What is the average age of onset for bipolar

Gaussian probability density function was derived by the estimated age at onset mixture function in the whole sample of bipolar disorder patients. Further, they also had a lower age at interview and longer illness duration than LO BD2. Multivariate analysis was not performed in BD1 since no clinical variable was significantly associated with AAO subgroup in univariate test.

The results of the univariate analysis are shown in Table 3. Conversely, EO BD2 had a higher rate of comorbidity with alcohol dependence. The present study highlighted that a two normal component model in BD1 as well as in BD2 diagnostic subgroup best described the distribution of AAO. This finding was not reflected, however, in similar distributional properties of AAO, as well as in comparable pattern of association with clinical variables between the two diagnostic subgroups.

The bimodal AAO distribution found in both BD diagnostic subgroups and in the whole sample of patients is consistent with some studies Ortiz et al. Conversely, the majority of studies on mixture analysis of AAO showed a trimodal distribution in samples comprising mainly BD1 patients Bellivier et al.

Further research is needed to determine which distribution bi- or tri-modal better describes AAO in BD and which is or which are the best cut-off s before investigating clinical correlates and genetic differences between subgroups based on AAO.

In fact, thresholds between subgroups found in different studies differed [e. Discrepancies in the identified AAO distributions, cut-off points, and proportions of patients in each AAO subgroups may depend on diverse assessment methods, recall bias, study design Montlahuc et al. Concerning study design, Montlahuc et al.

Importantly, a combination of left and right truncation, which is common in previously published studies of AAO admixture analysis, appeared to significantly influence the number of AAO subgroups detected Montlahuc et al. Geographical location appears also to impact on AAO admixture analysis findings. Bellivier et al. Finally, birth cohort effect might also influence the estimation of AAO subgroups parameters.

In this regard, Golmard et al. Several other findings deserve a comment. Similarly, previous studies investigating clinical correlates of AAO subgroups found that EO BD patients have higher rates of alcohol abuse Javaid et al. However, these studies either analysed only BD1 individuals Lin et al.

Interestingly, a recent study from Propper et al. Although not directly comparable with our study, the findings reported by Perlis et al. In addition, our findings were consistent with the work of Koukopoulos et al.

Differently from what reported in the literature, our study failed to confirm in the BD1 subgroup the well-established association of EO BD with a higher familial load for BD and for mood disorders in general, as well as with higher rates of suicidal behaviour Geoffroy et al. Similarly, Baek et al. There is compelling evidence that EO BD patients appear also to be more frequently associated with rapid cycling, drug abuse, higher rates of obsessive—compulsive disorder, and possibly for psychotic features, and panic disorder Geoffroy et al.

Although our study did not test for association most of these clinical correlates, there were no statistically significant associations with EO for drug dependence. Our results should be interpreted in the context of some limitations.

The retrospective assessment of AAO might have been subject to recall bias. However, data were gathered through direct interview of the patients as well as with systematic review of medical charts decreasing the probability of a systematic bias in the assessment of AAO. An additional limitation is the lack of a systematic approach in collecting family history data, which might have influenced the assessment of familial load in our sample.

Moreover, external corroboration for AAO was obtained, whenever possible, by directly interviewing a first-degree family member or other significant individuals. Further, our samples of BD1 and BD2 patients might not have had an adequate statistical power to detect association signals of small to moderate magnitude.

Finally, our study did not consider birth cohort effect in our analysis. Should our findings be replicated in other studies directly comparing AAO BD1 subgroups with AAO BD2 subgroups, future work will be able to focus also on the differences in the genetic and biological makeup, possibly facilitating the search for reliable disease biomarkers.

Alda M. The phenotypic spectra of bipolar disorder. Eur Neuropsychopharmacol. Investigating responders to lithium prophylaxis as a strategy for mapping susceptibility genes for bipolar disorder. Prog Neuropsychopharmacol Biol Psychiatry. American Psychiatric Association. Diagnostic and statistical manual of mental disorders 4th ed. Google Scholar. Differences between bipolar I and bipolar II disorders in clinical features, comorbidity, and family history.

J Affect Disord. Article PubMed Google Scholar. Influence of birth cohort on age of onset cluster analysis in bipolar I disorder. Eur Psychiatry. World J Biol Psychiatry. Admixture analysis of age at onset in bipolar I affective disorder.

Arch Gen Psychiatry. Age at onset in bipolar I affective disorder: further evidence for three subgroups. Am J Psychiatry. Genome-wide association analysis of age at onset and psychotic symptoms in bipolar disorder. Article Google Scholar. J Stat Softw. Italian bipolar II vs I patients have better individual functioning, in spite of overall similar illness severity. CNS Spectr ;1—8. A SNAP25 promoter variant is associated with early-onset bipolar disorder and a high expression level in brain.

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