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The dropout rates were higher than those reported in developed countries. Most participants in the cognitive therapy group refused to receive cognitive therapy so that the effect of cognitive therapy for these patients cannot be evaluated. The participants in the telephone intervention group had good compliance, but the effect of telephone intervention could not be confirmed, so that more studies are needed in the future. Consequently, interventions cannot be evaluated accurately in their preventing suicide attempts for patients who have attempted suicide in China at present.

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DEEP BRAIN STIMULATION (DBS) as a therapy in neurological and psychiatric disorders is widely applied in the field of functional and stereotactic neurosurgery. In this respect, experimental DBS in animal models is performed to evaluate new indications and new technology. In this article, we review our experience with the concept of experimental DBS, including its development and validation. An electrode construction was developed using clinical principles to perform DBS unilaterally or bilaterally in freely moving rats. The stimulation parameters were adjusted for the rat using current density calculations. We performed validation studies in 2 animal models: a rat model of Parkinson's disease (bilateral 6-hydroxydopamine infusion in the striatum) and a rat model of Huntington's disease (transgenic rats). The effects of DBS were evaluated in different behavioral tasks measuring motor and cognitive functions. The electrode construction developed allows experimental DBS to be performed in freely moving rats. With the current setup, electrodes are placed in the target in 70% to 95% of the cases. Using a rat model, we showed that bilateral DBS of the subthalamic nucleus improves parkinsonian motor disability, but can induce behavioral side effects, similar to the clinical situation. In addition, we showed that DBS of the globus pallidus can improve motor and cognitive symptoms in a rat model of Huntington's disease. Nevertheless, during the process of the development and validation of experimental DBS, we encountered specific problems. These are discussed in detail. Experimental DBS in freely moving animals is an adequate tool to explore new indications for DBS and to refine DBS technology.

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Huntington disease has been linked to increased dopaminergic neurotransmission in the striatum, and clinical studies have demonstrated that the associated chorea can be treated with dopamine antagonist or dopamine-depleting drugs. The origin of this hyperdopaminergic status is unknown. Because substantia nigra pars compacta and the ventral tegmental area are the main sources of striatal dopamine input, we hypothesized that changes in these regions relate to striatal dopaminergic alterations. Here, in a recently generated transgenic rat Huntington disease model that shows progressive striatal neurodegeneration and chorea, we found evidence of increased dopamine levels in the striatum. We also demonstrate more dopaminergic cells in the substantia nigra pars compacta and ventral tegmental area in these rats. These results suggest that increased striatal dopamine comes from these 2 main nuclei, and that it is not necessarily related to shrinkage of the striatum. The findings implicate increased dopamine input from these nuclei in the pathogenesis of chorea in Huntington disease.