Refining criteria for a neurodevelopmental sub-phenotype of bipolar disorders: a FondaMental Advanced Centers of Expertise for Bipolar Disorders study.

BACKGROUND: Bipolar disorder (BD) is a complex and heterogeneous psychiatric disorder. Neurodevelopmental factors were suggested to contribute to the etiology of BD, yet a specific neurodevelopmental phenotype of the disorder remains unidentified. Our objective was to define and characterize a neurodevelopmental phenotype (NDP) in BD and validate its associations with clinical outcomes, polygenic risk scores (PGS), and treatment responses. METHOD: We analyzed the FACE-BD cohort of 4,468 BD patients, a validation cohort of 101 BD patients, and two independent replication datasets of 274 and 89 BD patients. Using factor analyses, we identified a set of criteria for defining NDP. We next developed a scoring system for NDP-load and assessed its association with prognosis, neurological soft signs, polygenic risk scores for neurodevelopmental disorders, and responses to treatment using multiple regressions, adjusted for age and sex with bootstrap replications. RESULTS: Our study established a NDP in BD consisting of nine clinical features: advanced paternal age, advanced maternal age, childhood maltreatment, attention deficit hyperactivity disorder (ADHD), early onset of BD, early onset of substance use disorders, early onset of anxiety disorders, early onset of eating disorders, specific learning disorders. Patients with higher NDP-load showed a worse prognosis and increased neurological soft signs. Notably, these individuals exhibited a poorer response to lithium treatment. Furthermore, a significant positive correlation was observed between the NDP-load and PGS for ADHD suggesting potential overlapping genetic factors or pathophysiological mechanisms between BD and ADHD. CONCLUSIONS: The proposed NDP constitutes a promising clinical tool for patient stratification in BD.

Positive psychological functioning, resilience and styles of coping as buffers against suicidal behaviours. A case-control study.

BACKGROUND: Studies in the literature mainly focus on understanding the risk factors for suicide, giving little relevance to protective variables. This study aimed at exploring the specific contribution of protective variables (resilience, coping and psychological well-being) in hospitalized suicide attempt (SA) makers. METHODS: We recruited 50 inpatients who made a SA before admission and 50 inpatients with no history of SA matched for DSM-5 diagnosis, gender and age. Protective variables were evaluated with: Brief COPE questionnaire, Dispositional Resilience Scale (DRS-15), Psychological Well-Being Scale (PWB-18). Psychopathological features and symptom severity were assessed with: Global Assessment of Functioning Scale (GAF), Rapid Dimensional Assessment Scale (SVARAD), Brief Psychiatric Rating Scale (BPRS), Clinical Global Impressions (CGI), Hamilton Depression Rating Scale (HDRS17). RESULTS: The DRS-15 total score was significantly lower in SA makers. SA makers displayed significantly lower scores on the Engagement and Cognitive Restructuring subscales of the Brief COPE. On the PWB-18, the Self-Acceptance subscale score was lower in SA makers. LIMITATIONS: The small sample size suggests the need for caution in interpreting the results. Matching was carried out by excluding diagnoses of personality disorders. CONCLUSIONS: Patients hospitalized following a SA are more often diagnosed with personality disorders, have deficit areas concerning resilience and coping, and lower psychological well-being compared to patients without a SA. When approaching a patient who has committed a SA, it may be useful to evaluate protective variables as well as risk factors, and encourage the development of adaptive coping mechanisms and positive self-evaluation through more dynamic therapeutic paths.

Antidepressant-associated diagnostic change from major depressive to bipolar disorder.

