diagnostic criteria of ADHD, an individual must display: at least six inattentive-type symptoms for the inattentive type at least six hyperactive-type symptoms for the hyperactive-impulsive type all of the above to have the combined type The symptoms (see below) were required to have been present since before the individual was seven years old, and must have interfered with at least two spheres of his or her functioning (at home and at school or work, for example) over the last six months. The DSM-IV criteria for ADHD were, however, tailored towards the type of symptoms that children would show, and might therefore have underestimated the prevalence of ADHD in adults. In 2013, the newer DSM-5 reviewed some of these criteria, with more lenient requirements for the diagnosis, especially in adults, and the age limit for symptoms first arising raised to twelve years. Signs and symptoms ADHD is a chronic condition, beginning in early childhood that can persist throughout a person's lifetime. It is estimated that 33–66% of children with ADHD will continue to have significant ADHD-related symptoms persisting into adulthood, resulting in a significant impact on education, employment, and interpersonal relationships. Individuals with ADHD exhibit deficiencies in self-regulation and self-motivation which in turn foster problematic characteristics such as distractibility, procrastination, and disorganization. They are often perceived by others as chaotic, with a tendency to need high stimulation to be less distracted and function effectively. The learning potential and overall intelligence of an adult with ADHD, however, is no different from the potential and intelligence of adults who do not have the disorder. Whereas teachers and caregivers responsible for children are often attuned to the symptoms of ADHD, employers and others who interact with adults are less likely to regard such behaviors as a symptom. In part, this is because symptoms do change with maturity; adults who have ADHD are less likely to exhibit obvious hyperactive behaviors. Instead, they may report constant mental activity and inner restlessness as their hyperactivity internalizes. Symptoms of ADHD (see table below) can vary widely between individuals and throughout the lifetime of an individual. As the neurobiology of ADHD is becoming increasingly understood, it is becoming evident that difficulties exhibited by individuals with ADHD are due to problems with the parts of the brain responsible for executive functions (see below: Pathophysiology). These result in problems with sustaining attention, planning, organization, prioritization, time management, impulse control, and decision