Colleen Loo, a professor at the University of New South Wales in Australia, led the world’s first randomised control trial into the drug’s effect on people over 60 with treatment-resistant depression.
“This trial has shown ketamine can be used safely in the elderly and it tends to be effective,” she told The Independent, adding that a similar effect was observed in this age group as in younger patients.
It is important to test how people of different ages respond to a new treatment before it can be offered by doctors, she said: “Sometimes depression in the elderly can be harder to treat, especially with medication.
“Also, they tend to have more medical problems, which can interfere with medication.”
Of the study’s 16 participants, 11 reported an improvement in their condition while being treated with the drug, according to the research published in the American Journal of Geriatric Psychiatry.
After six months, 43 per cent of the subjects said they had no significant symptoms of depression – a high rate given that the participants had not responded to previous treatment, said Professor Loo.
“It is truly remarkable the way ketamine can work,” she said. “Other people have also found you get a rapid and powerful effect after a single dose of ketamine.”
“Some people mistakenly think we are inducing a temporary, drug-induced euphoria and people are ‘out of it’, which is why they’re not depressed.
“But the effects take place in the first hour, and they’re not euphoric at all. In fact, all of our research participants disliked them. They considered them adverse effects.
“The antidepressant effect kicks in a few hours later and are maximised about 20 hours later, when you’re fully alert and in your usual state of mind.”
While research into the use of ketamine to treat mental health problems is still in its early stages, scientists at Oxford University have said their studies show the drug can provide relief to patients with severe depression “where nothing has helped before”.
Rupert McShane, the consultant psychiatrist who is leading Oxford’s ketamine treatment programme, told The Independent it was “good to see that, contrary to some reports, some older people do respond to ketamine.”
“This study highlights that ketamine can be given in a variety of ways (not just intravenous), that it’s a good idea to adjust the dose, and that the more resistant someone’s depression is, the higher the dose that they are likely to need,” he said.
Professor Loo and her colleagues delivered ketamine to the patients using a small injection under the skin – similar to the insulin jabs given to diabetes patients.
This makes the drug easier and quicker to administer than the intravenous infusions used in other trials, which require a machine pump to regulate the dose and takes up to an hour to complete.
Participants received increasing doses of ketamine over a period of five weeks, with the dose personalised for each patient.
However, she warned that while the research is one step closer to providing a model for how doctors could prescribe ketamine as a treatment for depression in future, it would still be “premature to jump into clinical practice”.
“There are ‘super-responders’, who after a single treatment can be well for several months,” said Professor Loo, giving the example of a subject who, in 2014, remained free of depressive symptoms for five months after just one dose of ketamine.
But “most people are well but then they relapse over around three to seven days,” she said. “That’s where repeated dosing comes in.”
Ketamine Injections May Help Older Adults With Depression
Repeated subcutaneous injections of ketamine significantly improved symptoms in a small group of older adults with treatment-resistant depression, researchers found in a pilot study published online in The American Journal of Geriatric Psychiatry.
The randomized controlled trial is the first to assess the efficacy and safety of ketamine in the geriatric patient population.
“These findings take us a big step forward as we begin to fully understand the potential and limitations of ketamine’s antidepressant qualities,” said lead author Colleen Loo, MD, a professor in the School of Psychiatry at the University of New South Wales, Sydney, Australia.
Psychiatrists Issue ‘Much-needed’ Consensus on Ketamine for Mood Disorders
“Not only was ketamine well-tolerated by participants, with none experiencing severe or problematic side effects, but giving the treatment by a simple subcutaneous injection (a small injection under the skin) was also shown to be an acceptable method for administering the drug in a safe and effective way.”
Overall, the response and remission rate for older adults receiving ketamine was 68.8%.
Australian researchers tested individualized dosing of ketamine using a dose-titration method in 16 adults age 60 and older. Participants received increasing doses over 5 weeks. The double-blind, placebo-controlled trial included 1 session in which participants received an active treatment substitute that, similar to ketamine, caused sedation.
Why Not Make Ketamine a First-line Treatment?
After the randomized controlled trial, participants received 12 ketamine doses in an open-label phase.
At a 6-month follow-up, 7 of 14 older adults who had completed the randomized controlled trial had depression remission — 5 of whom remitted at doses below the common ketamine dose of 0.5 mg/kg, researchers reported. Repeated treatments, they added, resulted in a higher likelihood of remission or a longer time to relapse.
