There have been many articles written about procrastination - some of which I have really meant to get around to reading but just haven't quite managed to just yet......however an interesting (and short!) article appears on the subject on the psychology today website in which Dr Joseph Ferrari, Associate Professor of Psychology at De Paul University in Chicago dispels the commonly held myth that procrastination is all about poor time management or lack of disciplined planning.
 
In the article Dr Ferrari hypothesises that procrastinators fall into 3 main categories:

• arousal types, or thrill-seekers, who wait to the last minute for the euphoric rush.
  
• avoiders, who may be avoiding fear of failure or even fear of success, but in either case are very concerned with what others think of them; they would rather have others think they lack effort than ability.
  
• decisional procrastinators, who cannot make a decision. Not making a decision absolves procrastinators of responsibility for the outcome of events.

"Telling someone who procrastinates to buy a weekly planner is like telling someone with chronic depression to just cheer up," insists Dr. Ferrari. 

http://www.psychologytoday.com/rss/pto-20030823-000001.html