THE EFFECTS OF LITHIUM ON A POTENTIAL CYCLING MODEL OF BIPOLAR DISORDER

1. Although bipolar disorder constitutes a major public health problem , with a high risk of suicide and an economic cost exceeding that of u nipolar depression, it has received comparatively little attention, pa rticularly at the basic science level. Perhaps as a result of this neg lect, there is currently no animal model able to simulate the cyclicit y which is its defining characteristic. 2. Consequently, drug developm ent in this area is meager and has proceeded serendipitously rather th an empirically. 3. The authors have recently reported that repeated ex posure to cocaine and other stressors can induce an oscillation or cyc ling in a host of neurochemical and physiological systems. 4. In order to test whether such cycling might be of potential relevance to bipol ar disorder, the authors examined whether cocaine-induced cyclicity of amphetamine-evoked efflux of dopamine from slices of rat nucleus accu mbens and striatum and/or cocaine induced oscillation of a behavior, s tress-induced hypoalgesia, could be prevented by lithium, the agent of choice in treating this disease. 5. The authors report that prophylac tic treatment with lithium, completely and specifically prevented osci llations in each instance. This may represent an important initial ste p toward the development of the first cycling model of bipolar disorde r.