BACKGROUND: Anticipating diagnostic change from major depressive (MDD) to bipolar disorder (BD) can support better prognosis and treatment, especially of depression but is challenging and reported research results are inconsistent. We therefore assessed clinical characteristics associated with diagnostic change from MDD to BD with antidepressant treatments. METHODS: We compared characteristics of 3212 initially MDD patients who became (hypo)manic during antidepressant treatment to those with stable MDD diagnoses as well as with cases of stable, spontaneous BD, using standard bivariate and multivariate statistics. RESULTS: Among MDD patients, 6.69% [CI: 5.85-7.61] changed to BD, mostly type II (BD2, 76.7%). BD-converters had higher rates of familial mood disorders (74.1% vs. 57.1%) or BD (33.7% vs. 21.0%) and 2.8-years younger onset than stable MDD patients. They also had more prior depressive recurrences/year, years-of-illness, mood-stabilizer treatment, divorces, fewer children, more suicide attempts and drug-abuse, and higher intake cyclothymia, YMRS and MDQ scores. Predictors independently associated with diagnostic conversion were: more familial BD, depressions/year, unemployment, cyclothymic temperament, suicidal ideation or acts, and fewer children. BD-converters vs. spontaneous BD cases had significantly more suicide attempts, BD2 diagnoses, and affected relatives. Converting to vs. spontaneous BD1 was associated with more ADHD, more suicidal ideation or behavior, MDI course, and younger onset; converting to vs. spontaneous BD2 had more episodes/year, unemployment, ADHD, substance abuse, suicidal ideation or attempts, and more relatives with BD. CONCLUSIONS: Few (6.69%) initially MDD subjects converted to BD, most (76.7%) to BD2. Independent predictive associations with diagnostic change included: familial BD, more depressions/year, unemployment, cyclothymic temperament, suicidal behavior and fewer children. Notably, several characteristics were stronger among those changing to BD during antidepressant treatment vs. others with spontaneous BD.

Lithium-discontinuation-induced treatment refractoriness revisited.

BACKGROUND: Lithium is effective in the long-term treatment of bipolar disorder. Concerns have been raised about non-responsiveness after discontinuation and resuming previously effective lithium prophylaxis. We reviewed the available literature on this so-called lithium-discontinuation-induced treatment refractoriness (LDITR). RESULTS: We found 11 case reports and six cohort studies including 403 patients addressing LDITR, and one nation-wide register study providing some additional data on LDITR. Pooling all cohort studies, the percentages of non-responders during re-treatment with lithium ranged from 3.6 to 27.7%, with an average of 17.3%. Non-responsiveness was associated with longer duration of lithium treatment before discontinuation, longer duration of bipolar disorder before start of lithium, faster tapering off lithium, and longer duration of discontinuation. CONCLUSIONS: There may be a subgroup in whom lithium discontinuation-induced treatment refractoriness exists. However, the vast majority of people respond when lithium is restarted. Moreover, it may be necessary to continue lithium beyond the first relapses to restore long-term prophylactic efficacy.

Phenotypic clustering of bipolar disorder supports stratification by lithium responsiveness over diagnostic subtypes.

INTRODUCTION: The aim of this study was to determine whether the clinical profiles of bipolar disorder (BD) patients could be differentiated more clearly using the existing classification by diagnostic subtype or by lithium treatment responsiveness. METHODS: We included adult patients with BD-I or II (N = 477 across four sites) who were treated with lithium as their principal mood stabilizer for at least 1 year. Treatment responsiveness was defined using the dichotomized Alda score. We performed hierarchical clustering on phenotypes defined by 40 features, covering demographics, clinical course, family history, suicide behaviour, and comorbid conditions. We then measured the amount of information that inferred clusters carried about (A) BD subtype and (B) lithium responsiveness using adjusted mutual information (AMI) scores. Detailed phenotypic profiles across clusters were then evaluated with univariate comparisons. RESULTS: Two clusters were identified (n = 56 and n = 421), which captured significantly more information about lithium responsiveness (AMI range: 0.033 to 0.133) than BD subtype (AMI: 0.004 to 0.011). The smaller cluster had disproportionately more lithium responders (n = 47 [83.8%]) when compared to the larger cluster (103 [24.4%]; p = 0.006). CONCLUSIONS: Phenotypes derived from detailed clinical data may carry more information about lithium responsiveness than the current classification of diagnostic subtype. These findings support lithium responsiveness as a valid approach to stratification in clinical samples.

Prevention of suicidal behavior with lithium treatment in patients with recurrent mood disorders.

Suicidal behavior is more prevalent in bipolar disorders than in other psychiatric illnesses. In the last thirty years evidence has emerged to indicate that long-term treatment of bipolar disorder patients with lithium may reduce risk of suicide and attempts, with possibly similar benefits in recurrent major depressive disorder. We review and update selected research literature on effects of lithium treatment in reducing suicidal behavior and consider proposals that higher levels of lithium in drinking water may be associated with lower suicide rates. We summarize results of a growing number of randomized, controlled studies of lithium treatment for suicide prevention including comparisons with placebos or alternative treatments, and comment on the severe challenges of such trials. The basis of a proposed protective effect of lithium against suicidal behaviors remains uncertain but may include protective effects against recurrences of depressive phases of mood disorders, especially with mixed features or agitation, and possibly through beneficial effects on impulsivity, agitation and dysphoric mood.

Current Status and Treatment of Rapid Cycling Bipolar Disorder.

