Symptoms of depression can include indecisiveness and distractibility, according to MayoClinic.com. Since organizing requires making decisions about where things should go, whether to keep or recycle items and how to categorize material, indecisiveness is a roadblock in effective organization.
Staying on task and keeping with an organizing project can be very difficult, or impossible, for a person who is easily distracted. The fatigue that may go along with major depression is also a detriment to organizing. The depressed person may not be able to muster up the energy to get started organizing and may find the energy required to keep the momentum going on their own just too overwhelming!
While mental health professionals are the best source of mental health counseling and treatment, the individual who is affected by both depression and disorganization may well benefit from working with a professional organizer who has experience and training in working with the chronically disorganized.
Have you observed a link between depression and disorganization? I would like to hear from you.