SAN JUAN, P.R. – Risperidone and ziprasidone increased adherence to inpatient substance abuse treatment for people with schizophrenia or schizoaffective disorder in a comparison that also included olanzapine and typical neuroleptic agents, Elizabeth B. Stuyt, M.D., said at the annual meeting of the American Academy of Addiction Psychiatry.
In the retrospective study, the risperidone (Risperdal) and ziprasidone (Geodon) groups experienced increased length of stay in substance abuse treatment, a higher completion rate, and greater behavioral improvements.
Cigarette smoking may play an important role, said Dr. Stuyt, lead researcher. All 55 participants smoked at baseline, and constituents of cigarette smoke activate the same cytochrome P-450 system enzyme that metabolizes olanzapine (Zyprexa), haloperidol decanoate (Haldol), and fluphenazine decanoate. This enzyme does not metabolize risperidone or ziprasidone, said Dr. Stuyt of the University of Colorado, Denver.
“We thought smoking made the difference,” Dr. Stuyt said in an interview. “The implication is when getting someone to quit smoking, it is good to know which meds they are on.”
All of the patients–31 with schizophrenia and 24 with schizoaffective disorder–had a cooccurring substance abuse disorder.
Most were referrals to the Circle program, a fully integrated, 90-day inpatient dual-diagnosis treatment program for adults who have failed previous attempts to treat substance dependence. The Colorado Mental Health Institute at Pueblo runs the program.
A majority of the participants are referred as a condition of criminal court (75%–80%); others are referred by civil court (5%–10%), and the rest attend voluntarily (10%–20%).
Fifteen of the 55 study patients took olanzapine (mean dose, 18.78 mg/day), 16 took risperidone (mean dose, 3.9 mg/day), 14 took ziprasidone (mean dose, 132.8 mg/day), and 10 took a typical neuroleptic (5 each took haloperidol decanoate and fluphenazine decanoate).
“We knew there were differences [between medications], but we noticed in our program that people on olanzapine were not doing well,” Dr. Stuyt said. “So we looked retrospectively at psychotic diagnoses at admission, what drug they were on, and the outcome.”
The Circle program uses up to 90 days of cognitive-behavioral treatment. Five objectives are assigned at admission based on existing behaviors. Patients are started at a precontemplative stage regarding their substance abuse, even if they say they are committed to quitting. “They have not demonstrated it by their behavior,” she said.
“It's very hard,” Dr. Stuyt said. “I've had medical students say they don't think they could do it.”
As behaviors improve, participants advance up levels in the program. “They are here to 'gift.' They are not snitches, but they write up reports if they break the rules or they see other people doing something wrong,” she said.
The longer the length of stay, the better the outcome, Dr. Stuyt said. The average length of stay was about the same for risperidone (82 days) and ziprasidone (74 days), but stays were shorter for patients taking olanzapine (44 days) or a typical neuroleptic (47 days).
Participants were considered completers if they completed their homework and strategies for self-improvement, Dr. Stuyt said.
There was a 56% success rate overall: 88% of risperidone patients were completers, versus 64% of ziprasidone and 33% of olanzapine patients, she added.