Ketamine treatment is sometimes used for severe depression, especially when regular antidepressants medicines and therapy have not worked well. It may help some people by acting on different brain pathways involved in affect regulation, and improvement can occur in selected cases faster than with standard antidepressants. Ketamine is usually given under close medical supervision because the dose, monitoring, and patient selection are very important. While some people experience improvement in mood, ketamine treatment is not suitable for everyone. Possible side effects may include dizziness, temporary increase in blood pressure, nausea, confusion, dissociation, sleepiness, or changes in perception during or after treatment. Doctors usually evaluate mental health history, substance use, heart health, anxiety, and suicidal risk before deciding whether this option is appropriate. Psychotherapy, sleep improvement, exercise, stress management and regular psychiatric care remain important parts of depression treatment, even when ketamine is considered. Worsening suicidal thoughts, panic, severe mood changes or loss of daily functioning may require more intensive psychiatric support and monitoring.