Schizophrenia diagnoses are generally applied to individuals with a mix of behavioral problems and "abnormal or undesirable" thought patterns. It's a broad brush that isn't applied based on hard biological data like an MRI of the brain, but on observed and reported behavior at the discretion of the psychiatrist and rough adherence to DSM guidelines.

Typical treatments like Haldol, Thorazine, and Depakote have a blunting and depressive effect on the entire central nervous system. Treatments like shock therapy, cause severe memory loss and permanent brain damage.

These "treatments" are often paired with coercion, involuntary injections, confinement in psych wards, and court orders.

Many times LE will bring a civilian to a psych ward as a secondary or additional option to charging them with a crime. It's often seen as an additional tool in creating orderly communities, disciplining individuals that get out of line, and overall exerting control on society and free thought and action. Once a patient is admitted or diagnosed, they are strongly incentivized to align themselves and their behaviors to the values and expectations of the institutions and people that brought them there and control their release and treatment plans.

Even if schizophrenia had a biological signature it wouldn't be used in practice because they WANT the ambiguity and discretion to classify and medicate patients as they see fit.