Overview of psychiatric medication classes
Psychiatric medications don't fix a "chemical imbalance" in any simple sense — the serotonin hypothesis of depression has been substantially revised. They do reliably change neurological functioning in ways that reduce symptoms for many people. Understanding what different medication classes do helps you have informed conversations with your prescriber.
Antidepressants
SSRIs (selective serotonin reuptake inhibitors) — including sertraline, fluoxetine, and escitalopram — are first-line for depression and anxiety. SNRIs (duloxetine, venlafaxine) have similar evidence with additional norepinephrine effects. Both typically require 4-6 weeks to see full effect. Bupropion has a different mechanism and is particularly useful for depression with fatigue and for smoking cessation. Tricyclics and MAOIs are older classes with more side effects, used when others have failed.
Mood stabilizers
Lithium has the strongest evidence base for bipolar disorder and is the only medication shown to reduce suicide risk. Valproate, lamotrigine, and carbamazepine are anticonvulsants also used as mood stabilizers. Each has a different profile of efficacy for mania vs depression vs maintenance.
Antipsychotics
First-generation antipsychotics (haloperidol, chlorpromazine) are effective but have significant movement disorder side effects. Second-generation antipsychotics (quetiapine, aripiprazole, risperidone) are more commonly used and have different side effect profiles. They are used for schizophrenia, bipolar disorder, and sometimes augmentation of antidepressants.
Starting, stopping, or changing psychiatric medications should always be done in coordination with your prescriber. Never stop psychiatric medications abruptly — many require gradual tapering. If you are having side effects or feel the medication isn't working, contact your prescriber rather than stopping on your own.