Primary sources we use
National Institute of Mental Health (NIMH). The U.S. federal agency for mental health research. Topic pages on depression, suicide prevention, and clinical trials. nimh.nih.gov.
Substance Abuse and Mental Health Services Administration (SAMHSA). The U.S. federal agency for behavioral health services. Treatment locator, crisis services, and policy. samhsa.gov.
American Psychiatric Association (APA). The U.S. professional association of psychiatrists. Publishes the DSM-5-TR and the current Practice Guideline for the Treatment of Patients with Major Depressive Disorder. psychiatry.org.
National Institute for Health and Care Excellence (NICE). The clinical guidance body of the U.K. National Health Service. NICE guideline NG222 on depression in adults is one of the most thorough public treatment guidelines available. nice.org.uk.
World Health Organization (WHO). Publishes the ICD-11 and the mhGAP intervention guide. who.int.
Centers for Disease Control and Prevention (CDC). U.S. public health agency. Suicide prevention data, surveillance, and resources. cdc.gov.
U.S. Preventive Services Task Force (USPSTF). Evidence-based recommendations on screening, including depression screening in adults and adolescents. uspreventiveservicestaskforce.org.
The Cochrane Library. Independent systematic reviews of clinical interventions. The strongest single source for "does this treatment work, and by how much." cochranelibrary.com.
PubMed. The U.S. National Library of Medicine database of peer-reviewed biomedical literature. We use PubMed for primary studies. pubmed.ncbi.nlm.nih.gov.
U.S. Food and Drug Administration (FDA). The U.S. agency that regulates medications and devices. We cite the FDA for boxed warnings, prescribing information, drug approvals, and Risk Evaluation and Mitigation Strategies (REMS) for products like esketamine. fda.gov.
U.S. Drug Enforcement Administration (DEA). The federal agency that regulates controlled substances and telemedicine prescribing under the Ryan Haight Act. We cite the DEA for current rules on remote prescribing of stimulants, benzodiazepines, and other scheduled medications. dea.gov.
American College of Obstetricians and Gynecologists (ACOG). The U.S. professional society for obstetricians and gynecologists. We cite ACOG Committee Opinions and Practice Bulletins for perinatal mental health, including screening and treatment of depression in pregnancy and postpartum. acog.org.
How we weigh evidence
Not every source carries the same weight. When two sources disagree, the page leans on the higher-tier source and notes the disagreement. The rough order, strongest to weakest, is:
- Systematic reviews and meta-analyses of randomized trials (Cochrane, peer-reviewed meta-analyses in major journals). The strongest evidence for whether a treatment works and roughly by how much.
- Current clinical practice guidelines from recognized bodies (APA, NICE, USPSTF, ACOG, AACAP, WHO). These already weigh the underlying trials and add expert consensus.
- Individual randomized controlled trials, especially large, pre-registered, multi-site trials with a clinically meaningful comparator.
- Prospective cohort and registry studies, used where randomization isn't feasible (long-term safety, rare outcomes, real-world effectiveness).
- Regulatory documents (FDA labeling, REMS, boxed warnings; DEA scheduling and Ryan Haight Act guidance) for what's currently approved, restricted, or required.
- Expert opinion and clinical experience, used only where higher-tier evidence is absent and clearly labeled as such on the page.
Evidence evolves. Guidelines are revised, new trials change effect estimates, and FDA labeling is updated. Every clinical page on this site carries a last-reviewed date so you can see how current the evidence on that page is. When a meaningful change happens between scheduled reviews (a new boxed warning, a major guideline update), we update the page out of cycle and update the date.
How to read a source
Source pages are dense. A short guide to reading them.
A guideline (APA, NICE, WHO) tells you what a professional body recommends as standard care. It's built from multiple studies and expert review.
A systematic review (Cochrane, others) tells you what the existing studies, taken together, suggest. It's usually the strongest evidence for any single question.
A primary study (in PubMed) tells you what one group of researchers found in one trial. It needs context.
A topic page from NIMH, SAMHSA, CDC, or the APA tells you the public-facing summary, written for non-clinicians.
Reference style on this site
Articles on this site link source organizations and, where possible, individual citations directly. We use plain English in the body of the page and put the sources at the bottom. Where a specific study or guideline is the basis of a claim, we name it in the source list at the end of that page.
Where to start if you want one source to read
For a single readable starting point, the NIMH Depression topic page is the most accessible. For depth, the NICE depression guideline NG222 is the most thorough public document on treatment we can recommend.