For doctors who treat illnesses that strike from the neck down, a patient's symptoms are only the first step toward a diagnosis. No sooner do they hear 'it hurts when I climb stairs' than they order blood work, x-rays or other tests. In psychiatry, though, the laundry list of symptoms is it, the only basis for diagnosis. Maybe that helps explain why 70% of patients with bipolar disorder are misdiagnosed, as are up to half of women with depression. They take drug after drug, taking each dose of each medication for four to six weeks until one works or they give up, wasting money and time while their suffering continues. It's hard to avoid the sense that psychiatry could stand to be dragged into... well, let's start with the 20th century.The American Psychiatric Association is updating its immense diagnostic manual, which offers 20 forms of bipolar disorder alone. "But it's still just a checklist of symptoms, which different physicians can interpret differently," says psychiatrist James Greenblatt, who directs the eating-disorders unit at Waltham Hospital in Massachusetts. For him and a growing number of psychiatrists, the search for a modern, objective diagnostic tool has led to the past: the electroencephalogram, first used in 1929 to record the brains electrical activity.
For an EEG, which typically costs about $150 and takes 45 minutes, a patient has about 20 electrodes pasted to his scalp, where they measure the electrical activity of neurons - brain waves - directly beneath. In the 1980's, researchers tried to base diagnoses on EEGs, but it didn't work. The same squiggles could mean different illnesses, and one illness could be marked by different EEG's. The new use of EEG's skips the diagnosis and goes straight to a recommended treatment. An EEG is compared to a database that includes 13,000 pairings of EEGs with which drugs helped in each case. A California company called CNS Response, which runs the database, finds a match and sends the physician an analysis indicating which drugs patients with that EEG are sensitive or resistant to.
That would be humdrum if, say, the analysis said 'Prozac' for a patient with depression. But according to the studies of hundreds of patients "in some three quarters of patients the EEG database leads the physician to something he wouldn't have thought of," says CNS President Len Brandt. The EEG matches aren't perfect. For about one quarter of patients, the $500 analysis suggests treatments that work no better than what they'd already tried. It has proved most beneficial in stubborn cases and in those with no obvious first line drug, such as eating disorders and addiction.
One reason for the sometimes odd pairings of illnesses and drugs is that many different brain states can produce the same mental symptoms, and many different symptoms can arise from the same brain state. The mind has not yielded all its mysteries quite yet.
(Edited for space. Thanks to Al & Judy Peraino for this!)
