It is unlikely that these participants abused substances prior to their AMO; therefore, including them in the analysis may confound the findings. Later in the disease process, the cognitive deficits progress to more widespread global subcortical dementia. Drugs abused by humans preferentially increase synaptic dopamine concentrations in the mesolimbic system of freely moving rats. The second group of symptoms, which occur early in disease progression, after involuntary movements, consists of a group of clinical findings that are composed entirely of mental and emotional symptoms, including sadness, depression, and difficult to get along with. Samml Psychiatr Neurol Einzeldarst,