What would be harmful side effects that a teen could get from taking barbiturates for sleep?

Barbiturates: A barbiturate gives feelings of euphoria and relaxed contentment, thus helping with sleep. The main risks of barbiturate use is respiratory depression. Psychological and physical dependence may also develop with repeated use. Other effects of barbiturate overuse or intoxication include ataxia, drowsiness, vertical and lateral eye twitching, slurred speech, decreased anxiety and loss of inhibition.