N-acetylaspartate (NAA) has been associated with neuronal integrity and function, and
choline-containing compounds have been linked to neuronal membrane integrity. This study examined the influence of the duration of untreated
psychosis, duration of
prodromal symptoms and total length of untreated illness on these markers of neuronal loss or damage. In vivo 1H magnetic resonance spectroscopy data were acquired from 1.5-cc volumes in the left anterior cingulate and left thalamus of 19 never-treated first episode schizophrenic subjects using STEAM20 at 4.0 Tesla. Duration of untreated
psychosis, prodrome and total length of untreated illness were correlated with levels of NAA and
choline. No significant correlation was observed between NAA and duration of untreated
psychosis and untreated illness in both regions examined. Thalamic NAA negatively correlated with duration of
prodromal symptoms. A positive correlation between
choline and duration of untreated
psychosis was identified in both regions studied. Delays in treatment of psychotic symptoms of
schizophrenia were not associated with a reduction in markers of neuronal integrity or function in contrast to longer
prodromal periods, which were associated with lower NAA. Neuronal damage, potentially detectable via lower NAA, may be occurring before the onset of
psychosis. Increased
choline is associated with longer duration of untreated
psychosis and could indicate that
psychosis-related membrane alterations precede the appearance of NAA reductions observed by studies of chronic
schizophrenia.