“Elderly patients with severe depression face additional barriers when seeking treatment for the condition. Many medications may cause more side effects or have lower efficacy as the brain ages,” said researcher Duncan George, MBBS, School of Psychiatry, University of New South Wales. “Older people are also more likely to have comorbidities like neurodegenerative disorders and chronic pain, which can cause further complications due to ketamine’s reported side effects.
“Our results indicate a dose-titration method may be particularly useful for older patients, as the best dose was selected for each individual person to maximize ketamine’s benefits while minimizing its adverse side effects.”
George D, Gálvez V, Martin D, et al. Pilot randomized controlled trial of titrated subcutaneous ketamine in older patients with treatment-resistant depression. The American Journal of Geriatric Psychiatry. 2017 June 13;[Epub ahead of print].
World-first ketamine trial shows promise for geriatric depression [press release]. Sydney, Australia: University of New South Wales; July 24, 2017.
Poster Number: EI 5
Ketamine in Late Life Treatment-Resistant Depression
Erika Heard, MD1
; Yousuf Sohail, MD1
; Anusuiya Nagar, MD1
; Oliver M. Glass, MD2
; Adriana P. Hermida, MD1
Introduction: Ketamine is a dissociative anesthetic, which provides antagonism on the N-methyl-D-aspartate (NMDA)
receptor. Several studies have demonstrated rapid anti-depressant and anti-suicidal effects from the administration of ketamine
in adult patients but studies in late life patients are lacking. While ketamine may increase sympathetic stimulation and cause
decreased respiratory rate in geriatric patients, it is still nonetheless considered a safe agent. Low-dose intravenous infusion of
ketamine is gaining popularity in the treatment for treatment-resistant depression (TRD) in late life patients. We provide a case
report on a patient in late life who suffered from TRD and was treated with ketamine.
Methods: A case report of the use of intravenous ketamine to treat a geriatric patient with TRD along with a literature review
of the subject.
Results: A 76-year-old female with a history of hypertension and arthritis presented with worsening depressive symptoms for the
past two years. She endorsed neuro-vegetative symptoms of depressed mood, poor appetite, unintentional 25-pound weight loss,
and conflicted feelings about wanting to live. She also reported difficulties with concentration and memory, feelings of
worthlessness, and psychomotor retardation. Her daughter stated she was more vegetative and had a strong desire not to live alone.
QIDS (Quick Inventory of Depressive Symptomatology) baseline was 23. She had previous trials of multiple medications including
paroxetine, fluoxetine, sertraline, escitalopram, buproprion, and venlafaxine. This patient showed poor tolerance to all the
medications and at the time of assessment was taking mirtazapine 7.5 mg and duloxetine 60 mg. Electroconvulsive therapy (ECT)
was recommended; however, the patient was found to be not a good candidate as per anesthesiology due to multiple comorbidities.
As a result, mirtazapine was titrated to 15 mg nightly while duloxentine was continued at 60 mg daily. Patient was started on
intravenous ketamine infusions of 20 mg (0.5 mg/kg) over 40 minutes. Patient tolerated the acute course of ketamine, which was
administered twice per week. Patient and daughter reported clinicial improvement after the first infusion with noticeable
improvement in QIDS (23 to 12) after 6 acute sessions without adverse effects. Improved symptoms included brighter affect,
increased energy, decreased anhedonia, increased daily activity, improved appetite (gained 40lbs), and being more engaged in the
community. Additionally, she began to take care of herself again. She has received 17 ketamine treatments with latest QIDS score of
1. After 6 acute infusion sessions, she was tapered to once per week, then once per 10 days, once per 2 weeks and then to a once
every three week schedule before discontinuing. The patient continued to report improvements. The literature on intravenous
ketamine infusions has shown effectiveness in reducing depressive symptoms in cases of TRD. The patient presented in this study
demonstrates promise of the use of ketamine in late life depression patients. This case also highlights that ketamine can be an
alternative option for elderly patients with TRD who do not qualify for ECT. Within the geriatric population, comorbid medical
conditions and polypharmacy may increase the chance of morbidity and mortality. Ketamine infusions at a low dose must be
monitored closely over a course of time. Therefore, ketamine infusions should only be administered to TRD patients in facilities
where appropriate medical monitoring can occur. Geriatric patients who are given ketamine infusions should be assessed for the
development of dependency, and addiction given its abuse potential. Further research on this novel therapy will yield greater
knowledge of how to best utilize ketamine infusions in geriatric patients.
Conclusions: The literature on intravenous ketamine infusions has shown effectiveness in reducing depressive symptoms in cases of
TRD. Similarly, our patient had a decline in depressive symptoms and a positive outcome. The case highlights that ketamine can be
used as an alternative for the TRD population that may not qualify for ECT. Within the geriatric population, comorbid pathology
and poly-pharmacy increase the chance of morbidity and mortality. Ketamine infusions at a low dose can be a potential treatment if
monitored closely over a course of time. Therefore, ketamine infusions offer a safe and effective alternative option for TRD patients
in psychiatric facilities where close monitoring can occur. Patients on ketamine treatments should be continually monitored for
addiction potential and adverse effects to ketamine infusions, none of which were seen with our current patient. Further research on
this novel therapy will yield greater knowledge of how to best utilize ketamine infusions for the general population and more
specifically for the geriatric subset that encompasses the majority of TRD patients.
Introduction: Ketamine is a glutamate NMDA receptor antagonist and is commonly used as an anesthetic. Low-dose
subanesthetic intravenous ketamine is fairly new and an increasingly popular treatment for treatment-resistant depression
(TRD) in the adult population; however, there is a scarcity of evidence of ketamine’s use among geriatric patients. Previously,
psychotropics and electroconvulsive therapy (ECT) have been used in the geriatric TRD population. Ketamine provides a
possible new treatment modality for those patients concerned with ECT-induced cognitive effects and may also allow for use in
patients with significant cardiovascular co-morbidities, who would likely not quality for ECT.
Methods: We provide a literature review on the use of ketamine for TRD in the geriatric population.
Results: Studies and case series have shown the use of ketamine as a monotherapy and augmented therapy with
electroconvulsive therapy in the adult and geriatric population. Literature supports efficacy with monotherapy and questionable
benefit from augmentative therapy. Dosing ranges from 0.2 mg/kg to 0.5 mg/kg, with evidence showing remittance with
ketamine dosing less than 0.5 mg/kg. Some studies have shown cognitive protection as compared to other TRD treatment
modalities, while the majority of studies have not thoroughly analyzed systemic adverse risk profiles including cognitive and
Conclusions: There is evidence in the literature for the use of intravenous ketamine in the TRD geriatric population. Larger
randomized control trials are needed to provided guidance regarding dosing, cognitive and systemic effects, and treatment
USe of Ketamine in agitated delirium in the ELderly:
Treatment of Behavior Disturbances with Ketamine in a Patient Diagnosed with Major Neurocognitive Disorder
Ketamine has been shown to be beneficial for some
depressed patients, but it is not known whether it could
be beneficial for agitated demented patients who are
Augmentation of response and remission to serial intravenous ketamine in TRD
Background: Ketamine has been showing high efficacy and rapid antidepressant effect. However, studies of ketamine infusion wash subjects out from prior antidepressants, which may be impractical in routine practice. In this study, we determined antidepressant response and remission to six consecutive ketamine infusions while maintaining stable doses of antidepressant regimen. We also examined thetrajectory of response and remission, and the time to relapse among responders.
Methods: TRD subjects had at least 2-month period of stable dose of antidepressants. Subjects completed
six IV infusions of 0.5 mg/kg ketamine over 40 min on a Monday–Wednesday–Friday schedule during a
12-day period participants meeting response criteria were monitored for relapse for 4 weeks
Results: Fourteen subjects were enrolled. Out of twelve subjects who completed all six infusions, eleven(91.6%) achieved response criterion while eight (66.6%) remitted. After the first infusion, only three andone out of twelve subjects responded and remitted, respectively. Four achieved response and sixremitted after 3 or more infusions. Five out of eleven subjects remain in response status throughout the 4weeks of follow-up. The mean time for six subjects who relapsed was 16 days.Limitations: Small sample and lack of a placebo group limits the interpretation of efficacy.
Conclusions: Safety and efficacy of repeated ketamine infusions were attained without medication-free state in patients with TRD. Repeated infusions achieved superior antidepressant outcomes as compared to a single infusion with different trajectories of response and remission. Future studies are needed to elucidate neural circuits involved in treatment response to ketamine.
Why Treat Depression besides feeling better? It is associated with increased risk of DEATH:
Adults with mood disorders like anxiety and depression may be more likely to have a heart attack or stroke than people without mental illness, a new study suggests.
Researchers enrolled 221,677 people age 45 and older without any history of heart attack or stroke and tracked them for an average of nearly five years.
More than 90% of participants were ages 45 to 79. In this age group, compared to men without mental health issues at the start, men with moderate psychological distress were 28% more likely to have a heart attack during the study and 20% more likely to have a stroke. Men in this age group with high levels of distress were 60% more likely to have a heart attack and 44% more likely to have a stroke.
Women ages 45 to 79 with moderate psychological problems were 12% more likely to have a heart attack and 28% more likely to have a stroke than women without any mental distress. Women with high psychological distress were 24% more likely to have a heart attack and 68% more likely to have a stroke.
“The stronger association between psychological distress and heart attack in men compared to women could be due to women being more likely than men to seek primary care for mental and physical health problems, thus partly negating the possible physical effects of mental health problems,” said lead study author Caroline Jackson of the University of Edinburgh in the U.K.
“Alternatively, it could reflect the known hormonal protection against heart disease in women since the study population included a large number of younger women,” Jackson said by email. “We did however find a strong association between psychological distress and stroke in women, perhaps suggesting different mechanisms exist between psychological distress and different types of cardiovascular disease in women.”
Overall, the study participants suffered 4,573 heart attacks and 2,421 strokes.
The study wasn’t designed to prove whether or how depression or anxiety might directly cause heart attacks or strokes, researchers note in Circulation: Cardiovascular Quality Outcomes.
Another limitation is that researchers assessed psychological factors at a single point in time, making it impossible to know if worsening cardiovascular health contributed to mood disorders or if mental illness caused heart problems.
However, it’s possible that lifestyle factors like poor eating and exercise habits, smoking, or inactivity might independently influence both the risk of mental health problems and heart issues, the study authors note.
“It is also possible that symptoms of depression or anxiety directly affect the body’s physiology through mechanisms such as hormonal pathways, inflammatory processes in arteries and increased risk of blood clotting,” Jackson said. “It is vital that further research seeks to identify the underlying mechanisms so that we can better understand the link between mental health and subsequent physical health and inform intervention strategies.”
Researchers assessed psychological distress using a standard set of questions designed to reveal symptoms of mood disorders. The questions asked, for example, how often people felt tired for no reason, how often they felt restless or fidgety, and how frequently they felt so sad that nothing could cheer them up.
Overall, about 16% of the study participants had moderate psychological distress and roughly 7% had high or very high levels of mental distress.
SOURCE: http://bit.ly/2PfAJjd Psychological Distress and Risk of Myocardial Infarction and Stroke in the 45 and Up Study
Psychological Distress and Risk of MI and stroke in the 45 and up study
Circulation: Cardiovascular Quality and Outcomes 2018.
Psychological distress, physical illness, and risk of coronary heart disease 2005
Weightlifting and muscle training significantly reduced depressive symptoms among adults regardless of their age and health status, the amount of training, and whether they grew stronger, researchers found in a meta-analysis.
The study, published online in JAMA Psychiatry, spanned 33 randomized clinical trials with more than 1800 participants.
The best improvement appeared to be in participants with mild or moderate depression, suggesting resistance training could be an alternative or add-on treatment option.
Trivia: How Much Exercise Is Needed to Prevent Depression?
“For general feelings of depression and the beginning phases of major depression, antidepressants and medications may not be very effective. There also is a shift toward finding options that do not require someone to start a drug regimen they may be on for the rest of their lives,” said researcher Jacob Meyer, PhD, assistant professor of kinesiology at Iowa State University in Ames.
“Understanding that resistance training appears to have similar benefits to aerobic exercise may help those wading through daunting traditional medication treatment options.”
The meta-analysis did identify smaller reductions in depressive symptoms in randomized clinical trials with blinded allocation or assessment. Better quality trials that compare resistance training with other proven treatments for depression are needed, researchers advised.
Gordon BR, McDowell CP, Hallgren M, Meyer JD, Lyons M, Herring MP. Association of efficacy of resistance exercise training with depressive symptoms. JAMA Psychiatry. 2018 May 9;[Epub ahead of print].
Motivation to move may start with being mindful [press release]. Ames, Iowa: Iowa State University; May 14, 2018.
Resistance exercise training may reduce symptoms of depression. Psychiatric News Alert. May 15, 2018.
Neurologic Changes and Depression
The assessment of late-life depression with comorbid cognitive impairment can be challenging and requires a clear clinical history and a thorough medical and cognitive assessment.
There are several neuropsychological changes associated with late-life depression, ranging from subjective cognitive complaints to mild cognitive impairment to dementia.
Changes on neuroimaging and in several biomarkers (eg, apolipoprotein E e4 allele, beta amyloid, tau, neurotrophins, and so forth) have been associated with late-life depression.
Multiple psychotherapeutic techniques have been found effective in the treatment of late life depression as well as holistic/nontraditional, pharmacologic, and brain-stimulation
Why Does Ketamine Work?
Ketamine and Ketamine Metabolite Pharmacology Insights into Therapeutic Mechanisms.
Ketamine, a racemic mixture consisting of (S)- and (R)-ketamine, has been in clinical use since 1970. Although best characterized for its dissociative anesthetic properties, ketamine also exerts analgesic, anti-inflammatory, and antidepressant actions. We provide a comprehensive review of these therapeutic uses, emphasizing drug dose, route of administration, and the time course of these effects. Dissociative, psychotomimetic, cognitive, and peripheral side effects associated with short-term or prolonged exposure, as well as recreational ketamine use, are also discussed. We further describe ketamine’s pharmacokinetics, including its rapid and extensive metabolism to norketamine, dehydronorketamine, hydroxyketamine, and hydroxynorketamine (HNK) metabolites. Whereas the anesthetic and analgesic properties of ketamine are generally attributed to direct ketamine-induced inhibition of N-methyl-D-aspartate receptors, other putative lower-affinity pharmacological targets of ketamine include, but are not limited to, γ-amynobutyric acid (GABA), dopamine, serotonin, sigma, opioid, and cholinergic receptors, as well as voltage-gated sodium and hyperpolarization-activated cyclic nucleotide-gated channels. We examine the evidence supporting the relevance of these targets of ketamine and its metabolites to the clinical effects of the drug. Ketamine metabolites may have broader clinical relevance than was previously considered, given that HNK metabolites have antidepressant efficacy in preclinical studies. Overall, pharmacological target deconvolution of ketamine and its metabolites will provide insight critical to the development of new pharmacotherapies that possess the desirable clinical effects of ketamine, but limit undesirable side effects.
Mechanisms of ketamine action as an antidepressant.
Ketamine administration during a critical period after forced ethanol abstinence inhibits the development of time-dependent affective disturbances.
Ketamine administration during a critical period after forced ethanol abstinence inhibits the development of time-dependent affective disturbances
that ketamine prevents the development of affective disturbances
when administered at the onset of forced abstinence, and not
shortly thereafter (2–6 days).Studies suggest that the GluN2B subunit of the N- methyl- Daspartate
(NMDA) receptor participates in regulating affect and in
the antidepressant actions of ketamine [9, 14, 16]. Chronic ethanol
administration and early withdrawal increase expression of
GluN2B in several brain areas, particularly within the central
nucleus of the amygdala and bed nucleus of the stria terminalis
(BNST) , both of which are heavily involved in regulating affect
[18–21]. Previously, we found that knockdown of GluN2B-within
the BNST produces antidepressant-like actions similar to ketamine
 and that GluN2B is necessary for long-term potentiation (LTP) within the BNST . Furthermore, we have previously shown that
non-contingent chronic intermittent ethanol enhances LTP within
the BNST which is dependent on the GluN2B subunit .
However, no studies have looked at LTP within the BNST during
withdrawal after contingent 2-bottle choice ethanol drinking. Here
we show that withdrawal from 2BC ethanol drinking decreases the
early component of LTP within the BNST. Further, administration
of ketamine at the onset of forced abstinence, but not shortly
thereafter (2–6 days) facilitated later LTP induction.
Ketamine administered at the onset of
abstinence, but not 6 days later rescued the STP deficit and overall increased the capacity for plasticity within the BNST. Our results suggest, for the first time to our knowledge, that ketamine may need to be administered at a specific time point during abstinence in order to effectively treat and manage alcohol use dependent affective disturbances. These data thus suggest a “critical period” during which ketamine is effective in preventing the development of alcohol abstinence induced affective
Ketamine and MAG Lipase Inhibitor-Dependent Reversal of Evolving Depressive-Like Behavior During Forced Abstinence From Alcohol Drinking
Introduction: Ketamine has emerged as a safe and effective treatment option for treatment refractory depression (TRD) and
suicidal ideation. Electroconvulsive therapy (ECT) is a well established treatment for refractory depression, but this treatment is often deferred or terminated before response due tolerability or medical concerns.
Methods: We present a case series of TRD patients who were unable to receive ECT and offered intravenous ketamine at a dose
of 0.5 mg/kg infused over the course of forty minutes for up 3 treatment sessions within two weeks. Most of these patients
were hospitalized older patients with sufficient medical conditions that increased ECT risks.
Results: Ketamine appears to be a safe and effective alternative for these patients, leading to resolution of suicidality, adherence
to antidepressant treatment, and prompt hospital discharge.
Conclusions: In conclusion, for TRD patients unable to undergo ECT, availability of intravenous ketamine, as an adjunct to
an ECT service, can not only avert the prospect of a prolonged and costly course of hospitalization, but also quickly improve
patients’ quality of life.
Why magnesium is important in treating depression:
Magnesium for treatment-resistant depression A review and hypothesis
Sixty percent of cases of clinical depression are considered to be treatment-resistant depression (TRD). Magnesium-deficiency causes N-methyl-D-aspartate (NMDA) coupled calcium channels to be biased towards opening, causing neuronal injury and neurological dysfunction, which may appear to humans as major depression. Oral administration of magnesium to animals led to anti-depressant-like effects that were comparable to those of strong anti-depressant drugs. Cerebral spinal fluid (CSF) magnesium has been found low in treatment-resistant suicidal depression and in patients that have attempted suicide. Brain magnesium has been found low in TRD using phosphorous nuclear magnetic resonance spectroscopy, an accurate means for measuring brain magnesium. Blood and CSF magnesium do not appear well correlated with major depression. Although the first report of magnesium treatment for agitated depression was published in 1921 showing success in 220 out of 250 cases, and there are modern case reports showing rapid terminating of TRD, only a few modern clinical trials were found. A 2008 randomized clinical trial showed that magnesium was as effective as the tricyclic anti-depressant imipramine in treating depression in diabetics and without any of the side effects of imipramine. Intravenous and oral magnesium in specific protocols have been reported to rapidly terminate TRD safely and without side effects. Magnesium has been largely removed from processed foods, potentially harming the brain. Calcium, glutamate and aspartate are common food additives that may worsen affective disorders. We hypothesize that – when taken together – there is more than sufficient evidence to implicate inadequate dietary magnesium as the main cause of TRD, and that physicians should prescribe magnesium for TRD. Since inadequate brain magnesium appears to reduce serotonin levels, and since anti-depressants have been shown to have the action of raising brain magnesium, we further hypothesize that magnesium treatment will be found beneficial for nearly all depressives, not only TRD.
Does oral administration of ketamine accelerate response to treatment in MDD
Altogether, our results suggest that oral ketamine may be considered as suitable adjuvant to sertraline
in relieving depressive symptoms.
Patients received sertraline (150 mg a day). As an adjuvant, they
received either 50 mg/day ketamine or placebo. Formulation of ketamine capsules used in this study is delineated elsewhere. Different doses of oral ketamine have been used in previous studies; a number of studies have used a fixed dose 0.5 mg/kg or 150 mg/day (Irwin et al., 2013; Jafarinia et al., 2016) whereas others titrated the drug in a rangefrom 0.5 mg/kg to 0.7 mg/kg or 25–300 mg/day (Al Shirawi et al., 2017; Hartberg et al., 2017). The frequency of administration also varies from once daily usage to three times a day (Irwin et al., 2013;
Jafarinia et al., 2016). For IV administration, previous trials recommendan injection once every two or three days (Andrade, 2017).
Here, we used ketamine as an adjuvant and thus a fixed low dose was chosen to minimize adverse effects. Sertraline was initiated at 25 mg/day and increased by 25 mg every three days. The maximum dose reached 150 mg. Ketamine prescription started with initial dose ofsertraline and was prescribed at 25 mg twice daily. During the course of the trial, patients were not allowed to participate in psychotherapeutic sessions or receive any other medication, such as other antidepressants, anxiolytics or hypnotics. They were followed for six weeks and were asked to inform their therapist in case they experienced any adverse effects. Vital signs were recorded and physical examination was performed at the screening session and at each of the post-baseline visits. Upon high clinical suspicion for cardiovascular disease, electrocardiogram monitoring was performed and positive findings were excluded.