alcohol in adolescence and adult life. studies show that any type of abuse experienced in childhood can cause neurological changes making an individual more prone to addictive tendencies. a significant study examined 900 court cases of children who had experienced sexual and physical abuse along with neglect. the study found that a large sum of the children who were abused are now currently addicted to alcohol. this case study outlines how addiction is a significant effect of childhood abuse. psychological