<unk>  may be caused by: *A medical condition such as stroke affecting the brainstem *Voluntary breath-holding or underbreathing, for example,<unk>  training or the Buteyko method. *Medication or drugs, typically when taken in accidental or intentional overdose. Opioids and benzodiazepines in particular are known to cause respiratory depression. Examples of opioids include pharmaceuticals such as oxycodone and hydromorphone and examples of benzodiazepines include lorazepam and alprazolam. *Hypocapnia, which stimulates<unk>  *Obesity; see Obesity<unk>  syndrome *Chronic mountain sickness, a mechanism to conserve energy. Medications As a side effect of medicines or recreational drugs,<unk>  may become potentially life-threatening. Many different central nervous system (CNS) depressant drugs such as ethanol, benzodiazepines, barbiturates, GHB, sedatives, and opioids produce respiratory depression when taken in large or excessive doses, or mixed with other depressants. Strong opiates (such as fentanyl, heroin, and morphine), barbiturates, and certain benzodiazepines (short acting ones and alprazolam) are known for depressing respiration. In an overdose, an individual may cease breathing entirely (go into respiratory arrest) which is rapidly fatal without treatment. Opioids, in overdose or combined with other depressants, are notorious for such fatalities.
Hypoventilation
Hyperventilation
Permissive hypercapnia
Hypoxic ventilatory response
Hyperoxia
Pseudohypoxia
Expiratory apnea
Cerebral hypoxia