I think 4 months is enough to see some progress… and I would look for another psychiatrist and get a second assessment. Cloz / Leponex doesn’t seem to me to be the best way to deal with sz with neg symptoms. I would suggest looking into Abilify arapiprasole or Latuda lurasidone, at least for a month or two to see if one of them can lift you up a bit. (Not sure of the brand names in Europe, but I just gave your the generic names of each one.)
Likewise, I would say that the beta blockers may be adding to the neg symptoms, and that the sympathetic autonomic pitch (that results in the cardiac dysrhythmia you’re dealing with due to the anxiety) could better be reduced by other means. But don’t suddenly stop taking them until better solutions are found (see below).
I would definitely look into this: Sarcosine Reduces Symptoms in Schizophrenia
I’d also look into getting psychotherapeutic help to knock down the cycle of thoughts, feelings and behaviors I’m pretty sure is contributing to the anxiety and depression you have described.
REBT – Rational emotive behavior therapy - Wikipedia
Schematherapy – Schema therapy - Wikipedia
Learned Optimism – Learned optimism - Wikipedia
Standard CBT – http://www.beckinstitute.org/what-is-cognitive-behavioral-therapy/About-CBT/252/
DBT – http://behavioraltech.org/resources/whatisdbt.cfm
MBSR – Welcome to the Mindful Living Blog
ACT – ACT | Association for Contextual Behavioral Science
MBBT – An Introduction to Mind-Body Bridging & the I-System – New Harbinger Publications, Inc
10 StEP – Pair A Docks: The 10 StEPs of Emotion Processing
SEPT – Somatic experiencing - Wikipedia
SMPT – Sensorimotor psychotherapy - Wikipedia