Patent ID: 7906300

Claim:
A method for diagnosing attention-deficit/hyperactivity disorder (ADHD) in a human patient, comprising: (a) obtaining a ratio of (i) the mean membrane potential of cells of a test human patient incubated in vitro in the presence of a compound that alters Na + K + ATPase activity, but in the absence of K + , to (ii) the mean membrane potential of cells of the test human patient incubated in vitro in the absence of the compound that alters Na + K + ATPase activity, but in the presence of K + ; and at least one of the following steps (b) or (b′): (b) comparing the ratio obtained in (a) to a control ratio, wherein the control ratio is the ratio of (iii) the mean membrane potential of corresponding control cells of one or more humans known to not have ADHD incubated in vitro in the presence of a compound that alters Na + K + ATPase activity, but in the absence of K + , to (iv) the mean membrane potential of corresponding control cells of one or more humans known to not have ADHD incubated in vitro in the absence of the compound that alters Na + K + ATPase activity, but in the presence of K + , wherein when the ratio obtained in (a) is significantly higher than the control ratio obtained in (b), said test human patient is diagnosed as having ADHD; (b′) comparing the ratio obtained in (a) to a ADHD control ratio, wherein the ADHD control ratio is the ratio of (v) the mean membrane potential of corresponding ADHD control cells of one or more humans known to have ADHD incubated in vitro in the presence of a compound that alters Na + K + ATPase activity, but in the absence of K + , to (vi) the mean membrane potential of corresponding ADHD control cells of one or more humans known to have ADHD incubated in vitro in the absence of the compound that alters Na + K + ATPase activity, but in the presence of K + , wherein when the ratio obtained in (a) is not significantly different than the ADHD control ratio obtained in (b′), said test human patient is diagnosed as having ADHD, wherein each mean membrane potential is determined by incubating the cells in vitro in buffer comprising a potential-sensitive dye, resuspending the cells in potential-sensitive dye free-buffer, and measuring cell fluorescence.