Impulsivity is a term that psychologists and psychiatrists use to describe a tendency to act without thinking or regard for the consequences of one\u2019s behavior. All humans naturally have impulses, but most children and teenagers gradually learn to consciously control those urges and comply in meaningful ways with the social norms of their culture. Current evidence indicates that many teenagers who start smoking have higher levels of impulsivity than their non-smoking peers. According to the results of a study published in 2011 in the journal Nicotine and Tobacco Research, teens and young adults who experience declines in impulsivity levels are able to quit substance abuse, including nicotine, more often than their peers who don\u2019t experience similar declines in impulsivity. Impulsivity as a Symptom of Mental Illness Impulsivity is not a form of mental illness. Instead, in a mental health context, it functions as a symptom in a wide variety of diagnosable illnesses, including conditions such as attention deficit-hyperactivity disorder (ADHD), bipolar disorder, antisocial personality disorder, borderline personality disorder (BPD), narcissistic personality disorder, kleptomania, pyromania and intermittent explosive disorder. Outside of a strict mental health context, impulsivity can also be viewed as a natural human instinct that can have either beneficial or harmful consequences. The specific part of the brain responsible for impulse control is called the prefrontal cortex (PFC). As its name implies, this region sits toward the front of the brain; it spans the brain\u2019s midline and includes portions of both frontal lobes. In addition to impulse control, the PFC is responsible for a variety of other tasks commonly referred to as \u201cexecutive functions.\u201d Examples of these functions include the ability to solve problems, focus attention, plan for the future, balance the pros and cons of a given activity, control intense emotions, make behavioral changes when necessary or appropriate, and keep multiple factors in mind when making complex or detailed decisions. Of all of the brain\u2019s areas, the prefrontal cortex is one of the last to fully develop. Current evidence indicates that fully mature operation of the PFC only begins when human beings reach their mid-20s. Impulsivity and Smoking In the study published in Nicotine and Tobacco Research, a team of researchers from the University of Missouri examined smoking behaviors in a group of teens and adults ranging in age from 18 to 35. They also reviewed psychological profiles of the study participants and identified the presence of key personality characteristics such as impulsivity and a \u201cneurotic\u201d tendency toward emotionally intense forms of anxiousness and negativity. After reviewing the data, the authors of the study concluded that 18-year-olds who smoke have higher levels of impulsivity than their peers who don\u2019t smoke; 18-year-old smokers also have higher levels of emotionally charged negativity and anxiousness than their non-smoking peers. The University of Missouri researchers also examined rates of smoking cessation among the study participants. They concluded that the people most likely to quit smoking are individuals between the ages of 18 and 25 who experience significant drops in their impulsivity levels, as well as in their levels of anxiousness and negativity. In addition, they concluded that people who don\u2019t stop smoking by the age of 25 generally start making a shift from impulse-based smoking to habit-based smoking. The shift depends heavily on addiction-related factors such as nicotine cravings and tolerance to nicotine\u2019s mind-altering effects. A New Focus for Anti-Smoking Campaigns The prefrontal cortex, which acts as the brain\u2019s resource center for impulse control, fully develops by the time a person reaches the age of 25. This age roughly coincides with the upper age range of smokers who are likely to experience a reduction in their impulsive behaviors and quit using nicotine. The authors of the study believe public health officials can use this information to devise anti-smoking campaigns specifically designed to address impulsivity in teenagers. Essentially, such campaigns could influence teen behavior while the brain is still in a critical phase of development. However, the study authors also emphasize that substance abuse issues are inherently complex, and no single approach will likely curb the overall rate of teen tobacco use.