Stevens place it wrongly, being in schizophrenic state (10)
I believe the answer is:
cataleptic
'in schizophrenic state' is the definition.
Although both the answer and definition are adjectives, I cannot understand how one could define the other.
'stevens place it wrongly' is the wordplay.
'stevens' becomes 'cat' (I can't justify this - if you can you should give a lot more credence to this answer).
'wrongly' is an anagram indicator.
'place'+'it'='placeit'
'placeit' with letters rearranged gives 'aleptic'.
'cat'+'aleptic'='CATALEPTIC'
'being' acts as a link.
Can you help me to learn more?
(Other definitions for cataleptic that I've seen before include "that's not readily moved" , "in a stiff trance" .)