Looks like an iatrogenic case.
Celexa being an SSRI, and Effexor, a potent SNRI, must have messed
up your husband's serotonin regulatory system. One can't just simply
switch from one to the other like candy, without tapering off the first
and then introducing the second at a low dose and then titrating it up slowly.
These are powerful drugs.
The nonstop twitching is obviously tardive dyskinesia, a typical side effect
of psychotropic drugs, usually neuroleptics like the phenothiazines, but can
also happen with antidrepressants.
If you read this study :
" 5-HT may be pivotal to the pathogenesis and therapy of ALS.
Furthermore, cerebrospinal fluid levels of tryptophan, a precursor of 5-HT, are
decreased in patients with ALS and plasma concentrations of tryptophan are also
decreased with the lowest levels found in the most severely affected patients. "
" Furthermore, 5-HT is a precursor of melatonin, which inhibits glutamate release
and glutamate-induced neurotoxicity. "
" Thus, progressive degeneration of 5-HT neurons affecting motoneuron activity
constitutes the prime mover of the disease and its progression and treatment
of ALS needs to be focused primarily on boosting 5-HT functions. "
" .... the 5-HT precursor 5-hydroxytryptophan (5-HTP) improved locomotor function
and survival of transgenic SOD1 G93A mice, an animal model of ALS. "
Serotonergic mechanisms in amyotrophic - PubMed Mobile
I believe he can't swallow, otherwise you could try getting some 5-HTP supplements
from the health food stores and giving it to him.