Psychiatry and Behavioral Medicine
Core concepts
Major depression requires five or more symptoms for at least two weeks, including depressed mood or anhedonia. Before starting an antidepressant, screen for bipolar disorder: treating bipolar depression with an antidepressant alone can trigger mania or rapid cycling. A manic episode requires elevated or irritable mood with increased energy lasting at least a week, with decreased need for sleep, grandiosity, pressured speech, and risky behavior.
Serotonin syndrome and neuroleptic malignant syndrome are frequently confused. Serotonin syndrome begins within hours, with agitation, clonus, hyperreflexia, and hyperthermia; stop the offending agents and consider cyproheptadine. Neuroleptic malignant syndrome evolves over days with lead-pipe rigidity, hyperthermia, autonomic instability, elevated creatine kinase, and leukocytosis; stop the antipsychotic and treat with dantrolene or bromocriptine.
Substance use: alcohol withdrawal tremor appears at 6 to 24 hours, seizures at 12 to 48 hours, and delirium tremens at 48 to 96 hours; treat with benzodiazepines and give thiamine before glucose. Opioid overdose shows pinpoint pupils and respiratory depression, reversed with naloxone.
Eating disorders carry the highest mortality in psychiatry; anorexia nervosa produces bradycardia, hypothermia, and refeeding risk.
Traps
- Prescribing an SSRI without asking about prior manic episodes.
- Calling every rigid febrile patient serotonin syndrome; look at onset and reflexes.
- Ignoring suicide risk assessment in a patient who appears calm after starting treatment.
Rule of thumb
Fast onset, clonus, and hyperreflexia point to serotonin syndrome; slow onset, lead-pipe rigidity, and a high creatine kinase point to neuroleptic malignant syndrome.