Investigating symptom domains of bipolar disorder for Spanish-speakers using the Bipolar Inventory of Symptoms Scale

Background A Spanish language rating scale which assesses the range of bipolar disorder symptoms is needed. There are rating scales commonly used, however they do not address commonly expressed symptoms associated with bipolar disorder and have varied rating systems. There are also few comparisons of symptom severity between Spanish and English speaking patients, due to limitations in available rating scales. Methods We conducted psychometric assessment of the Spanish language Bipolar Inventory of Symptoms Scale (BISS) (N=71) for persons with bipolar disorder, which assesses 5 domains: mania, depression, irritability, anxiety and psychosis. The Spanish BISS scores were then compared to the MADRS (Montgomery Asberg Depression Rating Scale) and the YMRS (Young Mania Rating Scale) as well as to BISS scores in an English speaking sample (N=102) with bipolar disorder from the same geographic locations. Results Chronbach's alphas for the Spanish BISS ranged from 0.6 to 0.93, with the psychosis domain displaying lower reliability. Correlations with the MADRS and YMRS were good and ranged from 0.70 to 0.88. The BISS differentiated well across mood states in English and Spanish versions, with mood state differentiated well using subscales and domains. For the irritability and anxiety domains, Spanish speaking participants had higher scores than English speakers across mood states. Females showed differences in symptom profiles compared to males. Limitations The sample sizes in the Spanish speaking manic group were small. The Spanish BISS, tested here primarily in patients of Mexican ancestry, may require revision in other Spanish language populations. Conclusions The Spanish BISS, a Spanish language symptom rating scale for bipolar disorder, demonstrates good reliability and validity. Clinical assessment in anxiety and irritability domains is particularly relevant in a Spanish speaking sample. Consistent with prior research, females report higher depression, irritability and anxiety scores irrespective of language spoken.