Why is it important to take a careful history of movement symptoms present before any antipsychotic medication was started, rather than assuming any movement abnormality seen during treatment is medication-induced?
A pre-treatment movement history is recommended precisely because some of these patterns, tardive dyskinesia in particular, are also seen in schizophrenia prior to any medication exposure. Without knowing what was present before treatment started, a clinician cannot confidently say whether a movement abnormality seen later reflects the medication, the underlying illness, or both.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 8, 'Motor Disorders'.