Who May Be a Candidate for Ketamine Therapy?
Ketamine therapy isn’t appropriate for everyone, and reputable providers invest significant time in evaluating candidacy before starting treatment. Understanding the general criteria that guide these decisions can help patients and caregivers approach the process with realistic expectations and know what kinds of questions and history a thorough evaluation should cover.
The General Profile: Treatment-Resistant Depression
As discussed in detail in an earlier article in this series, the best-established candidacy criteria exist for ketamine and esketamine treatment of depression, specifically treatment-resistant depression — depression that has not adequately responded to at least two different antidepressant medications, given at adequate doses for an adequate duration. This is the population specifically studied in esketamine’s FDA-approval clinical trials, and it’s the population most consistently discussed in the broader research literature on IV ketamine for depression as well.
Within this general category, providers typically look for:
**A confirmed diagnosis of major depressive disorder**, established through a thorough psychiatric evaluation, rather than self-reported low mood alone.
**A documented history of prior treatment attempts**, including which medications were tried, at what doses, for how long, and what the outcome was — since this history is what actually establishes whether the treatment-resistant criteria are met.
**Age within the studied range.** Esketamine’s FDA approval is specifically for adults; ketamine’s use in adolescents or children for psychiatric indications remains a much less studied area and is generally approached with additional caution.
## Depression With Suicidal Ideation
As discussed in an earlier article, esketamine also carries a specific FDA approval for adults with major depressive disorder who are experiencing suicidal ideation or behavior. This represents a distinct, high-risk population for whom the rapid onset of ketamine-based treatment may offer particular clinical value, given the urgency of the situation, though it also requires especially close psychiatric monitoring given the complexity and severity of what these patients are experiencing.
Chronic Pain Candidates
For chronic pain conditions, discussed in detail in an earlier article in this series, candidacy typically centers on patients with conditions like complex regional pain syndrome or certain other forms of neuropathic pain who have not achieved adequate relief through more established, first-line pain management approaches. As with depression, a documented history of prior treatments and their outcomes is typically an important part of the evaluation.
Factors That Support Candidacy
Beyond the core diagnostic criteria, several additional factors are generally viewed favorably during a candidacy evaluation:
**Stable cardiovascular health**, given ketamine’s effects on blood pressure and heart rate, discussed in the companion article on side effects and risks.
**No personal history of psychosis**, given the pharmacological relevance of NMDA receptor modulation to psychotic symptoms, discussed further in the article on who should avoid ketamine.
**No active, uncontrolled substance use disorder**, given ketamine’s own potential for misuse and dependence.
**Realistic expectations and willingness to engage in a full treatment course**, since, as discussed in the article on duration of effects, ketamine is generally most effective as part of a structured series of treatments and ongoing maintenance, rather than a single session expected to produce permanent results.
**Willingness to continue other aspects of psychiatric care**, since esketamine specifically is approved for use alongside an oral antidepressant, and many providers view ketamine treatment generally as most effective when integrated with ongoing psychiatric care and, often, psychotherapy, rather than used as a stand-alone intervention.
The Role of a Thorough Evaluation
A legitimate candidacy evaluation typically involves several components, and patients should expect a reputable provider to take this process seriously rather than treating it as a formality:
**Psychiatric history and current symptom assessment**, often using standardized depression or anxiety rating scales to establish a baseline against which future progress can be measured.
**Detailed medication history**, including specific dosages and durations of prior antidepressant trials, to confirm treatment-resistant criteria are genuinely met.
**Medical history and physical health screening**, including blood pressure, cardiovascular history, and any other conditions that might affect candidacy or require special precautions.
**Substance use history**, given both the relevance of active substance use disorders to candidacy and ketamine’s own potential for misuse.
**Discussion of expectations and treatment goals**, ensuring the patient has a realistic understanding of what the treatment can and cannot be expected to achieve, and what the likely treatment timeline and course will look like.
What Good Candidacy Doesn’t Mean
It’s worth being clear that meeting general candidacy criteria doesn’t guarantee that ketamine treatment will be effective for a given individual — as discussed in earlier articles in this series, response varies considerably between patients, and current research hasn’t identified reliable ways to predict in advance who will respond well. Candidacy criteria are about identifying patients for whom the treatment is a reasonable, appropriately considered option given the evidence and risk profile — not a guarantee of a particular outcome.
It’s also worth noting that candidacy isn’t a one-time, static determination. A patient’s overall health, medication regimen, or life circumstances can change over time, and reputable providers generally reassess relevant factors on an ongoing basis throughout a course of treatment, rather than making a single determination at intake and never revisiting it.
A Note on Off-Label Flexibility
Because much of ketamine’s use for depression and pain occurs off-label, individual physicians have some latitude in how strictly they apply criteria like the treatment-resistant depression definition, based on their own clinical judgment for a particular patient’s situation. This is a normal part of medical practice, but it also means that candidacy standards can vary somewhat between providers, which is one more reason that choosing an experienced, reputable provider — discussed in more detail in a dedicated article later in this series — matters so much.
Questions Patients Can Ask During an Evaluation
– What specifically about my history and diagnosis makes me a reasonable candidate for this treatment?
– Are there any factors in my medical or psychiatric history that give you pause, and how would those be managed?
– What outcome measures will we use to track whether this treatment is actually working for me?
– What would cause you to recommend stopping or adjusting this treatment plan?
The Bottom Line
Good candidacy for ketamine or esketamine therapy generally centers on a confirmed diagnosis (most commonly treatment-resistant depression or certain chronic pain conditions), a documented history of prior treatment attempts, reasonably stable physical and psychiatric health, and realistic expectations about the treatment process. A thorough, honest evaluation — not a quick screening questionnaire — is the hallmark of a responsible provider, and patients should feel empowered to ask detailed questions about why they are or aren’t considered a good candidate for this particular treatment.
*This article is for educational purposes only and does not constitute medical advice or a candidacy assessment. Only a licensed healthcare provider, after a thorough individual evaluation, can determine whether ketamine or esketamine therapy is appropriate for a specific person.*