"The cumulative results of the brain's chemical effects are not well understood. In the 1989 edition of the standard Comprehensive Textbook of Psychiatry, for example, one finds this helpful formula: a depression score is equivalent to the level of 3-methoxy-4-hydroxyphenylglycol (a compound found in the urine of all people and not apparently affected by depression); minus the level of 3-methoxy-4-hydroxymandelic acid; plus the level of norepinephrine; minus the level of normetanephrine plus the level of metanepherine, the sum of those divided by the level of 3-methoxy-4-hydroxymandelic acid; plus an unspecified conversion variable; or, as CTP puts it: "D-type score = C1 (MHPG) - C2 (VMA) + C3 (NE) - C4 (NMN + MN)/VMA + C0." The score should come out between one for unipolar and zero for bipolar patients, so if you come up with something else--you're doing it wrong." --