It's clear from the second episode of Legion that one of the central conflicts of the series will be David's (Dan Stevens) mental well-being. More than his own unreliable narration, which provides the show with its unconventional narrative structure, the big question so far is whether David is actually mentally ill, or simply struggling under the weight of his telepathic powers. On the one hand, he's spent much of his adult life in psychiatric institutions for having delusions and psychotic episodes but, on the other, Melanie Bird (Jean Smart), the leader of secret mutant facility Summerland, is adamant that David's psychological issues stem from his mutant abilities and not schizophrenia.
We're shown that David's power is incredible - enough to make doors disappear or teleport an MRI machine - and that he can read minds. But these explorations of his powers have to explain some of the more jarring imagery that's been employed - specifically, the devil with the yellow eyes and David's distorted memories, from which chunks are missing and distorted.
Schizophrenia is a common mental illness that affects every aspect of a person's mind, from their behavior to how they think and feel, warping their ability to perceive and interact with the world. While a wide variety of signs exist (and an ever-expanding list of variations on the affliction), there are some broad, very commonplace symptoms such as hallucinations, delusions and trouble focusing or holding onto a thought. David exhibits all of these through-out the first two episodes, with scenes involving him engaging in a spirited dance routine with his fellow in-patients at Clockworks and him often hearing voices in his head and his exhibiting great difficulty in maintaining a conversation.
Some of David's experiences, like the voices, can and have been chalked up to his telepathy, but other instances aren't so simply delineated. In the outburst of telekinetic energy that destroyed his apartment, David could clearly see the devil with yellow eyes – a mysterious, short, yellow-eyed man whose presence seems to denote a severe reaction on David's part. The devil appears later right before David teleports the MRI machine, and can be seen when David and Syd (Rachel Keller) temporarily switch bodies causing a massive telekinetic surge. Horrifying as he is, the demonic creep brings with him a soundtrack of discordant jazz, further compounding the theme of cognitive distortion.
There is a common misconception that schizophrenia's main symptom is multiple personalities, but the correct term for this is dissociative identity disorder, or DID. In the source material, Legion (aka David)'s name derives from him having DID, with his powers split among the various personalities that inhabited his mind. After a terrorist incident causes his powers to manifest as a young child, Legion absorbs the mind of one of the assailants and drifts into a coma during which his mind shatters and compartmentalizes his powers among various different personas. His power directly causes his condition, and the two exist in a very uneasy tandem.
Legion comes at this from a slightly more complicated angle. A montage showing David's childhood into early-adulthood makes his mental breakdown apparent, but leaves its cause ambiguous. Showrunner Noah Hawley explained in an interview with Collider that David's situation is uniquely terrifying because:
"There’s something seditious to a mental illness whose key function is to convince you that you don’t have a mental illness. David biggest struggle is this idea that, if he allows himself to believe that he doesn’t have a mental illness, it was really his illness tricking him."
Schizophrenia and disorders like it frequently develop in individuals with no prior warning or trigger, and have the common side-effect of making sufferers unsure of what they can and can't believe. When one's reality could be an entire illusion manifesting in one's psyche that began at an unspecified moment during one's upbringing, choosing what to trust becomes a deeply existential question.
David's psychic abilities are numerous – "Chapter Two" ends with him using a form of mental projection – and in learning about them, he will inevitably have to try and draw a line between where they end and his outlying issues, if any, begin. He must do so knowing that his mind may be lying to him about his symptoms and his mentors may be too wilfully ignorant to get him the help he needs.
It's a precarious balance anchored by his romance with Syd. The couple's interactions are the only time we ever see David in any level of calm, their scenes acting as a brief reprieve from the scattered storytelling around them. More importantly, Syd provides an integral contrast to David's issues: per Hawley, she developed some personality issues by growing up as a misunderstood mutant:
"Even though Syd didn’t have an anti-social personality disorder to start with, she certainly has some issues now, after having spent ten years with these powers and being treated the way she’s been treated."
Syd doesn't have a diagnosis like schizophrenia, but she is a living example of how having a severe mutation, in her case one that activates upon any skin on skin contact, leads to a self-perpetuating cycle of stigma and mental ill-health. She understands having to be both a mutant and a sufferer of mental illness and their relationship may prove to be the conduit David needs to adequately assess his own needs. David listens to Syd, David trusts Syd, and perhaps if he can at least hold onto their kinship, he can use that to establish some sense of clarity and mental coherence.
Unfortunately, it will likely not be so simple. Legion is a show built on the tricky and the uneasy, and its depiction of mental illness is intricate. There's an active and foreboding authenticity to the characters and their struggles, the series resisting any kind of simplicity or shortcut. What we've seen of David's still largely untapped powers tells us that he has a tremendous journey ahead of him if he is control them, and as such the question the series is asking is less “is David schizophrenic?” and more “if David has schizophrenia, what difference would it really make?” - and that's the most challenging reality of all.
Legion airs Wednesdays @10PM on FX.