Bipolar disorder (BD) patients with elevated body mass index (BMI) are more likely to experience a more severe disease course in terms of chronicity, duration of illness, and overall functioning, suggest study results.

“Our study has further identified this subgroup as lithium nonresponders, who may represent a particular phenotype of BD patients with a distinct pathophysiology and less favorable outcome,” add Martin Alda (Dalhousie University, Halifax, Nova Scotia, Canada) and colleagues.

Obesity is common in patients with BD, with a 20??”49% prevalence, compared with 18% in the general US population.

To investigate the relationship between elevated BMI and prognosis and outcome in BD, Alda and team investigated differences in sociodemographic, clinical, and medical characteristics with respect to BMI in 276 tertiary care patients with BD.

In total, 39.1% of patients were classified as obese (BMI of ?30 kg/m²)and 36.6% as overweight (BMI of ?25??”30 kg/m²), with no difference in BMI distribution between BD type I and II.

Obese patients were generally not responsive to lithium and had a more chronic, fluctuating course of illness than those with lower BMIs. These patients also had a longer duration of illness, lower global assessment of functioning scores, higher rates of disability, and more comorbid subthreshold anxiety and personality disorders than those with lower BMIs.

The authors also found that patients who achieved complete remission of psychiatric symptoms on lithium had a significantly lower BMI compared with those who showed partial or no therapeutic benefit (mean of 32.4 kg/m² vs 30.0 and 26.5 kg/m², respectively) ??” a finding that is at odds with reports stating that most mood stabilizers cause weight gain.

Commenting on this finding, the researchers write in the journal Bipolar Disorders: “We speculate that lithium-responsive patients spend more time in a state of wellness and are better able to exercise and follow a healthy diet.”

Alda and team add that the subgroup of BD patients with high BMI and poor prognosis “may have impaired metabolism that could underlie obesity, diabetes mellitus Type II, and response to lithium.

They suggest that until a prospective study is performed to assess causality, physicians should provide nutrition and exercise counseling, and screen for and treat the metabolic syndrome and risk factors for cardiovascular disease in this group of BD patients.

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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UK researchers have found that depressive and social anxiety symptoms are more severe among tertiary care outpatients with anxiety disorders than among those with unipolar or bipolar depression.

However, the correlation between depressive and social anxiety symptoms in outpatients with anxiety disorders was neglible, the researchers note.

“These findings emphasize the need for comprehensive evaluation and treatment of secondary depression in patients with primary anxiety disorders,” say D Baldwin (University of Southampton) and co-authors.

For their study, the researchers included 75 patients (mean age 46 years) attending a tertiary referral mood and anxiety disorders service, of whom 15 were classified as having bipolar disorder, 35 had unipolar depression, and 19 had anxiety disorders. Depressive symptoms were assessed using the Montgomery??Ӂsberg Depression Rating Scale (MADRS) and social anxiety symptoms by the Liebowitz Social Anxiety Scale (LSAS).

Overall, patients had mean MADRS and LSAS scores of 20.1 and 63.4, respectively, corresponding to moderate intensity depression and anxiety. The authors also found a mean Clinical Global Impression of Severity (CGI-S) score of 3.5, corresponding to mild-to-moderate illness severity.

Patients with anxiety disorders had significantly higher LSAS (78.8 vs 50.0 and 59.4) and CGI-S (3.9 vs 3.1 and 3.3) scores than patients with bipolar or unipolar depression, respectively. LSAS and CGI-S scores were also significantly higher in patients with co-morbid diagnoses (n=37) than in patients with single diagnoses.

Baldwin et al further found a weak correlation between the severity of depressive and social anxiety symptoms in all patients, although both symptoms strongly correlated with overall illness severity.

Furthermore, the strongest correlation between MADRS and LSAS scores was seen in the bipolar group. This correlation was not seen in patients with anxiety disorders.

“The lack of correlation seen in the primary anxiety disorders group is probably explained by the broad range of diagnoses within that group, only 26% of whom had a primary diagnosis of social phobia,” write the authors in the Journal of Affective Disorders.

The team concludes: “Attempts should be made to clarify the determinants of greater social anxiety symptom severity in patients with more severe depressive symptoms.”

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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