Discuss Bipolar
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Variations in the D-amino acid oxidase activator gene (DAOA) are linked to the development of bipolar disorder and schizophrenia, although they account for only a part of genetic susceptibility, UK study findings suggest.
Previous studies have associated the DAOA/G30 locus or the neighboring region of chromosome 13q33.2 with both bipolar disorder and schizophrenia, while four single nucleotide polymorphisms (SNPs) at 12q24.11 have been linked to schizophrenia. However, the results have been conflicting.
Hugh Gurling, from University College London, and colleagues therefore genotyped 431 schizophrenia patients, 303 bipolar disorder patients, and 442 ancestrally matched controls with no history of mental disorder.
All participants were genotyped for 11 SNPs at the DAOA locus, with schizophrenia patients and controls also genotyped for three SNPs at the D-amino acid oxidase gene (DAO) locus on chromosome 12.
The results, published in the journal Behavioral and Brain Functions, reveal that the SNP rs3918342 (M23) at the DAOA locus was significantly associated with schizophrenia, bipolar disorder, and both conditions combined.
There was a trend toward association with schizophrenia for the SNPs rs3916967 (M14) and rs1421292 (M24), with the latter also marginally significantly associated with both conditions combined.
The team also found that there was a haplotypic association with schizophrenia for the markers rs778293 (M22), rs3918342 (M23), and rs1421292 (M42), with alleles G, T, A increasing the risk for schizophrenia at an estimated frequency of 1.8% in controls and 3.6% in patients. None of the three DOA SNPs were associated with schizophrenia.
The team concludes: “Our findings point to a role for DAOA in both schizophrenia and bipolar disorder. However, it is evident that this locus can account for only a small proportion of genetic susceptibility to these disorders.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
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Criminal behavior and violent crimes among patients with affective disorder are associated with more than just overall diagnosis, say German scientists who found a range of factors linked to such behavior.
There has been a great deal of research into criminal and violent behavior in schizophrenia patients. In contrast, there have been few studies of violent and criminal behavior in individuals with affective disorders, and those that have been conducted have, in the main, not differentiated between bipolar disorder, mania, and depression.
To investigate further, Michael Soyka, from Ludwig-Maximilian-University in Munich, and colleagues examined data from the German national crime register of criminal offenses for nonviolent and violent behavior committed by 1561 affective disorder patients, of whom 756 had bipolar disorder, 89 manic disorder, and 702 major depressive disorder (MDD).
The average age of the patients was 53.26 years. In all, 2.1% were single, 47.9% were married or living with a partner, 18.8% were separated or divorced, and 11.2% were widowed. The average hospital stay was 64.39 days. Lack of insight at discharge was observed in just 1.4% of patients. In addition, 21.1% of patients reported a history of substance use problems.
Overall, 95.8% of patients had no conviction after discharge, at 84.3% of manic disorder patients, 97.8% of bipolar disorder patients, and 95.3% of MDD patients, the team notes in the Journal of Affective Disorders. Sixty five patients committed criminal acts, at an average of 4.72 per patient. Defalcation, theft, and fraud were the most common crimes, while physical assault was the most common violent behavior. There was one murder.
Among patients who committed criminal and violent behavior, men were substantially more likely to commit both criminal and violent behavior after discharge than women, at 64.6% versus 35.4% and 85.7% versus 14.3%, respectively. The gender differences were even greater among manic patients (78.6% vs 21.4% and 100.0% vs 0.0%, respectively) and among those with MDD (60.6% vs 39.4% and 90.0% vs 10.0%, respectively).
Separated, divorced, and widowed patients committed offenses more frequently than other individuals. There was no association with age, educational status, length of hospital stay, lack of insight at diagnosis, or history of substance abuse.
The team concludes: “The findings of this study may stimulate further research to identify social and psychopathological predictors for future violent and criminal behavior.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
Using diffusion tensor imaging (DTI), researchers have found evidence of microstructural white matter modifications in euthymic bipolar patients suggestive of increases in white matter axonal organization.
Bipolar disorder has been associated with macrostructural white matter abnormalities, observed as changes in fractional anisotropy (FA) and mean diffusivity (MD) when measuring the integrity of white matter tracts using DTI.
Michèle Wessa (Central Institute of Mental Health, Mannheim, Germany) and colleagues say that, so far, DTI studies in bipolar patients have focused on frontal/prefrontal brain regions only.
To investigate further, the researchers performed DTI with diffusion gradients applied along 41 directions in 22 bipolar I and II disorder patients in remission, with no lifetime or present comorbidities of substance abuse, and 21 gender- and age-matched healthy controls with no history of mental illness.
The study showed an increase of functional anisotropy (FA) in medial frontal, precentral, inferior parietal, and occipital cortical areas in euthymic bipolar patients compared with healthy individuals, with no changes in mean diffusivity seen between the groups.
FA and MD did not correlatie with duration of illness or number of episodes, andpatients did not differ in FA measurements with respect to medication type.
The researchers say that an increase in FA without modification in MD most likely reflects an “increase in the directional coherence and thus axonal organization of the [white matter] fibers rather than increases in axonal myelination,” as FA is rendered an estimate of white matter bundle integrity.
However, previous DTI studies have reported decreased FA in bipolar patients in prefrontal, callosal, and occipital white matter. Wessa and team suggest that this discrepancy may be the result of previous studies using patients in various mood states and with a previous history of subst