Difference between Symptomatic, Syndromal, and Functional Recovery in Bipolar II Disorder: Treatment Considerations

Background: Bipolar disorders (BD) are a leading cause of disability worldwide. The majority of individuals with BD demonstrate substantial disability in functioning even in times of remission (symptomatic recovery). A marked difference has been documented consistently between improvement in symptoms (syndromal recovery) and restored functioning (functional recovery) for individuals with BDs, with restoration of functioning typically lagging behind improvement in mood symptoms. Few studies have examined the unique recovery trajectories of individuals with bipolar II disorder (BDII). This study examines differences in recovery rates (i.e. symptomatic, syndromal, and functional) and whether these differ when participants received medication in addition to Interpersonal Social Rhythms Therapy (IPSRT).

Methods: The sample consisted of individuals meeting DSM IV criteria for BDII, currently depressed (n=77), randomly assigned to receive Interpersonal and Social Rhythm Therapy (IPSRT) plus placebo or IPSRT plus quetiapine and treated for 20 weeks. Kaplan Meir survival analysis was used to calculate rates of recovery (i.e. symptomatic, syndromal, functional) at eight, 12, and 20 weeks. Log rank tests examined treatment effect. Symptomatic recovery was operationalized as three consecutive weeks with depressive and manic symptoms below clinical cut off [Hamilton Rating Scale for Depression 25 item (HDRS-25) ≤ 8 and Young Mania Rating Scale (YMRS) ≤ 8]. Syndromal recovery was operationalized as ≥ 50% reduction in depressive symptoms measured using the HDRS-25. Functional recovery was defined dichotomously by the clinical cut off point on the Functional Assessment Short Test (FAST) (i.e. ≤ 11 = impaired). Z-tests were used to determine if there was a significant difference between rates of different types of recovery (i.e. symptomatic, syndromal, and functional) at different time points (i.e. 8 weeks, 12 weeks, and 20 weeks) between the two treatment groups (i.e. IPSRT+placebo v. IPSRT+quetiapine).

Results: Survival curves did not differ significantly between groups [symptomatic recovery X² (1, N=77) = 0.62, p=0.4315; syndromal recovery X² (1, N=77) = 3.11, p=0.0779; functional recovery X² (1, N=77) = 0.56, p=0.4529]. At eight weeks 9% of participants had reached symptomatic recovery, 59% had reached syndromal recovery, and 20% had reached functional recovery. At 12 weeks recovery rates were 15% symptomatic, 79% syndromal, and 30% functional. At the end of treatment (20 weeks) recovery rates were 50% symptomatic, 89% syndromal, and 88% functional. There was a significant difference between all different forms of recovery rates at all time points examined (P ≤ 0.05), except by week 20 of treatment there was not a significant difference between syndromal and functional recovery rates.

Conclusions: Results suggests individuals with BDII can achieve recovery regardless of whether they receive medication in addition to psychotherapy. The majority of individuals reached all types of recovery but functional recovery required longer time than reduction of active symptoms. Longer, more intensive, or combination treatments may be needed to achieve remission for up to half of individuals with BD II depression. Limitations include absence of inactive comparison and medication-only treatment groups, high attrition, and small sample.