Objective: In a recent 6-month, randomized, placebo-controlled, double-blind trial that enrolled subjects with bipolar I disorder and a Mania Rating Scale (MRS) score ≥ 14, ziprasidone was found to be an effective, safe, and well-tolerated adjunctive treatment in combination with a mood stabilizer. To further elucidate the profile of subjects who received the most benefit from ziprasidone treatment, treatment outcomes across a spectrum of illness severity were determined.
Methods: The proportion of subjects randomized to double-blind treatment (subjects achieving ≥ 8 consecutive weeks of stability with open-label ziprasidone [80–160 mg/day] and lithium or valproate) was determined for patients with baseline Clinical Global Impression-Severity (CGI-S) scores < 5 (mild to moderately ill) and CGI-S ≥ 5 (severely ill). The proportion of mild to moderately ill and severely ill subjects who relapsed during double-blind treatment was also determined.
Results: A higher proportion of subjects rated mild to moderately ill (n = 185/434, 42.6%) were randomized to double-blind treatment, compared with the proportion of subjects rated severely ill (n = 54/149, 36.2%). Among mild to moderately ill subjects, rates of relapse for patients randomized to ziprasidone were lower than for subjects randomized to placebo (18.4% vs 32.6%). For severely ill subjects, rates of relapse for patients randomized to ziprasidone were also lower than for subjects randomized to placebo (24.1% vs 33.3%).
Conclusion: These analyses indicate that adjunctive ziprasidone treatment was similarly beneficial in mild to moderately ill subjects and in severely ill subjects.