After finishing this chapter, students should be able to understand:
The barbiturates, benzodiazepines, inhalants, and other depressant drugs all have many effects in common with each other and with alcohol.
Depressants may be prescribed in low doses for their sedative effect or in higher doses as sleeping pills (hypnotics).
Over the past forty years the barbiturates have been mostly displaced by the benzodiazepines.
The benzodiazepines are the most widely prescribed type of psychoactive drug.
The barbiturates and benzodiazepines both increase the inhibitory neural effects of the neurotransmitter GABA.
Drugs that have a rapid onset are more likely to produce psychological dependence.
Drugs that have a short duration of action are more likely to produce withdrawal symptoms.
Overdoses of these depressant drugs can cause death by inhibiting respiration, particularly if the drug is taken in combination with alcohol.
The abused inhalants include gaseous anesthetics, certain nitrites, and volatile solvents.
Abuse of inhalants, especially of the volatile solvents, can lead to organ damage, including neurological damage, more readily than with alcohol or other psychoactive substances.