BACKGROUND: Rapid cycling (RC) at least 4 recurrent episodes per year in bipolar disorder (BD) has been recognized since the 1970s. We now comment on our recent review of the topic and extensive RC analysis in a large clinical cohort, emphasizing therapeutics research. COMMENTS: Prevalence of RC-BD averages 36% for any year versus 22% in the preceding year. Rapid cycling is not a consistent feature over many years, although average long-term, annual recurrence rates are greater in RC-BD patients. Risk of RC may be somewhat greater among women and with older ages. It is also associated with cyclothymic temperament, prominent depression, and mood-switching with antidepressant treatment and is associated with increased suicidal risk. Treatment of individual episodes in RC-BD and effective long-term prevention remain inadequately studied, although antidepressant treatment can worsen RC. Some research supports treatment with aripiprazole, lamotrigine, and lithium, and interest in second-generation antipsychotics is emerging. All such options are used in various inadequately evaluated combinations. CONCLUSIONS: Rapid cycling is prevalent among BD patients but seems to vary in risk over time without evidence of progressive worsening. Treatment of acute episodes in RC-BD patients and effective long-term preventive management require much more intensive investigation.

Early sexual or physical abuse in female and male mood disorder patients.

Early abuse has been associated with psychiatric morbidity but comparisons of bipolar (BD) and major depressive (MDD) disorder subjects with versus without early sexual or physical abuse are rare. Patients (n = 684) diagnosed with a DSM-5-TR major mood disorder were evaluated and followed for several years at mood disorder centers to compare details of history and clinical status in participants with versus without early sexual or physical abuse. Early history of sexual (16.2%) or physical abuse (11.9%) was prevalent; 5.15% reported both. Both types of abuse were much more prevalent with BD than MDD. Sexual abuse was associated with younger illness-onset and somewhat younger menarche in females; both abuse-types were associated with familial mood disorders, especially BD. Prospective, long-term illness episode-frequency, depressions or [hypo]manias/year and %-time [hypo]manic all were greater following sexual abuse but morbidity measures did not differ following physical abuse. Prevalence of suicidal behavior ranked: double (48.5%) > physical (32.1%) > sexual (30.3%) abuse, and with BD > MDD (OR = 2.31). Recall bias and not using psychometric instruments to define abuse severity or type may limit interpretation of findings. Early sexual (more than physical) abuse, led to greater morbidity and both abuses were strongly associated with familial mood disorders and greater suicidal risk, especially with double-abuse and BD diagnosis. We support a bilateral relationship between abuse and diagnosis of BD: abuse may facilitate early appearance of BD but also may result from the actions of abusive BD family members.

Status of Type II vs. Type I Bipolar Disorder: Systematic Review with Meta-Analyses.

LEARNING OBJECTIVES AFTER PARTICIPATING IN THIS CME ACTIVITY, THE PSYCHIATRIST SHOULD BE BETTER ABLE TO: • Analyze and compare the different bipolar disorder (BD) types.• Identify markers that distinguish BD types and explain how the DSM-IV defines the disorder. ABSTRACT: Since the status of type II bipolar disorder (BD2) as a separate and distinct form of bipolar disorder (BD) remains controversial, we reviewed studies that directly compare BD2 to type I bipolar disorder (BD1). Systematic literature searching yielded 36 reports with head-to-head comparisons involving 52,631 BD1 and 37,363 BD2 patients (total N = 89,994) observed for 14.6 years, regarding 21 factors (with 12 reports/factor). BD2 subjects had significantly more additional psychiatric diagnoses, depressions/year, rapid cycling, family psychiatric history, female sex, and antidepressant treatment, but less treatment with lithium or antipsychotics, fewer hospitalizations or psychotic features, and lower unemployment rates than BD1 subjects. However, the diagnostic groups did not differ significantly in education, onset age, marital status, [hypo]manias/year, risk of suicide attempts, substance use disorders, medical comorbidities, or access to psychotherapy. Heterogeneity in reported comparisons of BD2 and BD1 limits the firmness of some observations, but study findings indicate that the BD types differ substantially by several descriptive and clinical measures and that BD2 remains diagnostically stable over many years. We conclude that BD2 requires better clinical recognition and significantly more research aimed at optimizing its treatment.

Suicidal risk and protective factors in major affective disorders: A prospective cohort study of 4307 participants.

