Most major pharmaceutical companies report a surge in research on new
psychiatric drugs.
One of the most active laboratories is at the Neurogen Corp. in Branford,
Conn. Neurogen, in conjunction with Schering-Plough, is testing a compound
that affects only the dopamine D4 receptor, which is thought to be involved
in the cognitive aspects of schizophrenia. The hope is that the drug might
make it easier to hold a thought and pay attention. Upjohn and Sanofir
Winthrop are among other companies that have dopamine receptor-specific
compounds in the research pipeline for the treatment of schizophrenia.
Pfizer, in partnership with Neurogen, is developing drugs that affect GABA
receptors. GABA is the major inhibitory neurotransmitter; it slows down
the
activity of the others. GABA is involved in anxiety disorders; tranquilizers
like Valium act on GABA receptors. The new medication may one day replace
tranquilizers like Valium, calming patients, without sedating them.
Neurogen is also developing a drug that acts on receptors for CRF, or
corticotropin releasing factor, which the brain secretes in response to
threat or emergencies to set off the fight-or-flight response. A drug that
targets CRF receptors might be used to treat post-traumatic stress disorder,
for which there is now no specific medication at all. It might also be
useful
for treating anxiety symptoms associated with depression and for panic
disorder.
Neuropeptides like beta-endorphin are among the many neurotransmitters
that regulate emotion. Neurogen is also testing a drug that would treat
depression through acting on Neuropeptide Y, which helps regulate
norepinephrine. Some antidepressants work by blocking the reuptake of
norepinephrine.
Merck is testing compounds for treating depression that target a specific
serotonin-2 receptor that is thought to have a role in psychotic
hallucinations.