Dopamine Transporters - ADHD, Bipolar, and Schizophrenia

Doctor Randy Blakely discusses the association between the dopamine transporter and ADHD, and discusses a possible relationship with bipolar disorder and schizophrenia.

It’s a tantalizing connection for us to pursue disorders beyond ADHD for several reasons. One, if we are correct and the inappropriate control of the dopamine transporter is a part of what is happening in ADHD, we have to remember that other behaviors and other behavioral disorders have long been studied for a contribution of dopamine to them: bipolar disorder, and mania, in particularly, and schizophrenia. For example, schizophrenia is treated with drugs that can block the actions of dopamine. So, on the one hand we have ADHD, which is treated with drugs that affect the ability of the neuron to get rid of dopamine, and you have schizophrenia, which is treated with drugs to prevent the actions of dopamine. So it’s possible that there may be some common mechanisms underlying both disorders, and epidemiologically there is certainly very clear evidence that ADHD and bipolar disorder run in families together. In fact, the mutation that we found in the two boys, one of the reasons why we held on to studies of it in the face of very normal data when we initially investigated it was that it had been found once before in a child with bipolar disorder. That was too much a coincidence for us; we’ve been studying rare genetic variants for some time in these proteins and similar proteins, and you know how low the probability is that you will find one in the first place. To find it twice or essentially to have the field find it twice in disorders where there is a statistical relationship between them was too strong for us to let it go. And so, we pursued our studies beyond the initial work, to eventually find this novel property that they cause.