BACKGROUND: Suicidal behavior is strongly associated with major affective disorders, but there is a need to quantify and compare specific risk and protective factors in bipolar disorder (BD) and major depressive disorder (MDD). METHODS: In 4307 extensively evaluated major affective-disorder participants with BD (n = 1425) or MDD (n = 2882) diagnosed by current international criteria, we compared characteristics among those with versus without suicidal acts from illness-onset through 8.24 years of follow-up. RESULTS: Suicidal acts were identified in 11.4 % of participants; 25.9 % were violent and 6.92 % (0.79 % of all participants) were fatal. Associated risk factors included: diagnosis (BD > MDD), manic/psychotic features in first-episodes, family history of suicide or BD, separation/divorce, early abuse, young at illness-onset, female sex with BD, substance abuse, higher irritable, cyclothymic or dysthymic temperament ratings, greater long-term morbidity, and lower intake functional ratings. Protective factors included marriage, co-occurring anxiety disorder, higher ratings of hyperthymic temperament and depressive first episodes. Based on multivariable logistic regression, five factors remained significantly and independently associated with suicidal acts: BD diagnosis, more time depressed during prospective follow-up, younger at onset, lower functional status at intake, and women > men with BD. LIMITATIONS: Reported findings may or may not apply consistently in other cultures and locations. CONCLUSIONS: Suicidal acts including violent acts and suicides were more prevalent with BD than MDD. Of identified risk (n = 31) and protective factors (n = 4), several differed with diagnosis. Their clinical recognition should contribute to improved prediction and prevention of suicide in major affective disorders.

Characteristics of rapid cycling in 1261 bipolar disorder patients.

BACKGROUND: Rapid-cycling (RC; ≥ 4 episodes/year) in bipolar disorder (BD) has been recognized since the 1970s and associated with inferior treatment response. However, associations of single years of RC with overall cycling rate, long-term morbidity, and diagnostic subtypes are not clear. RESULTS: We compared descriptive and clinical characteristics in 1261 BD patients with/without RC, based on history and prospective follow-up for several years. RC in any previous year was identified in 9.36% of BD subjects (3.74% in BD1, 15.2% BD2), and somewhat more among women than men. RC-BD subjects had 3.21-fold greater average prospective annual rates of recurrence but not hospitalizations, had less difference in %-time-ill, received more mood-stabilizing treatments, and had greater suicidal risk, lacked familial psychiatric illnesses, had more cyclothymic temperament, were more likely to be married, had more siblings and children, experienced early sexual abuse, but were less likely to abuse drugs (not alcohol) or smoke. In multivariable regression modeling, older age, mood-switching with antidepressants, and BD2 > BD1 diagnosis, as well as more episodes/year were independently associated with RC. Notably, prospective mean recurrence rates were below 4/year in 79.5% of previously RC patients, and below 2/year in 48.1%. CONCLUSIONS: Lifetime risk of RC in BD was 9.36%, more likely in women, with older age, and in BD2 > BD1. With RC, recurrence rates were much higher, especially for depression with less effect on %-time ill, suggesting shorter episodes. Variable associations with unfavorable outcomes and prospective recurrence rates well below 4/year in most previously RC patients indicate that RC was not a sustained characteristic and probably was associated with use of antidepressants.

A genome-wide association study of antidepressant-induced mania.

Antidepressant-induced mania (AIM) is a side effect of antidepressant treatment that is characterized by mania or hypomania after the start of medication. It is likely polygenic, but its genetic component remains largely unexplored. We aim to conduct the first genome-wide association study of AIM in 814 bipolar disorder patients of European ancestry. We report no significant findings from our single-marker or gene-based analyses. Our polygenic risk score analyses also did not yield significant results with bipolar disorder, antidepressant response, or lithium response. Our suggestive findings on the hypothalamic-pituitary-adrenal axis and the opioid system in AIM require independent replications.

Comparison of bipolar disorder type II and major depressive disorder.

