Assessment of the abuse liability of buspirone in recreational sedative users.

The abuse potential of buspirone, a new dopaminergic antianxiety drug, was evaluated by assessing its subjective effects in standard (10 mg) and high (40 mg) doses. These were compared with methaqualone (300 mg), diazepam (20 mg and 10 mg), and placebo in 24 casual recreational sedative users. Addiction Research Center Inventory scales measuring euphoria, sedation, dysphoria, and abuse liability were used as dependent measures. Groups of subjects received all treatments in randomized order in six weekly 4-hour sessions. Compared to placebo, methaqualone caused elevated scores on euphoria, physical sedation, and abuse liability scales compared to placebo, while 40 mg buspirone caused increased physical sedation, increased physical and mental dysphoria, and lower abuse liability scores. Overall, buspirone at 40 mg appeared unlikely to be reinforcing to recreational illicit drug users; the 10 mg dose was not discriminable from placebo or 10 mg diazepam. Diazepam at 20 mg showed some euphoriant effect compared to placebo.