The British Journal of Psychiatry (2009) 195: 286-293. doi: 10.1192/bjp.bp.108.060723
© 2009 The Royal College of Psychiatrists
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Online supplement
Right arrow Submit an eLetter
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Related articles in BJP
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Scopus
Google Scholar
Right arrow Articles by Rajji, T. K.
Right arrow Articles by Mulsant, B. H.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Rajji, T. K.
Right arrow Articles by Mulsant, B. H.

REVIEW ARTICLE

Age at onset and cognition in schizophrenia: meta-analysis

T. K. Rajji, MD, FRCPC, Z. Ismail, MD, FRCPC and B. H. Mulsant, MD, MS, FRCPC

Department of Psychiatry, University of Toronto and Geriatric Mental Health Program, Centre for Addiction and Mental Health, Toronto, Canada

Correspondence: B. H. Mulsant, Geriatric Mental Health Program, CAMH, 1001 Queen Street West, Toronto, Ontario M6J 1H4, Canada. Email: Benoit_Mulsant{at}camh.net

Declaration of interest

None.

Background

The relationship between cognition and age at onset of schizophrenia is largely unknown.

Aims

To compare cognitive deficits in individuals with youth-onset and late-onset schizophrenia with those in adults with first-episode schizophrenia.

Method

Twenty-nine databases (including EMBASE, MEDLINE and PsycINFO) were searched from 1980 to 2008. Selected publications had to include healthy controls and analyse separately individuals diagnosed with schizophrenia or a related disorder and individuals with first-episode, youth-onset or late-onset schizophrenia. Descriptive and cognitive data were extracted and the latter aggregated into 22 cognitive measures. Cohen’s effect size raw and weighted means of cognitive deficits were generated and compared in the three groups.

Results

Individuals with youth-onset and first-episode schizophrenia demonstrate large deficits (mean effect size ≥0.8) on almost all cognitive measures. Individuals with youth-onset schizophrenia demonstrate larger deficits than those with first-episode schizophrenia on arithmetic, executive function, IQ, psychomotor speed of processing and verbal memory. In contrast, those with late-onset schizophrenia demonstrate minimal deficits on arithmetic, digit symbol coding and vocabulary, but larger ones on attention, fluency, global cognition, IQ and visuospatial construction.

Conclusions

Individuals with youth-onset schizophrenia have severe cognitive deficits, whereas those with late-onset schizophrenia have some relatively preserved cognitive functions. This finding supports the view that severity of the disease process is associated with different ages at onset. In addition, the cognitive pattern of people with late-onset schizophrenia suggests that their deficits are specific rather than solely as a result of ageing and related factors.


Related articles in BJP:

Highlights of this issue
Kimberlie Dean
BJP 2009 195: A12. [Full Text]