Attrition factors in clinical trials of comorbid bipolar and substance-related disorders.
BACKGROUND
This study analyzed and defined specific factors that account for attrition in clinical research for patients with bipolar and substance-related disorders.


METHODS
Data were analyzed from two completed studies: an open-label trial of lamotrigine in patients with bipolar disorder (BPD) and cocaine-related disorder, and a placebo-controlled trial of quetiapine in patients with BPD and alcohol-related disorders. Correlations and Independent sample t-tests were performed to assess the impact of baseline characteristics including on length of study participation. Significance was set at the p=0.05 level.


RESULTS
In the lamotrigine-treated patients, the presence of an amphetamine-related disorder, in addition to cocaine-related disorders, was associated with a shorter time in the study. In the quetiapine-treated patients higher scores on the Addiction Severity Index Legal subscale were associated with shorter length in the study. The presence of panic disorder was associated with shorter time in both studies.


CONCLUSIONS
Although the data were taken from the two largest clinical trials, to date, in patients with BPD and substance-related disorders, the sample sizes were relatively modest. In addition, the baseline assessments were somewhat different in the two studies limiting our ability to make conclusions on differences between patients with BPD and cocaine use versus alcohol use.


CONCLUSIONS
This study adds to an emerging literature on the significance of panic disorder in patients with BPD.
Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States.
Nicole
N
Nomamiukor
E Sherwood
ES
Brown
D000328:Adult; D019973:Alcohol-Related Disorders / Q000188:drug therapy / Q000453:epidemiology; D019969:Amphetamine-Related Disorders / Q000188:drug therapy / Q000453:epidemiology; D000927:Anticonvulsants / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D019970:Cocaine-Related Disorders / Q000188:drug therapy / Q000453:epidemiology; D015897:Comorbidity; D017831:Diagnosis, Dual (Psychiatry); D003987:Dibenzothiazepines / Q000627:therapeutic use; D005260:Female; D006801:Humans; D000077213:Lamotrigine; D008297:Male; D016584:Panic Disorder / Q000188:drug therapy / Q000453:epidemiology; D010352:Patient Dropouts / Q000706:statistics & numerical data; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D000069348:Quetiapine Fumarate; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D012720:Severity of Illness Index; D019966:Substance-Related Disorders / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D013997:Time Factors; D014227:Triazines / Q000627:therapeutic use
D000927:Anticonvulsants; D014150:Antipsychotic Agents; D003987:Dibenzothiazepines; D014227:Triazines; D000069348:Quetiapine Fumarate; D000077213:Lamotrigine