as the neurobiological need to engage in sensation-seeking activities and impulsivity reduces. Studies show that tendencies of women to engage in risk-taking behavior often occur earlier in life when compared with men which may be linked with pubertal development. After reaching the peak of impulsivity and sensation-seeking behaviors women will often decline rapidly in their need to engage in these behaviors whereas men will steadily taper off as they develop gradual impulse control. While brain structures continue to develop during emerging adulthood, the cognition of emerging adults is an area that receives the majority of attention. Arnett explains, "Emerging adulthood is a critical stage for the emergence of complex forms of thinking required in complex societies." Crucial changes take place in their sense of self and capacity for self-reflection. At this stage, emerging adults often decide on a particular worldview and are able to recognize that other perspectives exist and are valid as well. While cognition generally becomes more complex, education level plays an important role in this development. Not all emerging adults reach the same advanced level in cognition because of the variety of education received during this age period. Abnormal development Much research has been directed at studying the onset of lifetime DSM disorders to dispel the common thought that most disorders begin earlier in life. Because of this reasoning, many people that show signs of disorders do not seek help due to its stigmatization. The research shows that those with various disorders will not feel symptoms until emerging adulthood. Kessler and Merikangas reported that "50% of emerging adults between the ages of 18 and 25 experience at least one psychiatric disorder." Not only is the emergence of various disorders prevalent in emerging adulthood, but the chance of developing a disorder drastically decreases at age 28. Seventy-five percent of any lifetime DSM-V anxiety, mood, impulse-control and substance abuse disorder begins before age 24. Most onsets at this age will not be, or become, comorbid. The median onset interquartile range of substance use disorders is 18–27, while the median onset age is 20. The median onset age of mood disorders is 25. Even disorders that begin earlier, like schizophrenia spectrum diagnoses, can reveal themselves within the age range of emerging adulthood. Often, patients will not seek help until several years of symptoms have passed, if at all. For example, those diagnosed with social anxiety disorder will rarely seek treatment