Model insomnia by methylphenidate and caffeine and use in the evaluation of temazepam

Experimental sleep disturbances (model insomnia) were produced by the administration of methylphenidate (MPD) 10 mg and caffeine (CAF) 150 mg. The effect of temazepam (TEM), 15 mg or 30 mg, on the model was investigated. All-night polysomnography was performed on 8 normal young male subjects under each of the following 9 conditions: baseline, MPD 10 mg, CAF 150 mg, TEM 15 mg, TEM 30 mg, MPD + TEM 15 mg, MPD + TEM 30 mg, CAF + TEM 15 mg, CAF + TEM 30 mg. A reduction in total sleep time and total amount of stage REM (S-REM) sleep and an increase in the sleep latency and wake time (S-W) were observed in both the MPD and CAF nights. The sleep latency was significantly longer in the CAF night than in the MPD night. Administration of TEM 15 mg or TEM 30 mg alone caused very few modifications in the sleep parameters. These drugs in combination with MPD or CAF resulted in almost complete recovery of the sleep disturbance induced by MPD or CAF. The results indicate that CAF and MPD produced similar models of insomnia except for a greater sleep latency for CAF than for MPD. Both models were useful in the evaluation of hypnotic drugs such as temazepam.