Lead-Time Bias as a Potential Explanation for the Link Between Duration of Untreated Psychosis and Outcome: Response to Iyer et al

Pre-onset subthreshold psychotic symptoms are associated with differential treatment delays before a first episode of psychosis: Initial evidence and implications

BACKGROUND

Help-seeking and treatment delays are increasingly critical areas of study in mental health services. The duration of untreated psychosis (DUP), or the time between illness onset and initiation of treatment, is a predictor of symptom remission and functioning for a first episode of psychosis (FEP). The World Health Organization recommends that specialized treatment for psychosis be initiated within the first three months of FEP onset. As a result, research has focused on factors that are associated with threshold-level DUP, while the experience of subthreshold psychotic symptoms (STPS) prior to a FEP may also complicate and present barriers to accessing care for young people. We therefore examine the possibility that STPS can impact DUP and its components.

METHOD

Using a follow-back cross-sectional design, we sought to describe duration of untreated illness, length of prodrome, DUP, help-seeking delay, referral delay, and number of help-seeking contacts among FEP patients who did and did not have STPS prior to psychosis onset.

RESULTS

We found that patients who experienced STPS had a longer median duration of untreated illness, prodrome length, DUP, and help-seeking delay compared to patients who did not have such symptoms. Referral delay did not differ substantially between the two groups. Importantly, treatment delays were extremely lengthy for many participants.

CONCLUSIONS

Pre-onset STPS are associated with help-seeking delays along the pathway to care even during a FEP. Examining early signs and symptoms may help to improve and tailor interventions aimed at reducing treatment delays and ultimately providing timely care when the need arises.

Functioning pre- and post-treatment in schizophrenia; further investigations into lead time bias and duration of untreated psychosis

OBJECTIVE

The association between duration of untreated psychosis (DUP) and later outcome is not fully understood. Jonas et al. in their 20-year follow-up found that the association could be explained by lead-time bias. In this study we aimed to analyze the relationship between DUP, time since onset of psychosis and functional outcome using a similar statistical approach as the Jonas study.

METHOD

Using data from 496 participants with first-episode schizophrenia, DUP was assessed using the IRAOS and functioning at the baseline assessment and the subsequent follow-ups (1, 2, 5 and 10 years) was assessed using the GAF-F. For premorbid functioning, the Premorbid Assessment of Functioning Scale was used and rescaled to correspond to the GAF.

RESULTS

The model with the best fit of data included both a slope and a level change. This model of level of function over time had the inflection point at the time of first treatment. This model indicated a slow decline per year until first treatment, at which point there was a sharp decrease in functioning, and after which functioning gradually improved again. Both in this model and in models accounting for potential lead-time bias, however, longer DUP was associated with a decrease in function for each additional week of DUP. This is in contrast with the Jonas et al. study.

CONCLUSION

In this study, we did not find evidence of a lead-time bias, but rather found that onset of treatment occurs at the time when participants level of functioning was most impaired, and consequently was not at random.