The Molecule of More

THE MOLECULE OF MORE

Doctors try to maximize the benefits and minimize the

harms by getting the dose just right. They want to suppress

excess dopamine activity in the salience circuit without

overly suppressing the control circuit, which is responsible

for long-term planning. The goal is to give just enough med-

ication to block 60 to 80 percent of the dopamine recep-

tors. Additionally, when a dopamine surge occurs, signaling

something important in the environment, it would be nice

if the antipsychotic molecules got out of the way, just for

a moment, to let the signal get through. If you’re playing a

video game, trying to defeat the boss, or applying for a new

job, it would be nice to experience a little excitement to cre-

ate the motivation that pushes things forward.

Older antipsychotic medications don’t do this very well.

They stick hard to the receptor. If something interesting

happens and dopamine spikes, tough luck. The medication

has latched on so tight, no dopamine can get through, and

that doesn’t feel good. Being cut off from natural dopamine

surges makes the world a dull place and makes it hard to find

reasons to get out of bed in the morning. Newer drugs bind

more loosely. A surge of dopamine knocks the drug off the

receptors, and the this is interesting feeling gets through.

DRINKING FROM A FIRE HOSE

In  schizophrenia the  brain short-circuits, attaching salience to  ordinary 
things that ought to be familiar and therefore ignored. Another name
for this is low latent inhibition. Typically, latent is used to describe things
that are hidden, such as “a latent talent for music” or “a latent demand
for  flying cars.” The  way  it’s  used in  the  phrase latent inhibition is some-
what different. It’s  not  that  a  thing starts out  hidden, it’s  that  we make it
hidden because it’s not important to us.