Preceding Diagnoses to Young Adult BD and Schizophrenia
Preceding Diagnoses to Young Adult BD and Schizophrenia
A flow-chart of the identification of the patients in the present study is provided in Figure 1. There were significantly different sex distributions in the samples with more females in the BD sample (N = 484 [61.7%] females vs. N = 300 [38.3%] males) (Chi2 = 43.2, df = 1; p = <0.001) and significantly more males in the SZ sample (N = 1.073 [64.4%] males vs. N = 594 [35.6%] females) (Chi2 = 137.6, df = 1; p = <0.001). The mean age at diagnosis of BD was 27.8 (SD = 4.0) years and it was 26.3 (SD = 4.1) years in the SZ sample. Age at first time diagnosis differed significantly between patients diagnosed with BD or SZ (Z = -8.6; p < 0.001).
(Enlarge Image)
Figure 1.
Flowchart.
In the two cohorts, N = 543 (69.3%) patients diagnosed with BD and N = 1,277 (76.6%) patients diagnosed with SZ had a preceding diagnosis. Lifetime preceding psychiatric disorders and preceding psychiatric disorders with onset in childhood and adolescence are shown in Table 1. Lifetime prevalence rates were high for preceding SUD (26.9%) and psychoses (41.5%) in SZ and for preceding affective disorders (46.6%) in BD. All prevalence rates of preceding disorders including ADHD and CD in particular were low during childhood and adolescence in both samples.
As seen in the lifetime frequencies in Table 1, preceding SUD in particular, due to cannabis use disorders, psychoses, schizoid and antisocial personality disorders, and CD were observed significantly more in SZ patients. Affective disorders and, in particular, mania and depressive disorders were significantly more frequent in BD patients. However, there was little differentiation of the two samples in terms of preceding disorders originating in childhood and adolescence. Only cannabis use disorder was significantly more common in SZ than in BD in this period.
Comparisons of the age of first time diagnosis of the preceding disorder for the major groups of disorders are shown in Table 2. The findings indicate that SZ was associated with a significantly earlier onset of preceding affective disorders, reactions to severe stress, and personality disorders.
The results of the effect of birth year and sex on the risk of having the various preceding diagnoses are presented in Table 3, and the effect of the various comorbid disorders on the risk of BD/SZ is presented in Table 4. Male sex was a risk factor for SUD, psychosis and ADHD, while female sex was a risk factor for affective disorders, anxiety disorders, reactions to severe stress and personality disorders. There were significant effects on the risk of the preceding disorders associated with year of birth with persons born after 1980 having an elevated risk of being diagnosed with all psychiatric disorders. Most pronounced was the effect for ADHD and conduct disorder when controlling for length of follow-up time (Table 3). The adjusted models showed that ADHD was weakly associated with an increased risk for BD compared to SZ (Table 4). Preceding affective disorders were strongly associated with BD whereas SUD, psychoses, anxiety disorders and personality disorders increased the risk of SZ compared to BD. No differences were found for risk of diagnosis of BD compared to SZ for reactions to severe stress and conduct disorder.
Results
A flow-chart of the identification of the patients in the present study is provided in Figure 1. There were significantly different sex distributions in the samples with more females in the BD sample (N = 484 [61.7%] females vs. N = 300 [38.3%] males) (Chi2 = 43.2, df = 1; p = <0.001) and significantly more males in the SZ sample (N = 1.073 [64.4%] males vs. N = 594 [35.6%] females) (Chi2 = 137.6, df = 1; p = <0.001). The mean age at diagnosis of BD was 27.8 (SD = 4.0) years and it was 26.3 (SD = 4.1) years in the SZ sample. Age at first time diagnosis differed significantly between patients diagnosed with BD or SZ (Z = -8.6; p < 0.001).
(Enlarge Image)
Figure 1.
Flowchart.
In the two cohorts, N = 543 (69.3%) patients diagnosed with BD and N = 1,277 (76.6%) patients diagnosed with SZ had a preceding diagnosis. Lifetime preceding psychiatric disorders and preceding psychiatric disorders with onset in childhood and adolescence are shown in Table 1. Lifetime prevalence rates were high for preceding SUD (26.9%) and psychoses (41.5%) in SZ and for preceding affective disorders (46.6%) in BD. All prevalence rates of preceding disorders including ADHD and CD in particular were low during childhood and adolescence in both samples.
As seen in the lifetime frequencies in Table 1, preceding SUD in particular, due to cannabis use disorders, psychoses, schizoid and antisocial personality disorders, and CD were observed significantly more in SZ patients. Affective disorders and, in particular, mania and depressive disorders were significantly more frequent in BD patients. However, there was little differentiation of the two samples in terms of preceding disorders originating in childhood and adolescence. Only cannabis use disorder was significantly more common in SZ than in BD in this period.
Comparisons of the age of first time diagnosis of the preceding disorder for the major groups of disorders are shown in Table 2. The findings indicate that SZ was associated with a significantly earlier onset of preceding affective disorders, reactions to severe stress, and personality disorders.
The results of the effect of birth year and sex on the risk of having the various preceding diagnoses are presented in Table 3, and the effect of the various comorbid disorders on the risk of BD/SZ is presented in Table 4. Male sex was a risk factor for SUD, psychosis and ADHD, while female sex was a risk factor for affective disorders, anxiety disorders, reactions to severe stress and personality disorders. There were significant effects on the risk of the preceding disorders associated with year of birth with persons born after 1980 having an elevated risk of being diagnosed with all psychiatric disorders. Most pronounced was the effect for ADHD and conduct disorder when controlling for length of follow-up time (Table 3). The adjusted models showed that ADHD was weakly associated with an increased risk for BD compared to SZ (Table 4). Preceding affective disorders were strongly associated with BD whereas SUD, psychoses, anxiety disorders and personality disorders increased the risk of SZ compared to BD. No differences were found for risk of diagnosis of BD compared to SZ for reactions to severe stress and conduct disorder.
