Most (97%) of people in this study with co-occurring diagnoses of both bipolar disorder I and alcohol or drug abuse disorders had attempted suicide.
Sublette et al, (2009). Substance use disorder and suicide attempts in bipolar subtypes
Journal of Psychiatric Research Vol 43 #3, p. 230-238

A comparison of 39 bipolar I disorder clients with 53 healthy controls found that regardless of suicidal history, people with bipolar I scored lower on neuropsychological tests of memory, executive function, attention and decision-making. Those who had attempted suicide had lower performance on decision-making tests compared to those who had not. Caution: the small sample may detract from the validity of these findings.
Malloy-Diniz, L.F. et al (2009). Suicide behavior and neuropsychological assessment of Type I bipolar patients. Journal of Affective Disorders, Vol 112 #1-3, p. 231-236.

Electroconvulsive therapy (ECT) was found to have more effectiveness in subjective & objective measures of mood in people diagnosed with unipolar depression than in people with bipolar depression, where there was no improvement in subjective (client) measures of mood. In the latter only clinician-rated measures were found to have improvement. In people with unipolar depression, improvement was shown on both clinician (objective) and client (subjective) measures of improvement. The study suggests that ECT may be more useful for people with unipolar depression than those with bipolar depression.
Hallam, K.T., Smith, D. I., & Berk, M. (2009). Differences between subjective and objective assessments of the utility of electroconvulsive therapy in patients with bipolar and unipolar depression. Journal of Affective Disorders, Vol 112 #1-3, p. 212-218

Although no causal relationship can be determined from this cross-sectional study, children and adolescents with a history of physical abuse were more likely to have longer duration of bipolar disorder, non-intact family, PTSD, psychosis and first degree family history of mood disorder than those without a history of physical abuse.
Romero, S. et al (2009). Prevalence and correlates of physical and sexual abuse in children and adolescents with bipolar disorder. Journal of Affective Disorders, Vol 112 #1-3, p. 144-150

A small study (results to be taken with caution) explored the effectiveness of psychoeducation as compared to an unstructured support group for people diagnosed with bipolar II. Results showed that after 5 years people who were in the psychoeducation group had fewer and shorter bipolar episodes and fewer manic and depressive episodes with higher levels of functioning.
Colom, F. et al (2009). Psychoeducation for bipolar II disorder: an exploratory, 5-year outcome sub-analysis. Journal of Affective Disorders, Vol 112 #1-3, p. 30-35