Mean age of onset is in the mid-teens, and the onset after age 30 is uncommon. Although prevalence of SAD is greatest among young adults, for many sufferers the disorder is quiet chronic. Prevalence is also greater among persons who are much less educated and those who are single. Additionally, SAD is usually accompanied by comorbid disorders, such as mainly depression, substance abuse, or other anxiety disorders, which can further impair functioning. SAD has been shown in many studies and investigations to be associated with impairment and disability. SAD increases the risk of dropout from school, the work absence, unemployment, and utilization of social welfare, causing significant financial costs for the society. When compared with persons with no psychiatric disorder, having SAD is allied with financial dependency and increased rates of suicidal ideation.