Neuroimaging and cognitive correlates of co-morbid schizophrenia and methamphetamine abuse
In the past decade the use of the stimulant methamphetamine has increased in schizophrenia patients as well as the general population. In persons without a psychiatric diagnosis methamphetamine is known to be neurotoxic to dopaminergic rich frontostriatal brain regions, including the anterior cingulate cortex and the prefrontal cortex with accompanying deficits in attention and executive control. Little is known however about the additive effects of methamphetamine abuse on brain function and cognitive control in schizophrenia patients. Our research program is examining the effects of methamphetamine abuse on brain function and attention in schizophrenia patients using Functional Magnetic Resonance Imaging [fMRI], magnetic resonance spectroscopy [MRS] and experimental measures of cognitive control. The use of MRS in conjunction with fMRI will determine whether or not neuronal pathology as measured with MRS is linked to functional brain activation as measured by fMRI during tests of cognitive control. These data will provide insight into the neural substrates underlying attentional control and may contribute to clinical interventions in those schizophrenia patients who abuse stimulants.
Neural and cognitive sequelae of methamphetamine abuse
There is increasing evidence that methamphetamine is neurotoxic to dopaminergic frontostriatal brain regions with corresponding deficits in selective attention and cognitive control. Our research program is investigating the relationship between alterations in brain function and attentional control in methamphetamine abusers. We are employing magnetic resonance spectroscopy [MRS] and diffusion tensor imaging [DTI] in conjunction with sensitive computerized measures of attention to examine these links. Our findings thus far indicate a dysregulation of attentional control associated with long-term methamphetamine abuse. Such breakdowns in attentional control may contribute to behaviors associated with maladaptive decision-making often associated with drug-seeking behavior. Careful characterization of cognitive functioning is relevant to the treatment of substance abuse as many treatment programs rely on cognitive behavioral therapy as part of their intervention approach.