The course of negative symptoms over the first five years of treatment: Data from an early intervention program for...

Cross-sectional studies suggest that negative symptoms are constituted by separable domains of reduced expressiveness and reduced motivation, but there is little data on the longitudinal course of these symptoms. We examined evidence for differences in the course and correlates of these two domains in a prospective study of patients presenting with a first episode of psychosis.

Of 132 patients who were followed up for five years, it was possible to monitor reduced expressiveness and motivation on a weekly basis for 127. Information on treatment delay, premorbid adjustment, intellectual functioning, anxiety, depression and psychosocial functioning were also collected.

Over the five year follow-up, symptoms of reduced motivation occurred in 95.3% of patients and reduced expressiveness in 68.5%; and deficits in motivation were more likely to be unremitting (15.7%) than expressive deficits (5.5%). There were differences in the correlates of the proportion of time each patient experienced symptoms of each domain. Depression, weeks of full time occupation and weeks on a disability pension were associated with both domains. Anxiety was associated only with diminished motivation. Lower performance IQ; extrapyramidal symptoms (EPS) and dysrhythmic EEG were associated only with proportion of time showing reduced expressiveness.

The prospective data support previous cross-sectional findings that, while these domains of negative symptoms are correlated, they do show differences in prevalence over time and in their correlates.