OBJECTIVE: Compare patients diagnosed as DSM-5 type II bipolar disorder (BD2) vs. major depressive disorder (MDD). METHODS: We compared characteristics of 3246 closely and repeatedly evaluated, consenting, adult patient-subjects (n = 706 BD2, 2540 MDD) at a specialty clinic using bivariate methods and multivariable modeling. RESULTS: Factors more associated with BD2 than MDD included: [a] descriptors (more familial psychiatric, mood and bipolar disorders and suicide; younger at onset, diagnosis and first-treatment; more education; more unemployment; fewer marriages and children; higher cyclothymic, hyperthymic and irritable temperament ratings, lower anxious); [b] morbidity (more hypomanic, mixed or panic first episodes; more co-occurring general medical diagnoses, more Cluster B personality disorder diagnoses and ADHD; more alcohol and drug abuse and smoking; shorter depressive episodes and interepisode periods; lower intake ratings of depression and anxiety, higher for hypomania; far more mood-switching with antidepressants; lower %-time depressed; DMI > MDI course-pattern in BD2; more suicide attempts and violent suicidal behavior); [c] item-scores with intake HDRS21 higher for suicidality, paranoia, anhedonia, guilt, and circadian variation; lower somatic anxiety, depressed mood, insight, hypochondriasis, agitation, and insomnia; and [d] treatment (more lithium, mood-stabilizing anticonvulsants and antipsychotics, less antidepressants and benzodiazepines). CONCLUSIONS: BD2 and MDD subjects differed greatly in many descriptive, psychopathological and treatment measures, notably including more familial risk, earlier onset, more frequent recurrences and greater suicidal risk with BD2. Such differences can contribute to improving differentiation of the disorders and planning for their treatment.

Affective temperaments mediate aggressive dimensions in bipolar disorders: A cluster analysis from a large, cross-sectional, international study.

BACKGROUND: Affective temperaments show potential for aggressive behavior (AB) preventive strategies in bipolar disorder (BD). We aim to define intra-diagnostic subgroups of patients with BD based on homogeneous behaviors related to AB. Subsequently, to assess whether affective temperament dimensions may contribute to the presence and severity of AB. METHODS: Patients with BD were recruited. AB was evaluated through the modified overt aggression scale (MOAS); affective temperaments were assessed with the TEMPS-A. A cluster analysis was conducted based on TEMPS-A and MOAS scores. Stepwise backward logistic regression models were used to identify the predictive factors of cluster membership. RESULTS: 799 patients with BD were enrolled. Three clusters were determined: non-aggressive (55.5 %), self-aggressive (18 %), and hetero-aggressive (26.5 %). Depressive, irritable, and anxious temperament scores significantly increased from the non-aggressive (lower) to the self-aggressive (intermediate) and the hetero-aggressive group (highest). A positive history of a suicide attempt (B = 5.131; OR = 169.2, 95 % CI 75.9; 377) and rapid cycling (B = -0.97; OR = 0.40, 95 % CI 0.17; 0.95) predicted self-aggressive cluster membership. Atypical antipsychotics (B = 1.19; OR = 3.28, 95 % CI 2.13; 5.06) or SNRI treatment (B = 1.09; OR = 3, 95 % CI 1.57; 5.71), psychotic symptoms (B = 0.73; OR = 2.09, 95 % CI 1.34; 3.26), and history of a suicide attempt (B = -1.56; OR = 0.20, 95 % CI 0.11; 0.38) predicted hetero-aggressive cluster membership. LIMITATIONS: Recall bias might have affected the recollection of AB. CONCLUSIONS: Clinical factors orientate the prevention of different ABs in BD. Affective temperaments might play a role in preventing AB since patients with more pronounced affective temperaments might have an increased risk of showing AB, in particular hetero-AB.

Prevention of Suicidal Behavior in Bipolar Disorder.

Background: Excess mortality is a critical hallmark of bipolar disorder (BD) due to co-occurring general medical disorders and especially from suicide. It is timely to review of the status of suicide in BD and to consider the possibility of limiting suicidal risk. Methods: We carried out a semi-systematic review of recent research reports pertaining to suicide in BD. Findings: Suicide risk in BD is greater than with most other psychiatric disorders. Suicide rates (per 100,000/year) are approximately 11 and 4 in the adult and juvenile general populations, but over 200 in adults, and 100 among juveniles diagnosed with BD. Suicide attempt rates with BD are at least 20 times higher than in the adult general population, and over 50 times higher among juveniles. Notable suicidal risk factors in BD include: previous suicidal acts, depression, mixed-agitated-dysphoric moods, rapid mood-shifts, impulsivity, and co-occurring substance abuse. Suicide-preventing therapeutics for BD remain severely underdeveloped. Evidence favoring lithium treatment is stronger than for other measures, although encouraging findings are emerging for other treatments. Conclusions: Suicide is a leading clinical challenge for those caring for BD patients. Improved understanding of risk and protective factors combined with knowledge and close follow-up of BD patients should limit suicidal risk. Ethically appropriate and scientifically sound studies of plausible medicinal, physical, and psychosocial treatments aimed at suicide prevention specifically for BD patients are urgently needed.Reprinted from Bipolar Disord 2021; 23:14-23, with permission from John Wiley and Sons. Copyright © 2021.

