Ketamine, a derivative of phencyclidine, has anesthetic, analgesic, and antidepressant properties but is also a new psychoactive substance with psychedelic effects. Its recreational use has grown globally, becoming a common club drug that threatens public health by causing physical and psychiatric harm. Concurrent or sequential use with other drugs worsens health consequences. There are no specific treatments for compulsive drug-seeking in ketamine use disorder, and pharmacotherapy for side effects is limited and symptomatic. This chapter covers ketamine abuse history, proposes neural disinhibition mechanisms underlying addiction, details negative effects of long-term and recreational use on central and peripheral systems, and reviews adverse interactions from concomitant use.
Dextromethorphan (DXM), a common cough suppressant that is not a controlled substance in the US, can induce psychosis characterized by disorganized behavior, thinking, and perception. Management of DXM-related psychosis depends on the type of symptoms. Atypical neuroleptics such as olanzapine, risperidone, and quetiapine, as well as typical haloperidol, are used for symptomatic treatment, particularly for positive symptoms like hallucinations and delusions. Atypical antipsychotics are preferred over haloperidol due to their better efficacy and safety profile in the short term. This review summarizes current knowledge on DXM's psychotic potential and the management of DXM-related psychoses, focusing on atypical antipsychotic drugs.