Medication effects in neuroimaging studies of bipolar disorder.
OBJECTIVE
Neuroimaging studies are promising components for a new diagnostic framework for bipolar disorder, but a major issue is the potential confound of psychotropic medication upon experimental measures. Withdrawing all individuals from medication and examining only unmedicated individuals may be clinically unfeasible, and examining only unmedicated individuals may render findings less generalizable.


METHODS
The authors review structural and functional neuroimaging studies of medicated and unmedicated patients with bipolar disorder to discern the possible confounding effect of medication.


RESULTS
Findings from studies identified on MEDLINE that included medicated individuals with bipolar disorder indicated either no significant effect or ameliorative effects of psychotropic medications on abnormal structural and functional neuroimaging measures relevant to pathophysiologic mechanisms of the disorder. Different strategies for assessing medication effects are compared.


CONCLUSIONS
Neuroimaging studies of bipolar disorder ideally should recruit both unmedicated and medicated individuals. Individuals who are unable to tolerate medication withdrawal likely have more severe illness and are especially informative for research examining biomarkers of illness and treatment response.
Phillips
Mary L
ML
Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA. phillipsml@upmc.edu
Travis
Michael J
MJ
Fagiolini
Andrea
A
Kupfer
David J
DJ
D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology / Q000627:therapeutic use; D054316:Biomarkers, Pharmacological; D001714:Bipolar Disorder / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D001921:Brain / Q000187:drug effects* / Q000503:physiopathology; D010054:Brief Psychiatric Rating Scale; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D016651:Lithium Carbonate / Q000494:pharmacology / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D009682:Magnetic Resonance Spectroscopy / Q000706:statistics & numerical data*; D008297:Male; D017397:Prefrontal Cortex / Q000187:drug effects / Q000503:physiopathology; D011619:Psychotropic Drugs / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D012107:Research Design; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D014150:Antipsychotic Agents; D054316:Biomarkers, Pharmacological; D011619:Psychotropic Drugs; D016651:Lithium Carbonate