Re: Why do effects from LSD intensify when popping/cracking the neck or spine?

The main effects of LSD are concentrated on the neuro-transmitters 
Serotonin and norepinephrine; if you disturb the serotonin equilibrium 
(homeostasis) normally auditory and visual hallucinations occur .... so it 
could be that a part of the snapping sound is an auditory hallucination. 
Experience would say that because of the feeling that you can do anything (yoga 
is very easy under LSD's influence) with your body ... you will easily over 
stretch your spine.
 
About the flashback: as far as is known, lsd is metabolized in your body even 
before it starts to work, so there is no residue left that can cause 
flash backs. The general idea about flash backs is that the experience 
of the trip is so profound and intense that even a small envoirement cue 
can give you the feeling you're back in the state of the trip (something 
like a De ja Vu) simpler said: you're mind is playing tricks with you 
again!    

I don't know about he strychnine .... but you can probably get some answers 
at the alt.drugs pages on the web ...there are so many "home chemist" over 
there, some one will probably have an answers on your question .

Hoped to have helped you 
Greetings

Dv