DSM-IV Diagnosis of Leonard's Mental Condition

Rating: 10/10 (1 December 2007)

The Limited Edition DVD Set of Memento released in 2002 includes a sheet of paper in the box with a blank space labeled "diagnosis". It seems that the director is literally inviting us to make a diagnosis of Leonard. I intend to do that here, but doing so will necessitate revealing some spoilers, so be forewarned before reading further. I only have room here for a brief synopsis. For a fuller treatment, see the commentary about Memento at my blogsite (rboothe.wordpress.com).
The DSM-IV is the standard reference manual used by psychiatrists and psychologists when diagnosing a mental disorder. One of the diagnostic conditions listed in the DSM-IV is amnesia, a cognitive disorder secondary to brain injury or trauma. Can we fit Leonard into this diagnostic category? The short answer is no! Let me elaborate.
Consider first, the relationship between Leonard and Sammy. The character Sammy is either Leonard's alter ego, or was someone Leonard once met whose persona he has tried to assume as his own. Most of what Leonard tells us about Sammy during the film is actually a description of Leonard (himself). We know that Leonard himself went by the name "Sammy" sometimes, as evidenced in the scene where the character Jimmy is dying and calls out, "Sammy", towards his murderer, Leonard. The character Teddy informs us that "Sammy" did not have a wife, and that all of Leonard's stories about "Sammy's wife" having diabetes were really stories about Leonard's wife. Finally, the director threw in an even more explicit clue in the form of a flashback. In the scene where Leonard is discussing how "Sammy" was committed to a mental institution, we are shown flashback in which we see "Sammy" sitting in the hospital. At the very end of the flashback, the director inserts a few frames in which the person in the mental hospital is actually Leonard.
There are several lines of evidence that "Sammy" did not really have amnesia. Leonard tells us that, in his role as insurance investigator, he concluded there was "no physical reason that should prevent Sammy from making new memories". We are also told that "Sammy's wife" was skeptical about whether or not he really had memory loss. Finally, we are told that the doctors who examined "Sammy" were skeptical about his memory loss.
Lets tentatively conclude that since "Sammy" probably did not really have amnesia, that means Leonard did not have amnesia. If that tentative conclusion is correct, we can expect that the director must have provided a clue  Some example where Leonard messed up and revealed some fact that he could not have known if he really had amnesia. This clue shows up in the critical scene where Leonard refers to the motel manager, Burt, by name. As an amusing aside, I would like to mention that the IMDb site for Memento lists this as "a goof in continuity". However, this is a "goof ", as opposed to a "clue", only if one presupposes that Leonard really had amnesia! So, if the evidence does not allow us to diagnose Leonard with the condition of amnesia, what mental condition did he have? Lets consider another diagnostic condition described in the DSM-IV, Antisocial Personality Disorder (APD). In layman's terms, individuals diagnosed with APD are often called psychopaths. They lack empathy for the pain and suffering of others, and are able to inflict physical and emotional pain without feeling any remorse. These individuals also enjoy playing elaborate con games, often simply for thrills rather than for personal gain.
Lets consider the possibility that Leonard was a psychopath who was playing an elaborate game in which he pretended to have anterograde memory loss. Perhaps he had actually once known someone named Sammy who had the condition. Or perhaps he just heard about the condition somewhere, became intrigued by it, and went to the library to study up about it. Either way, he decided to initiate an elaborate game where, in every situation in which he found himself, he imagined what a person with this form of amnesia would do, and then acted in the same way. He played this game to the limit, regardless of where it led, including if it required him to drink other peoples spit, or hurt or kill other individuals, including his own wife.
What evidence in the film supports this possibility? Consider a key diagnostic feature of individuals with APD, as specified in DSM-IV. They do not exhibit normal fear responses, and as a result have trouble learning to alter their behavior based on punishment. For example, if a normal person were given an electric shock each time he chose a triangle over a square on a psychological test, that person would quickly learn to choose the square instead of the triangle on subsequent tests. A person with APD would have trouble learning this task. Does this test sound familiar? It was the test failed by the character "Sammy", and that led to "Sammy's" diagnosis and subsequent commitment to a mental hospital.
Is there any direct evidence for this diagnostic trait in Leonard? There is a scene early in the film where Leonard runs into the glass at the entry door of the motel where he has been staying. Ouch! He does this because the door opens outward but he tries to push on it. A "normal" individual might do this once, or perhaps twice, but then quickly learn to alter his behavior so as to avoid continuing to be punished. An individual with APD would take much longer. At this point in the story, Leonard has been staying at this same motel for at least days, possibly weeks. Bingo! I think I have my diagnosis.