background Longer duration of untreated psychosis (dup) is often associated with poorer outcome, in terms of positive symptoms, increased chance of relapse, and longer time till remission. In contrast, the association with negative symptoms has been less consistently substantiated.
aim To determine the relationship between dup and negative symptoms during a follow-up period of up to eight years.
method Relevant databases were searched for studies published before March 2009 which reported data on dup and negative symptoms. Using individual patient data, we calculated, for each study, correlations at baseline, at the end of a short follow-up and at the end of a long follow-up period. We performed a meta-analysis involving regression analysis to ascertain the nature (i.e. the linearity) of the relationship between dup and the course of negative symptoms.
results We extracted 28 non-overlapping studies from 402 relevant papers located via the databases we had consulted. We were able to collect individual patient data from 16 studies (n = 3339). The average dup was 61.4 weeks (sd: 132.7, median: 12.0). Shorter dup was significantly associated with less severe negative symptoms at all follow-up assessments. The relationship between the course of negative symptoms and dup was found to be non-linear and weakened markedly when dup was longer than nine months.
conclusion Shorter dup is associated with less severe negative symptoms at follow-up assessments, the first nine months being the most critical period. Since there is no effective treatment for negative symptoms and dup was found to be non-linear, reducing dup seems to be an important way of shortening the duration of negative symptoms.