2 results
Fractal biomarker of activity in patients with bipolar disorder
- Stefan E. Knapen, Peng Li, Rixt F. Riemersma-van der Lek, Sanne Verkooijen, Marco P. M. Boks, Robert A. Schoevers, Frank A. J. L. Scheer, Kun Hu
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- Journal:
- Psychological Medicine / Volume 51 / Issue 9 / July 2021
- Published online by Cambridge University Press:
- 01 April 2020, pp. 1562-1569
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- Article
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Background
The output of many healthy physiological systems displays fractal fluctuations with self-similar temporal structures. Altered fractal patterns are associated with pathological conditions. There is evidence that patients with bipolar disorder have altered daily behaviors.
MethodsTo test whether fractal patterns in motor activity are altered in patients with bipolar disorder, we analyzed 2-week actigraphy data collected from 106 patients with bipolar disorder type I in a euthymic state, 73 unaffected siblings of patients, and 76 controls. To examine the link between fractal patterns and symptoms, we analyzed 180-day actigraphy and mood symptom data that were simultaneously collected from 14 patients.
ResultsCompared to controls, patients showed excessive regularity in motor activity fluctuations at small time scales (<1.5 h) as quantified by a larger scaling exponent (α1 > 1), indicating a more rigid motor control system. α1 values of siblings were between those of patients and controls. Further examinations revealed that the group differences in α1 were only significant in females. Sex also affected the group differences in fractal patterns at larger time scales (>2 h) as quantified by scaling exponent α2. Specifically, female patients and siblings had a smaller α2 compared to female controls, indicating more random activity fluctuations; while male patients had a larger α2 compared to male controls. Interestingly, a higher weekly depression score was associated with a lower α1 in the subsequent week.
ConclusionsOur results show sex- and scale-dependent alterations in fractal activity regulation in patients with bipolar disorder. The mechanisms underlying the alterations are yet to be determined.
The characteristics of psychotic features in bipolar disorder
- Annet H. van Bergen, Sanne Verkooijen, Annabel Vreeker, Lucija Abramovic, Manon H. Hillegers, Annet T. Spijker, Erik Hoencamp, Eline J. Regeer, Stefan E. Knapen, Rixt F. Riemersma-van der Lek, Robert Schoevers, Anja W. Stevens, Peter F.J Schulte, Ronald Vonk, Rocco Hoekstra, Nico J. van Beveren, Ralph W. Kupka, Iris E.C. Sommer, Roel A. Ophoff, René S. Kahn, Marco P.M. Boks
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- Journal:
- Psychological Medicine / Volume 49 / Issue 12 / September 2019
- Published online by Cambridge University Press:
- 10 October 2018, pp. 2036-2048
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Background
In a large and comprehensively assessed sample of patients with bipolar disorder type I (BDI), we investigated the prevalence of psychotic features and their relationship with life course, demographic, clinical, and cognitive characteristics. We hypothesized that groups of psychotic symptoms (Schneiderian, mood incongruent, thought disorder, delusions, and hallucinations) have distinct relations to risk factors.
MethodsIn a cross-sectional study of 1342 BDI patients, comprehensive demographical and clinical characteristics were assessed using the Structured Clinical Interview for DSM-IV (SCID-I) interview. In addition, levels of childhood maltreatment and intelligence quotient (IQ) were assessed. The relationships between these characteristics and psychotic symptoms were analyzed using multiple general linear models.
ResultsA lifetime history of psychotic symptoms was present in 73.8% of BDI patients and included delusions in 68.9% of patients and hallucinations in 42.6%. Patients with psychotic symptoms showed a significant younger age of disease onset (β = −0.09, t = −3.38, p = 0.001) and a higher number of hospitalizations for manic episodes (F11 338 = 56.53, p < 0.001). Total IQ was comparable between groups. Patients with hallucinations had significant higher levels of childhood maltreatment (β = 0.09, t = 3.04, p = 0.002).
ConclusionsIn this large cohort of BDI patients, the vast majority of patients had experienced psychotic symptoms. Psychotic symptoms in BDI were associated with an earlier disease onset and more frequent hospitalizations particularly for manic episodes. The study emphasizes the strength of the relation between childhood maltreatment and hallucinations but did not identify distinct subgroups based on psychotic features and instead reported of a large heterogeneity of psychotic symptoms in BD.