Duration of untreated prodromal symptoms in individuals at clinical high risk for psychosis; analysis of onset of prodromal symptoms, and the effect of duration on outcomes in clinical high-risk populations.

Introduction: It is believed that people affected by schizophrenia, who have a long gap between the onset of psychotic symptoms, and the start of treatment have worse outcomes, both in the short and long-term. This is called the duration of untreated psychosis hypothesis An area where there is limited current research is the effect of the duration of prodromal symptoms in people at clinical high risk for psychosis (CHR-P). These prodromal symptoms are reported in a majority of those who transition to psychosis, suggesting that they may be significant for later outcomes. This study focuses on the timing of the relative onset of attenuated psychotic symptoms (APS) and basic symptoms (BS); on the reported duration of BS and APS, from participants at CHR-P; and the effects of these on functional outcomes, and on cognition. There is a specific hypothesis that APS are a consequence of BS, implying that BS should commence before APS. Methods: Participants were recruited as part of the Youth mental health, risk and Resilience (YouR) study. This is a community-based study, carried out among people aged 16 to 35 in Glasgow and Edinburgh, analyzing emerging psychotic symptoms. Data from 134 CHR-P participants were analyzed for the duration of APS and BS and these were related to global assessment of functioning (GAF), role functioning and social functioning. Two measures of cognition were collected during baseline assessments. An analysis was conducted to compare duration of APS and BS symptoms, and to assess the effect of duration on GAF scores, role functioning, social functioning and cognition measures. Results: There was no significant relationship between BS onset and APS, and in a significant percentage of the sample (n = 24, 37.5%) the reported APS onset was prior to BS onset. Only CHR-P individuals with long BS showed some evidence for the hypothesized relationship of BS preceding APS (n = 13, p = 0.04). Duration of APS and BS showed no significant effects on cognition, except for small effects on motor speed and verbal fluency. Duration of prodromal symptoms also did not show any significant effects on any of the measures of functioning. Discussion: The current study did not support the hypothesis that BS precedes the emergence of APS in individuals who are CHR-P. This could have significant implications for current conceptions of APS and BS in the prodromal period. A number of factors have been previously reported to effect recall of duration of prodromal symptoms, including years of education and age at onset of symptoms. No evidence was found of between group differences. These findings produce two key questions; how accurate is the hypothesis that APS are a secondary consequence of BS, and are there between group differences previously not considered which may affect the difference in reported symptoms. Areas for future research on this topic are discussed. The implications of the negative findings for functioning and cognition are compared to current research into duration of untreated psychosis. The differences in the finding are theorized to be linked to two key hypotheses in psychosis; the critical period of psychosis and the neurodevelopmental theory of psychosis. Both these theories have time dependent components, but current research using duration of prodromal symptoms is limited. Potential implications of this study as preliminary evidence for them are discussed. Finally, this study reported significantly longer duration of prodromal symptoms in a non-help seeking sample, compared to previous findings conducted on clinical samples. The implications of these findings and suggestion for future research are discussed