Duration of untreated psychosis vs. N-acetylaspartate and choline in first episode schizophrenia: a 1H magnetic resonance spectroscopy study at 4.0 Tesla.

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.