Prophylactic treatment response in bipolar disorder: results of a naturalistic observation study.

BACKGROUND: The objective of this study was to evaluate effectiveness of commonly used prophylactic treatments for bipolar disorder in a naturalistic setting and to explore factors associated with treatment response. METHODS: We reviewed charts of 120 patients with a confirmed diagnosis of bipolar I or bipolar II disorder. The sample consisted of 37 males and 83 females, in the age range of 20 to 81 years (mean age 45+/-14 years), treated at an outpatient psychiatry program in a teaching hospital. In contrast to controlled clinical trials, we did not exclude subjects with co-morbid conditions and/or substance abuse. Treatment outcome was evaluated using a scale for retrospective assessment of prophylactic treatment response. The scale rates the degree of improvement in the course of treatment weighted by the likelihood of response being attributable to the treatment. The inter-reliability of the assessments was good with concordance of ratings of 90% and weighted kappa of 0.8. RESULTS: Rates of full response to individual mood stabilizers were: lithium 30%, carbamazepine 0%, valproate 13%, lamotrigine 11%, and olanzapine 25%. Lithium responders were more likely to be bipolar II, and had a typically episodic course of illness with earlier onset in comparison with non-responders. Responders to valproate had higher rates of psychosis. LIMITATIONS: Data were obtained by chart reviews. CONCLUSIONS: Less than one-third of patients treated with lithium achieved remission; the effectiveness of other treatments in this naturalistic sample was even lower.

Phenotypic spectra of bipolar disorder in responders to lithium versus lamotrigine.

OBJECTIVE: We conducted a study of clinical presentation and family history in patients responsive to either of two commonly used mood stabilizers, lithium and lamotrigine. METHODS: The sample included 164 subjects from 21 families of bipolar probands, 14 responders to lithium and seven to lamotrigine. Diagnostic information on first-degree relatives was obtained in a blind fashion through a combination of direct interviews (SADS-L) and family history assessments (FH-RDC). RESULTS: The probands differed with respect to clinical course (episodic in the lithium group, rapid cycling in the lamotrigine group), and comorbidity (panic attacks and substance abuse in the lamotrigine group). The relatives of lithium responders had significantly higher risk of bipolar disorder while relatives of lamotrigine responders had higher prevalence of schizoaffective disorder, major depression and panic attacks. CONCLUSIONS: These findings suggest that lithium- and lamotrigine-responsive patients differ with respect to course of illness, comorbidity and family history and may represent distinct subtypes of bipolar disorder.