SPOILER *********************** Was Mrs Jankis Leonard's memory for Mrs Shelby's diabetes?

Rating: Null/10 (18 April 2001)

SPOILER
If Mrs Jankis didn't exist and Mrs Shelby was a diabetic, then did Leonard give his wife too many insulin shots and therefore kill her? If not, and the simple truth was that she was killed by a random junkie breakin and not by Leonard, then what is the purpose of Teddy's instruction to Leonard that Mr Jankis didn't have a wife? Did Mr Jankis exist? Was Leonard the victim of an accident which removed his short term memory and did his wife not believe him?
Would someone be able to clear that up for me, please? Perhaps the screenwriter?
Thanks.
Apart from that ambiguity, I watched the film with interest. The last film to make an impact on me was "Wonderland". The way London was depicted in that film was truly disturbing. Characters living lives of noisy desperation. Memento left an impression because it raised so many plot questions and of course the big issue of lying to ourselves in order to carry one. As Jack said - "you can't handle the truth".
Oh and yes, Guy Pearce is good to watch. He needs a dialogue coach to enrich his vocals. The voice was a bit thin. He does, however, have screen presence and you can't buy that.