Lithium induced hypercalcemia: an expert opinion and management algorithm.

BACKGROUND: Lithium is the gold standard prophylactic treatment for bipolar disorder. Most clinical practice guidelines recommend regular calcium assessments as part of monitoring lithium treatment, but easy-to-implement specific management strategies in the event of abnormal calcium levels are lacking. METHODS: Based on a narrative review of the effects of lithium on calcium and parathyroid hormone (PTH) homeostasis and its clinical implications, experts developed a step-by-step algorithm to guide the initial management of emergent hypercalcemia during lithium treatment. RESULTS: In the event of albumin-corrected plasma calcium levels above the upper limit, PTH and calcium levels should be measured after two weeks. Measurement of PTH and calcium levels should preferably be repeated after one month in case of normal or high PTH level, and after one week in case of low PTH level, independently of calcium levels. Calcium levels above 2.8 mmol/l may require a more acute approach. If PTH and calcium levels are normalized, repeated measurements are suggested after six months. In case of persistent PTH and calcium abnormalities, referral to an endocrinologist is suggested since further examination may be needed. CONCLUSIONS: Standardized consensus driven management may diminish the potential risk of clinicians avoiding the use of lithium because of uncertainties about managing side-effects and consequently hindering some patients from receiving an optimal treatment.

Factors associated with onset-age in major affective disorders.

BACKGROUND: Research findings on factors associated with onset-age (OA) with bipolar (BD) and major depressive disorders (MDD) have been inconsistent, but often indicate greater morbidity following early OA. METHODS: We considered factors associated with OA in 1033 carefully evaluated, systematically followed mood disorder subjects with DSM-5 BD (n = 505) or MDD (n = 528), comparing rates of descriptive and clinical characteristics following early (age <18), intermediate (18-40), or later onset (≥40 years), as well as regressing selected measures versus OA. Exposure time (years ill) was matched among these subgroups. RESULTS: As hypothesized, many features were associated with early OA: familial psychiatric illness, including BD, greater maternal age, early sexual abuse, nondepressive first episodes, co-occurring ADHD, suicide attempts and violent suicidal behavior, abuse of alcohol or drugs, smoking, and unemployment. Other features increased consistently with later OA: %-time-depressed (in BD and MDD, women and men), as well as depressions/year and intake ratings of depression, educational levels, co-occurring medical disorders, rates of marriage and number of children. CONCLUSIONS: OA averaged 7.5 years earlier in BD versus MDD (30.7 vs. 38.2). Some OA-associated measures may reflect maturation. Associations with family history and suicidal risk with earlier OA were expected; increases of time-depressed in both BD and MDD with later OA were not. We conclude that associations of OA with later morbidity are complex and not unidirectional but may be clinically useful.

Effects of Treatment of Acute Major Depressive Episodes in Bipolar I Versus Bipolar II Disorders With Quetiapine.

BACKGROUND: Several second-generation antipsychotic drugs (SGAs) have evidence of benefit for acute major depressive episodes in bipolar disorder (BD) patients. However, their comparative efficacy in types I vs II BD (BD1 vs BD2) remains uncertain. METHODS: We carried out a systematic literature search for randomized, double-blinded, controlled treatment trials for acute major depressive episodes involving head-to-head comparisons of BD1 versus BD2 subjects, followed by meta-analyses and meta-regression modeling. RESULTS: Seven reports met out inclusion criteria, yielding 22 comparisons of SGA versus placebo averaging 8.3 weeks in duration. All trials involved quetiapine, which was much more effective than placebo (pooled standardized mean difference [SMD] = 1.76 [95% confidence interval, 1.40-2.12], P < 0.0001). Estimated % improvement averaged 53.5% [46.5-60.5] with quetiapine vs 39.8% [34.2-45.4] with placebo ( P < 0.0001); their ratio was somewhat larger with BD1 (1.56 [1.26-1.86]) versus BD2 subjects (1.22 [1.07-1.37], P = 0.04; as was SMD (BD1: 2.35 [1.83-2.86]; BD2: SMD = 1.44 [1.05-1.82]). Meta-regression found diagnosis (BD1 > BD2) to be the only factor significantly associated with the meta-analytic outcome. CONCLUSIONS: Although data are limited, depressed BD1 patients may respond somewhat better to quetiapine than BD2. Additional head-to-head diagnostic comparisons are needed with other SGAs, as well as evaluation of monotherapy versus various combinations that include SGAs in both short- and long-term use.