A therapist is working with a new client, a 38-year-old man who had significant difficulties with inattention and hyperactivity throughout his childhood. The client describes feeling socially isolated, having gone through a recent divorce, and struggling with a substance use disorder (not involving alcohol). Based on the known findings from a major longitudinal study comparing adults with and without a history of childhood attention-deficit/hyperactivity disorder, are this client's experiences typical? Explain your reasoning.