Regional cerebral blood flow and negative/positive symptoms in 24 drug-naive schizophrenics

SPECT/PET studies in schizophrenia revealed inconsistent changes of regional cerebral blood flow (rCBF). Frontal hyperperfusion as well as hypoperfusion are described. This study was undertaken to investigate the relations between rCBF, psychopathology according to PANSS and effects of neuroleptic therapy.

Twenty-four drug-naive acute patients with a first manifestation of schizophrenia were examined with 99mTc-HMPAO brain SPECT and assessed according to PANSS. Of these, 22 were controlled again after neuroleptic treatment. Following attenuation correction, region-to-cerebellar count ratios were obtained from 98 irregular regions of interest drawn in all slices (6.25 mm). The ratios were compared to 20 control subjects, and changes lying outside of 2 s.d. were considered abnormal.

In different drug-naive patients, hyperperfusion as well as hypoperfused patterns were found. In drug-naive patients, the seven subscores of positive symptoms (pos 1-7) in PANSS showed different correlations to rCBF: Formal thought disorders (pos 2) and grandiosity (pos 5) were positively correlated to bifrontal and bitemporal rCBF (r = +0.59 to +0.70). Delusional ideas (pos 1), hallucinatory behavior (pos 3) and suspiciousness (pos 6) demonstrated a negative correlation to bifrontal, cingulate, left temporal and left thalamic rCBF (r = -0.59 to -0.66). Stereotyped ideas (neg 7) as a negative symptom showed a negative correlation to left frontal, left temporal and left parietal rCBF (r = -0.59 to -0.65). No correlations were found between residual positive symptoms and rCBF after neuroleptic treatment and clinical improvement, but all negative symptoms (neg 1-7) had a negative correlation to bifrontal, bitemporal, cingulate, basal ganglia and thalamic rCBF (r = -0.59 to -0.74).

Our results illustrate that different positive symptoms are accompanied by different rCBF values: some induce hyperperfusion, others hypoperfusion. After therapy (and reduction of positive symptoms), only negative symptoms correlate exclusively to hypoperfusion. This may be the crucial factor in explaining inconsistencies of past results in perfusion pattern in drug-naive schizophrenic patients.