ADHD causes many individuals to have difficulty concentrating on a single issue. This can lead to a lack of success in work because of an inability to meet deadlines or stay on task. It can also be detrimental to relationships because of the inability honor a commitment or a goal. The spouse may interpret this as a lack of concern about the relationship but the ADHD individual may not understand why his or her partner is upset.
The other side of the lack of focus for ADHD individuals is excessive focus, amounting to almost a compulsion. These people become so focused on a particular task that they lose sight of all else. Particularly in a home situation where the individual may be responsible for minding the children or some similar task, their excessive focus can become hazardous.