Comparison of psychotic bipolar disorder, schizoaffective disorder, and schizophrenia: an international, multisite study

OBJECTIVE

Nosological distinctions among schizoaffective disorder (SA), bipolar I disorder with psychotic features (BDp), and schizophrenia (SZ) remain unresolved.

METHOD

We compared 2269 subjects with psychotic features in DSM-IV-TR diagnoses (1435 BDp, 463 SZ, 371 SA) from 8 collaborating international sites, by 12 sociodemographic and clinical measures, all between diagnostic pairs.

RESULTS

In bivariate comparisons, SA was consistently intermediate between BDp and SZ for 11/12 features (except onset stressors), and SZ vs. BDp differed in all 12 factors. SA differed from both BDp and SZ in 9/12 factors: SA and BDp were similar in education and suicidal ideation or acts; SA and SZ were similar in education, onset stressors, and substance abuse. Meta-analytic comparisons of diagnostic pairs for 10 categorical factors indicated similar differences of SA from both SZ and BDp. Multivariate modeling indicated significantly independent differences between BDp and SZ (8 factors), SA vs. SZ (5), and BDp vs. SA (3). Measurement variance was similar for all diagnoses.

CONCLUSION

SA was consistently intermediate between BDp and SZ. The three diagnostic groups ranked: BDp > SA > SZ related to lesser morbidity or disability. The findings are not consistent with a dyadic Kraepelinian categorization, although the considerable overlap among the three DSM-IV diagnostic groups indicates uncertain boundaries if they represent distinct disorders.

Onset-age of bipolar disorders at six international sites

BACKGROUND

Onset-age is a stable characteristic of bipolar disorder (BPD) patients of clinical and probable psychobiological importance, but large pooled clinical samples from multiple sites employing modern diagnostic criteria to quantify onset-age remain rare.

METHODS

We pooled diagnostic, demographic, and clinical data from 1566 BPD patients from six international sites (5 European, 1 US) to compare onset-ages in subgroups.

RESULTS

Median+/-IQR onset in 1090 BP-I patients was 5.8 years younger than 476 BP-II cases (24.3+/-18.3 vs. 30.1+/-13.8 years; p<0.0001). Onset-age ranked: [a] BP-I men (23.0+/-12.8); [b] BP-I women (26.0+/-14.2); [c] BP-II men (29.7+/-19.1); and [d] BP-II women (30.1+/-17.5 years. Juvenile-onset (<or=age 20) was more common in Europe than the US (27% vs. 16%), as was childhood-onset (<13 years: 3.3% vs. 0%; both p<0.001). Proportion of all cases, and median onset for first episodes ranked: [a] BP-I psychotic (6.3%; 22.7+/-9.2); [b] BP-I manic (29.3%; 24.0+/-12.1); [c] BP-I depressed (25.1%; 24.5+/-14.9); [d] BP-I mixed (9.7%; 27.9+/-16.0); [e] BP-II depressed (26.9%; 30.0+/-19.5); and [f] BP-II hypomanic (2.8%; 33.6+/-15.1 years; p<0.0001). Among BP-I patients, onset was similar for various forms of mania and major depression; in BP-II patients initial depression was 9.6-times more frequent and diagnosed earlier than hypomania.

LIMITATIONS

There was some variance among sites and only 34.1% of patients were evaluated at onset.

CONCLUSIONS

Type I BPD began much earlier than type II; its mainly psychotic presentations occurred earliest, but BP-I men were younger than women, especially at psychotic or mixed onsets.