Objectives. The aim of the study was to investigate the efficacy of long-term lithium administration in a large group of patients with bipolar disorder (BP) and to define factors associated with the efficacy of lithium treatment.
Material and methods. The study included 111 patients (76 women, 35 men), aged 34-85 (mean age 61 years) receiving lithium for 5-39 years (mean length 18 years). Lithium efficacy was assessed using a three-step scale identifying Excellent Responders (ER), Partial Responders (PR) and Non-Responders (NR), as well as the Alda Scale rating lithium efficacy within the range of 0-10. Various clinical factors that can be linked with lithium efficacy were also analysed, including age at onset of the illness, polarity of the first episode, age at the first occurrence of elevated or depressed mood, number of affective episodes preceding lithium treatment, duration of the illness prior to lithium treatment, type of BP (I or II), family history of affective illness, comorbidity of anxiety disorder, obsessive-compulsive disorder, posttraumatic stress disorder, alcohol and medication abuse/dependence, suicide attempts preceding lithium therapy and the duration of lithium treatment.
Results. Among the patients studied, 27% met the criteria for ER, 63% for PR and 10% for NR. The mean score on the Alda scale was 6.6±2.5. A better effect of lithium prophylaxis was shown in patients with a later onset of the illness, without a family history of affective illness, having family members who receive lithium, in women with comorbid anxiety disorder and in men without alcohol abuse/dependence.
Conclusions. There are no recurrences of BP in about 30% of patients in long-term lithium treatment, independently of the duration of lithium administration. Also, in the present study, several other factors were identified connected with lithium efficacy.