Dopamine D2 receptor occupancy measured by single photon emission computed tomography with 123I-Iodobenzamide in chronic schizophrenia.
Single photon emission computed tomography (SPECT) with 123I-iodobenzamide (123I-IBZM) was used to study 22 chronic schizophrenic patients. The patients, who were receiving maintenance therapy with typical neuroleptics, had not shown any significant improvement since their admission to the hospital. Basal ganglia/frontal cortex ratios of the uptake of 123I-IBZM did not show significant differences on the basis of neuroleptic dosage in chlorpromazine equivalents. There were, however, significant differences in 123I-IBZM uptake in the basal ganglia among patients characterized by negative, mixed, and positive symptoms of schizophrenia. Although only a small number of patients had shown a positive response to treatment by the time of discharge, D2 receptor blockade was significantly higher in responders than in nonresponders. In addition, there was an inverse correlation between reduced activation as measured by the Brief Psychiatric Rating Scale and the basal ganglia/frontal cortex ratio. These findings suggest a complex pathogenetic link between the blockade of dopamine D2 receptors and psychopathology in chronic schizophrenic patients. SPECT studies with 123I-IBZM appear to have prognostic value in identifying chronic schizophrenic patients who respond poorly to neuroleptic treatment.
Volk
S
S
Department of Clinical Psychiatry II, Johann Wolfgang Goethe Universität, Frankfurt am Main, Germany.
Maul
F D
FD
Hör
G
G
Schreiner
M
M
Weppner
M
M
Holzmann
T
T
Pflug
B
B
D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001479:Basal Ganglia / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D001549:Benzamides; D002908:Chronic Disease; D003287:Contrast Media; D018492:Dopamine Antagonists; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011569:Psychiatric Status Rating Scales; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000502:physiology*; D012559:Schizophrenia / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon
D014150:Antipsychotic Agents; D001549:Benzamides; D003287:Contrast Media; D018492:Dopamine Antagonists; D007457:Iodine Radioisotopes; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide