Solar insolation in springtime influences age of onset of bipolar I disorder

OBJECTIVE

To confirm prior findings that the larger the maximum monthly increase in solar insolation in springtime, the younger the age of onset of bipolar disorder.

METHOD

Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density.

RESULTS

There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001).

CONCLUSION

A large increase in springtime solar insolation may impact the onset of bipolar disorder, especially with a family history of mood disorders. Recent societal changes that affect light exposure (LED lighting, mobile devices backlit with LEDs) may influence adaptability to a springtime circadian challenge.

Recent advances in the understanding and management of bipolar disorder in adults

This article focuses on some aspects of recent progress in the neurobiology and treatment of bipolar disorder (BD) in adults. A molecular-genetic approach to the etiopathogenesis of the illness resulted in the findings of a genetic overlap between BD and other major psychiatric disorders. Furthermore, a poly-gene-environmental interaction in the development of the illness has been demonstrated. For the management of BD, new drugs with putative mood-stabilizing properties have been introduced in the past two decades. However, none of these can surpass lithium, the prototype mood-stabilizer, still considered the most specific drug for BD. Recent research on lithium, besides providing new data on the neurobiology of BD, has confirmed anti-suicidal, immunomodulatory, and neuroprotective properties of this drug.

Lipid Peroxidation and Immune Biomarkers Are Associated with Major Depression and Its Phenotypes, Including Treatment-Resistant Depression and Melancholia

To examine immune-inflammatory and oxidative (I&O) biomarkers in major depression (MDD) and its related phenotypes, we recruited 114 well-phenotyped depressed patients and 50 healthy controls and measured serum levels of interleukin (IL)-1α, soluble IL-1 receptor antagonist (sIL-1RA), soluble IL-2 receptor (sIL-2R), soluble IL-6 receptor (sIL-6R), soluble tumor necrosis factor receptor 60 and 80 kDa (sTNF-R1/R2), and thiobarbituric acid reactive substances (TBARS). Obtained results indicate that MDD is characterized by increased sIL-1RA, sTNF-R1, and TBARS concentrations. Melancholic depression is associated with increased sIL-6R but lowered IL-1α levels. A current episode of depression is accompanied by significantly increased sIL-6R compared to the remitted state. Treatment-resistant depression (TRD) is accompanied by increased sIL-6R and TBARS but lowered sTNF-R2 levels compared to non-TRD patients. These immune markers are not significantly correlated with Hamilton Depression Rating Scale (HDRS), Montgomery-Asberg Depression Scale (MADRS), number episodes, or age at onset. Our findings show that increased sIL-1RA, sTNF-R1, and TBARS levels may be trait markers of depression, while increased sIL-6R levels may be a state marker of melancholia and an acute phase of depression. MDD is accompanied by increased lipid peroxidation and simultaneous activation of immune pathways, and the compensatory anti-inflammatory reflex system (CIRS). TRD is characterized by highly increased oxidative stress and probably increased TNFα and IL-6 trans-signalling. Novel treatments for major depression should target oxidative stress pathways, while new treatments for TRD should primary target lipid peroxidation and also activated immune-inflammatory pathways.

International multi-site survey on the use of online support groups in bipolar disorder

BACKGROUND

Peer support is an established component of recovery from bipolar disorder, and online support groups may offer opportunities to expand the use of peer support at the patient's convenience. Prior research in bipolar disorder has reported value from online support groups.

AIMS

To understand the use of online support groups by patients with bipolar disorder as part of a larger project about information seeking.

METHODS

The results are based on a one-time, paper-based anonymous survey about information seeking by patients with bipolar disorder, which was translated into 12 languages. The survey was completed between March 2014 and January 2016 and included questions on the use of online support groups. All patients were diagnosed by a psychiatrist. Analysis included descriptive statistics and general estimating equations to account for correlated data.

RESULTS AND CONCLUSIONS

The survey was completed by 1222 patients in 17 countries. The patients used the Internet at a percentage similar to the general public. Of the Internet users who looked online for information about bipolar disorder, only 21.0% read or participated in support groups, chats, or forums for bipolar disorder (12.8% of the total sample). Given the benefits reported in prior research, clarification of the role of online support groups in bipolar disorder is needed. With only a minority of patients using online support groups, there are analytical challenges for future studies.

Ketamine augmentation rapidly improves depression scores in inpatients with treatment-resistant bipolar depression

OBJECTIVE

To study the clinical effect of a single ketamine infusion, 0.5 mg/kg body weight, in bipolar depressive patients receiving mood-stabilising drugs, not improving on antidepressants. Previously, in such patients, we had found a correlation between clinical efficacy, serum brain-derived neurotrophic factor and vitamin B12 levels and a rapid improvement in neurocognitive performance.

METHODS

The study included 53 patients (13 men, 40 women), aged 22-81 years, receiving ≥1 mood-stabilising medications of the first and/or second generation. Pre-infusion depression intensity on the Hamilton Depression Rating Scale (HDRS) was 23.4 ± 4.6 points and the assumed criterion for response was a reduction of ≥50% in the HDRS score after 7 days.

RESULTS

Twenty-seven subjects (51%) met a criterion for response, more frequently males (77%) than females (43%). Responders did not differ from non-responders as to age, illness onset, duration of depressive episode, type of bipolar illness, family history of psychiatric illness, personal/family history of alcoholism or using lithium, quetiapine or a combination of these mood stabilisers.

CONCLUSIONS

The results confirm a rapid antidepressant effect of ketamine infusion in a considerable proportion of those patients with bipolar depression receiving mood-stabilising drugs. Apart from male gender, no other clinical factors were predictors of response.

A Study of Biological Rhythm Disturbances in Polish Remitted Bipolar Patients using the BRIAN, CSM, and SWPAQ Scales

BACKGROUND/AIMS

The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) is a novel tool allowing for a complex assessment of biological rhythms. We compared patients with bipolar disorder (BD) and healthy control subjects (HC) using the Polish version of the BRIAN scale.

METHOD

Fifty-four remitted BD patients (17 males and 37 females aged 52 ± 13 years) and 54 healthy control subjects (25 males and 29 females aged 42 ± 14 years) were studied. In addition to the BRIAN scale, the Composite Scale of Morningness (CSM) and the Sleep-Wake Pattern Assessment Questionnaire (SWPAQ) were employed.

RESULTS

The Polish version of the BRIAN scale displayed high feasibility and consistency, showing that the patients had greater biological rhythm disturbances than the controls. After regression analysis, significant differences were obtained for the BRIAN subscales activity and predominant chronotype, and for the SWPAQ items quality of night-time sleep and ability to stay awake. We obtained positive correlations between higher BRIAN scores and morningness and eveningness, but the correlations with vigilance and the ability to stay awake (on the SWPAQ) were negative.

CONCLUSIONS

Using the BRIAN scale, we confirmed the greater disturbances of biological rhythm in Polish remitted bipolar patients, compared with healthy controls. The differences between these 2 groups in sleep-awake patterns were also demonstrated by the SWPAQ scores. In contrast to other studies, we were unable to confirm an evening chronotype as a discriminating factor between remitted bipolar patients and healthy subjects. This can be explained by the older age and the use of lithium by a significant proportion of the patients.

Increased affective empathy in bipolar patients during a manic episode

Objective:

To assess both cognitive and affective empathy in patients with bipolar disorder (BD) during an acute manic or depressive episode.

Methods:

The study included 25 patients with BD (aged 35±14 years) during an acute manic episode, 25 bipolar patients (aged 41±14 years) during a depressive episode, and 25 healthy control subjects (aged 36±11 years). Cognitive and affective empathy were assessed using the Multifaceted Empathy Test.

Results:

In both manic and depressive patients, a significant deficit in cognitive empathy was demonstrated. However, indices of affective empathy were significantly higher in the manic group than in depressed and control subjects. In the depressed patients, indices did not differ from those of healthy controls. For affective empathy, a significant positive correlation was found with intensity of manic symptoms and a negative correlation was found with intensity of depressive symptoms. No such correlations were observed with cognitive empathy.

Conclusion:

We found evidence of increased affective empathy (overempathizing) during a manic episode in bipolar patients. This phenomenon may be connected with disturbances in emotion inhibition related to anastrophic thinking and associated with increased activity of mirror neurons, all of which occur during a manic episode.

Administration of ketamine for unipolar and bipolar depression

OBJECTIVE

Clinical trials demonstrated that ketamine exhibits rapid antidepressant efficacy when administered in subanaesthetic dosages. We reviewed currently available literature investigating efficacy, response rates and safety profile.

METHODS

Twelve studies investigating unipolar, seven on bipolar depression were included after search in medline, scopus and web of science.

RESULTS

Randomized, placebo-controlled or open-label trials reported antidepressant response rates after 24 h on primary outcome measures at 61%. The average reduction of Hamilton Depression Rating Scale (HAM-D) was 10.9 points, Beck Depression Inventory (BDI) 15.7 points and Montgomery-Asberg Depression Rating Scale (MADRS) 20.8 points. Ketamine was always superior to placebo. Most common side effects were dizziness, blurred vision, restlessness, nausea/vomiting and headache, which were all reversible. Relapse rates ranged between 60% and 92%. To provide best practice-based information to patients, a consent-form for application and modification in local language is included.

CONCLUSIONS

Ketamine constitutes a novel, rapid and efficacious treatment option for patients suffering from treatment resistant depression and exhibits rapid and significant anti-suicidal effects. New administration routes might serve as alternative to intravenous regimes for potential usage in outpatient settings. However, long-term side effects are not known and short duration of antidepressant response need ways to prolong ketamine's efficacy.

The effect of long-term lithium treatment of bipolar disorder on stem cells circulating in peripheral blood

OBJECTIVES

To investigate the effect of long-term lithium treatment on very small embryonic-like stem cells (VSELs), haematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs) circulating in peripheral blood (PB), in bipolar disorder (BD).

METHODS

The study included 15 BD patients (aged 55 ± 6 years) treated with lithium for 8-40 years (mean 16 years), 15 BD patients (aged 53 ± 7 years) with duration of illness >10 years, who had never received lithium, and 15 healthy controls (aged 50 ± 5 years). The VSELs, HSCs, MSCs and EPCs were measured by flow cytometric analysis.

RESULTS

In BD subjects not taking lithium the number of CD34⁺VSELs was significantly higher, and MSCs and EPCs numerically higher, than in control subjects and the number of CD34⁺VSELs correlated with the duration of illness. In lithium-treated patients these values were similar to controls and the number of CD34⁺VSELs correlated negatively with the duration of lithium treatment and serum lithium concentration.

CONCLUSIONS

Long-term treatment with lithium may suppress the activation of regenerative processes by reducing the number of VSELs circulating in PB. These cells, in BD patients not treated with lithium, may provide a new potential biological marker of the illness and its clinical progress.

Atypical depression: current perspectives

The history and present status of the definition, prevalence, neurobiology, and treatment of atypical depression (AD) is presented. The concept of AD has evolved through the years, and currently, in Diagnostic and Statistical Manual of Mental Disorders (DSM), Fifth Edition, the specifier of depressive episode with atypical feature is present for both diagnostic groups, that is, depressive disorders and bipolar and related disorders. This specifier includes mood reactivity, hyperphagia, hypersomnia, leaden paralysis, and interpersonal rejection sensitivity. Prevalence rates of AD are variable, depending on the criteria, methodology, and settings. The results of epidemiological studies using DSM criteria suggest that 15%-29% of depressed patients have AD, and the results of clinical studies point to a prevalence of 18%-36%. A relationship of AD with bipolar depression, seasonal depression, and obesity has also been postulated. Pathogenic research has been mostly focused on distinguishing AD from melancholic depression. The differences have been found in biochemical studies in the areas of hypothalamic-pituitary-adrenal axis, inflammatory markers, and the leptin system, although the results obtained are frequently controversial. A number of findings concerning such differences have also been obtained using neuroimaging and neurophysiological and neuropsychological methods. An initial concept of AD as a preferentially monoamine oxidase inhibitor-responsive depression, although confirmed in some further studies, is of limited use nowadays. Currently, despite numerous drug trials, there are no comprehensive treatment guidelines for AD. We finalize the article by describing the future research perspectives for the definition, neurobiology, and treatment. A better specification of diagnostic criteria and description of clinical picture, a genome-wide association study of AD, and establishing updated treatment recommendations for this clinical phenomenon should be the priorities for the coming years.

Thiobarbituric Acid-Reactive Substances: Markers of an Acute Episode and a Late Stage of Bipolar Disorder

BACKGROUND

Lowered antioxidant defense systems and increased oxidative stress are implicated in bipolar disorders (BD). Early and late stages of BD may present different biological features (including the level of oxidative stress) and may therefore require different treatment strategies. The aim of this study was to analyze serum levels of lipid peroxidation [measured as thiobarbituric acid-reactive substances (TBARS), a derivative of malondialdehyde] in BD patients at various stages and phases of the illness and compare their TBARS levels with those of healthy controls.

METHOD

A total of 129 patients (58 in the depressive episode, 23 in the manic episode and 48 in remission) diagnosed with type I (n = 69) or type II (n = 60) BD and 50 healthy volunteers (control group) were enrolled in the study. The level of lipid peroxidation was measured in blood serum using a TBARS assay kit.

RESULTS

TBARS levels in the acute episode of mania/hypomania and depression (but not in remission) were significantly higher than in healthy controls. With regard to the BD stage, both early- and late-stage BD TBARS levels were significantly increased in patients in the depressive episode. In late-stage BD, the TBARS level in patients in remission remained elevated compared with controls. A multiple regression model confirmed the association between the TBARS level and BD stage or acute BD.

CONCLUSION

Our findings indicate that TBARS levels reflect the oxidative stress state which increases both in the acute phase of BD (mania/hypomania and depression) and with BD progression (stage).

Electroconvulsive therapy and cognitive functions in treatment-resistant depression

OBJECTIVES

Electroconvulsive therapy (ECT) is the most effective treatment for drug-resistant depression (DRD). We estimated the short- and long-term effects of ECT on cognitive functions in patients with unipolar and bipolar DRD.

METHODS

We investigated 63 patients (18 male, 45 female), aged 34-75 years. Cognitive assessments were performed before, immediately after 6-12 ECT sessions, and 3 months thereafter, using the Benton Visual Retention, Trail Making (TMT), Rey-Osterrieth Complex Figure (ROCF) tests, the Digit Span of the Wechsler Adult Intelligence Scale, and the Rey Auditory Verbal Learning (RAVLT), verbal fluency and Stroop tests.

RESULTS

Immediately after ECT, a significant worsening was noted in some indices of memory and verbal fluency. However, 3 months after ECT, the indices of both RAVLT and verbal fluency significantly improved compared to baseline, and those of the Benton and ROCF were significantly better than before ECT. The Digit Span, Stroop and TMT were not affected by the treatment.

CONCLUSIONS

The negative effects of ECT on the reported measures of cognition are transient. After 3 months, the indices of memory were significantly better than before the treatment. In addition to its antidepressant effect in DRD, ECT may also exert a long-term favourable influence on some cognitive functions.

The Biological Rhythms Interview of Assessment in Neuropsychiatry in patients with bipolar disorder: correlation with affective temperaments and schizotypy

Objective:

To assess the relationship of biological rhythms, evaluated by the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN), with affective temperaments and schizotypy.

Methods:

The BRIAN assessment, along with the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A) and the Oxford-Liverpool Inventory for Feelings and Experiences (O-LIFE), was administered to 54 patients with remitted bipolar disorder (BD) and 54 healthy control (HC) subjects.

Results:

The TEMPS-A cyclothymic temperament correlated positively and the hyperthymic temperament correlated negatively with BRIAN scores in both the BD and HC groups, although the correlation was stronger in BD subjects. Depressive temperament was associated with BRIAN scores in BD but not in HC; conversely, the irritable temperament was associated with BRIAN scores in HC, but not in BD. Several positive correlations between BRIAN scores and the schizotypal dimensions of the O-LIFE were observed in both BD and HC subjects, especially with cognitive disorganization and less so with unusual experiences and impulsive nonconformity. A correlation with introversion/anhedonia was found only in BD subjects.

Conclusion:

Cyclothymic and depressive temperaments predispose to disturbances of biological rhythms in BD, while a hyperthymic temperament can be protective. Similar predispositions were also found for all schizotypal dimensions, mostly for cognitive disorganization.

Increased mRNA expression of peripheral glial cell markers in bipolar disorder: The effect of long-term lithium treatment

Neuroinflammation, with microglial activation as an important element, plays a role in the pathogenesis of bipolar disorder (BD). Also, in mood disorders, pathological changes have been demonstrated in macroglial cells, such as astrocyctes and oligodendrocytes. Postmortem brain studies of BD patients to assess glial cells, such as astrocytes and oligodendrocytes and their markers such as glial fibrillary acidic protein (GFAP), Olig1 and Olig2, produced controversial results. On the other hand, investigation of these markers in the peripheral blood of such patients has not been performed so far. In this study, we examined the mRNA levels of GFAP, Olig1 and Olig2, in the peripheral blood of three groups: 15 BD subjects with a duration of illness at least 10 years (mean 20±9 years) but never treated with lithium, 15 subjects with BD treated continuously with lithium for 8-40 years (mean 16±8 years), and 15 control subjects. The groups were age-and sex-matched. Expression of mRNA markers was measured by real-time quantitative reverse transcription PCR (RQ-PCR). We observed increased mRNA levels of the Olig1 and Olig 2 glial markers studied in the BD patients not taking lithium, compared with the control subjects and increased mRNA level of GFAP, compared with lithium-treated patients. In the lithium-treated BD patients GFAP and Olig1 expression was at similar levels to that in the control group. However, Olig 2 expression was even higher than in the BD patients not taking lithium. The possible mechanisms concerning the higher expression of peripheral mRNA markers in BD patients may involve ongoing inflammatory process, compensatory mechanisms and regenerative responses. The beneficial effect of lithium may be related to its anti-inflammatory properties.

The assessment of orthorexia nervosa among 1899 Polish adolescents using the ORTO-15 questionnaire

OBJECTIVE

Orthorexia nervosa (ON) is considered an eating disorder (ED), with an excessive fixation on the consumption of healthy food and an obsession with its biological purity. Since the adolescent period poses a risk for EDs, the aim of this study was to assess the prevalence of ON in a population of Polish urban adolescents and some possible contributory factors.

METHOD

1899 high school students, 992 girls and 907 boys aged 15-21 years were studied. Demographic and clinical data were collected using a validated questionnaire including information on preferred living choices, in the context of pro- and antihealth activities. The Polish version of the ORTO-15 questionnaire was used.

RESULTS

The mean value of the ORTO-15 was 39.2 ± 3.6 points, with no sex difference. The main factors connected with orthorexia, according to the 'Orthorexia 33.35 and 40' definitions were excess weight, sporting activities, out-of-school activities, smoking status, working parents and a high family income.

CONCLUSIONS

This study, of a large number of adolescents, showed a prevalence of ON similar to that recorded in adult populations. Since factors predisposing to ON in adolescence differ from those for other eating disorders, it is not clear whether ON should be treated as a new form of ED.

Internet use by patients with bipolar disorder: Results from an international multisite survey

There is considerable international interest in online education of patients with bipolar disorder, yet little understanding of how patients use the Internet and other sources to seek information. 1171 patients with a diagnosis of bipolar disorder in 17 countries completed a paper-based, anonymous survey. 81% of the patients used the Internet, a percentage similar to the general public. Older age, less education, and challenges in country telecommunications infrastructure and demographics decreased the odds of using the Internet. About 78% of the Internet users looked online for information on bipolar disorder or 63% of the total sample. More years of education in relation to the country mean, and feeling very confident about managing life decreased the odds of seeking information on bipolar disorder online, while having attended support groups increased the odds. Patients who looked online for information on bipolar disorder consulted medical professionals plus a mean of 2.3 other information sources such as books, physician handouts, and others with bipolar disorder. Patients not using the Internet consulted medical professionals plus a mean of 1.6 other information sources. The percentage of patients with bipolar disorder who use the Internet is about the same as the general public. Other information sources remain important.

Kidney, thyroid and other organ functions after 40 years or more of lithium therapy: a case series of five patients

We present the cases of five patients (two men aged 64 years and 79 years) and three women (aged 64 years, 65 years and 75 years) who have received lithium treatment for 40-45 years, with particular regard to kidney and thyroid functions, hypercalcaemia and cognition, in the context of disease course and overall functioning. Lithium was initiated in the early phase of the illness (in three patients within the first 2 years). In four patients, lithium concentration was between 0.60 and 0.65 mmol/l and in one patient, between 0.7 and 0.8 mmol/l. Four were very good lithium responders. One man had stage 3 chronic kidney disease, and the other stage 2/3 chronic kidney disease. All three women had asymptomatic stage 2 chronic kidney disease. One woman had severe thyroid dysfunction (Hashimoto's disease) with extremely high levels of antithyroid peroxidase antibodies and antithyroglobulin antibodies and was receiving thyroxine. Serum calcium levels were normal or borderline in all five patients, and most cognitive functions were comparable to healthy persons of similar gender, age and years of education. All the patients were professionally active until 55-65 years and their family and social functioning were satisfactory. It was concluded that, in good lithium responders, ultra-long-term treatment with lithium enables good professional and psychosocial functioning, and the possible somatic side effects are manageable.

Genome-wide association study of 40,000 individuals identifies two novel loci associated with bipolar disorder

Bipolar disorder (BD) is a genetically complex mental illness characterized by severe oscillations of mood and behaviour. Genome-wide association studies (GWAS) have identified several risk loci that together account for a small portion of the heritability. To identify additional risk loci, we performed a two-stage meta-analysis of >9 million genetic variants in 9,784 bipolar disorder patients and 30,471 controls, the largest GWAS of BD to date. In this study, to increase power we used ∼2,000 lithium-treated cases with a long-term diagnosis of BD from the Consortium on Lithium Genetics, excess controls, and analytic methods optimized for markers on the X-chromosome. In addition to four known loci, results revealed genome-wide significant associations at two novel loci: an intergenic region on 9p21.3 (rs12553324, P =  5.87 × 10 -  9; odds ratio (OR) = 1.12) and markers within ERBB2 (rs2517959, P =  4.53 × 10 -  9; OR = 1.13). No significant X-chromosome associations were detected and X-linked markers explained very little BD heritability. The results add to a growing list of common autosomal variants involved in BD and illustrate the power of comparing well-characterized cases to an excess of controls in GWAS.

Renal sonography in bipolar patients on long-term lithium treatment

PURPOSE

The aim of the study was to analyze sonographic (US) renal findings in lithium-treated bipolar patients and to correlate them with renal function.

METHODS

Renal US and renal function tests were performed on 120 patients with bipolar disorder. Ninety patients (30 males, 60 females), aged 36-82 years, had received lithium therapy for an average of 16 years, whereas 30 patients (10 males, 20 females), aged 35-85 years, who had never been exposed to lithium, served as controls.

RESULTS

In the lithium-treated group, patients with macrocysts (22%) had poorer renal function with higher creatinine serum concentrations, lower estimated glomerular filtration rates, and lower urine specific gravity, compared with the patients without macrocysts. The US changes characteristic for lithium nephropathy (punctate hyperechoic foci, microcysts < 2 mm, and increased echogenicity) were seen in three patients. These patients had been treated with lithium for more than 20 years and had impaired renal function. Sixteen percent of patients in the control group had macrocysts; however, no correlation between their presence and impaired renal function was found.

CONCLUSIONS

The presence of macrocysts in the kidneys of lithium-treated bipolar patients is associated with impaired renal function. The US changes characteristic for lithium nephropathy are rare, and in our study, were only found in patients treated with lithium for 20 years or more. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:354-359, 2016.

Genetic variants associated with response to lithium treatment in bipolar disorder: a genome-wide association study

BACKGROUND

Lithium is a first-line treatment in bipolar disorder, but individual response is variable. Previous studies have suggested that lithium response is a heritable trait. However, no genetic markers of treatment response have been reproducibly identified.

METHODS

Here, we report the results of a genome-wide association study of lithium response in 2563 patients collected by 22 participating sites from the International Consortium on Lithium Genetics (ConLiGen). Data from common single nucleotide polymorphisms (SNPs) were tested for association with categorical and continuous ratings of lithium response. Lithium response was measured using a well established scale (Alda scale). Genotyped SNPs were used to generate data at more than 6 million sites, using standard genomic imputation methods. Traits were regressed against genotype dosage. Results were combined across two batches by meta-analysis.

FINDINGS

A single locus of four linked SNPs on chromosome 21 met genome-wide significance criteria for association with lithium response (rs79663003, p=1·37 × 10(-8); rs78015114, p=1·31 × 10(-8); rs74795342, p=3·31 × 10(-9); and rs75222709, p=3·50 × 10(-9)). In an independent, prospective study of 73 patients treated with lithium monotherapy for a period of up to 2 years, carriers of the response-associated alleles had a significantly lower rate of relapse than carriers of the alternate alleles (p=0·03268, hazard ratio 3·8, 95% CI 1·1-13·0).

INTERPRETATION

The response-associated region contains two genes for long, non-coding RNAs (lncRNAs), AL157359.3 and AL157359.4. LncRNAs are increasingly appreciated as important regulators of gene expression, particularly in the CNS. Confirmed biomarkers of lithium response would constitute an important step forward in the clinical management of bipolar disorder. Further studies are needed to establish the biological context and potential clinical utility of these findings.

FUNDING

Deutsche Forschungsgemeinschaft, National Institute of Mental Health Intramural Research Program.