Ketamine for Anxiety Disorders: What the Research Says

By Kyle Roth, FNP-BC, APRN, MSN, MHA | Roth Family Medicine and Mental Health | Pocatello, Idaho

When most people hear "ketamine therapy," they think of depression — specifically, treatment-resistant depression that hasn't responded to conventional antidepressants. And that's fair: ketamine's evidence base for depression is the strongest and most well-established.

But the story doesn't end there. A growing body of research suggests that ketamine may be a powerful intervention for anxiety disorders as well — including generalized anxiety disorder (GAD), social anxiety disorder, and PTSD. For the millions of Americans whose anxiety hasn't responded adequately to standard treatments, this is significant news.

Anxiety disorders are the most common mental health conditions in the United States, affecting approximately 40 million adults. First-line treatments — SSRIs, SNRIs, cognitive behavioral therapy — help many people. But a substantial minority don't achieve adequate relief.

Studies suggest that:

• Up to 40% of patients with GAD don't achieve remission with first-line pharmacotherapy
• Social anxiety disorder has particularly high rates of treatment resistance
• PTSD responds to first-line treatments in only about 50–60% of cases
• Many patients who do respond experience only partial improvement, with significant residual symptoms

For these individuals, the question of what comes next is urgent and often unanswered.

Most conventional anxiety medications work on the serotonin or GABA systems. SSRIs and SNRIs modulate serotonin (and norepinephrine); benzodiazepines enhance GABA activity. These mechanisms are effective for many people, but they don't address the underlying neural circuitry that drives pathological anxiety.

Ketamine works primarily through the glutamate system — specifically by blocking NMDA receptors and triggering a cascade of downstream effects that include:

Rapid synaptogenesis. Ketamine promotes the growth of new synaptic connections in the prefrontal cortex and other brain regions involved in emotional regulation. This "rewiring" effect may help break the rigid, fear-based neural patterns that characterize anxiety disorders.

AMPA receptor activation. The downstream effects of NMDA blockade include activation of AMPA receptors, which are involved in synaptic plasticity and mood regulation.

BDNF release. Ketamine triggers release of Brain-Derived Neurotrophic Factor (BDNF), a protein that supports neuronal health and plasticity. Low BDNF levels are associated with both depression and anxiety.

Reduced default mode network activity. Anxiety is often characterized by excessive rumination and self-referential thinking — driven in part by overactivity in the brain's default mode network. Ketamine appears to reduce this overactivity, creating a window of reduced anxiety and increased cognitive flexibility.

Several studies have examined ketamine's effects on anxiety symptoms, often in patients being treated for depression (since the two conditions frequently co-occur). A 2017 study published in Neuropsychopharmacology found that a single IV ketamine infusion produced rapid and significant reductions in anxiety symptoms in patients with treatment-resistant depression and comorbid anxiety.

A more targeted study of patients with GAD found that ketamine produced significant anxiolytic effects within hours of infusion, with effects lasting days to weeks. The rapid onset is particularly notable — conventional anxiolytics either work immediately (benzodiazepines, with their addiction risk) or take weeks to build up (SSRIs). Ketamine offers a third option: rapid relief without the dependence concerns of benzodiazepines.

Social anxiety disorder (SAD) is one of the most common and most undertreated anxiety disorders. A 2017 randomized controlled trial published in Neuropsychopharmacology specifically examined ketamine for SAD and found significant reductions in social anxiety symptoms compared to placebo, with effects persisting for two weeks after a single infusion.

The mechanism may be particularly relevant for SAD: ketamine's ability to reduce fear-based neural patterns and promote cognitive flexibility could help disrupt the automatic threat-appraisal processes that drive social anxiety.

PTSD represents one of the most compelling potential applications for ketamine. The condition is characterized by intrusive memories, hyperarousal, avoidance, and negative alterations in cognition and mood — all of which involve dysregulated fear circuitry and impaired extinction learning.

A landmark 2014 study by Feder et al. found that a single IV ketamine infusion produced rapid, significant reductions in PTSD symptom severity compared to midazolam (an active control). Effects were evident within 24 hours and lasted approximately two weeks.

Subsequent research has explored repeated ketamine infusions for PTSD, with promising results. A 2021 randomized controlled trial found that six ketamine infusions over two weeks produced significantly greater PTSD symptom reduction than six midazolam infusions, with effects maintained at follow-up.

The mechanism is thought to involve ketamine's ability to facilitate fear extinction — essentially helping the brain "unlearn" the conditioned fear responses that drive PTSD symptoms. This has led to interest in combining ketamine with trauma-focused psychotherapy, using the post-infusion window of neuroplasticity to enhance therapeutic processing.

Obsessive-compulsive disorder (OCD) has also been studied in the context of ketamine. A small but intriguing study found that a single ketamine infusion produced rapid reductions in OCD symptoms, with effects lasting days to weeks. The glutamate system's role in OCD — a condition increasingly understood as involving cortico-striato-thalamo-cortical circuit dysfunction — makes ketamine a theoretically compelling option.

Ketamine for anxiety is most appropriate for patients who:

• Have not achieved adequate relief from two or more first-line treatments (SSRIs, SNRIs, therapy)
• Have significant functional impairment from anxiety symptoms
• Have comorbid depression (ketamine addresses both simultaneously)
• Need rapid relief — for example, in acute crisis situations
• Have PTSD and are interested in combining ketamine with trauma-focused therapy

It is generally not the first treatment tried for anxiety — conventional options should be explored first. But for patients who have exhausted standard approaches, ketamine represents a genuinely different mechanism with real evidence behind it.

At Roth Family Medicine and Mental Health, we offer ketamine-assisted therapy for both depression and anxiety disorders. Our protocol includes:

Comprehensive evaluation — We conduct a thorough assessment of your anxiety history, prior treatments, medical history, and current medications before recommending ketamine.

Personalized treatment planning — The number of infusions, dosing, and integration support are tailored to your specific situation.

Safe, monitored infusions — All infusions are conducted in a clinical setting with continuous monitoring of vital signs and mental status.

Integration support — The post-infusion period is a window of enhanced neuroplasticity. We provide guidance on how to use this window therapeutically, and can coordinate with your therapist if you're engaged in psychotherapy.

Follow-up care — We monitor your response and adjust the treatment plan as needed.

If you're struggling with anxiety that hasn't responded to conventional treatments, we'd welcome the opportunity to discuss whether ketamine therapy might be appropriate for you.

Kyle Roth, FNP-BC, APRN, MSN, MHA is a board-certified family nurse practitioner at Roth Family Medicine and Mental Health in Pocatello, Idaho, specializing in treatment-resistant depression, ketamine therapy, TMS, hormone optimization, and integrative mental health care. To schedule a consultation, visit ZocDoc or call (208) 904-4705.