Intranasal Insulin for Some Autism vs IGF-1 and NNZ-2566

 

Very often the simplest solutions are the best and very often, when fault finding a problem, people overlook the obvious.  

I seem to be forever having to mend things and I find this all the time.

Back in 2013, when I knew much less about autism, I wrote about the experimental use of insulin like growth factor 1 (IGF-1) in autism.  

It’s a Small World – IGF-1 and NNZ-2566 in Autism

It turned out that in autism the many different growth factors can be disturbed (too much, or too little) and this variation does indeed define some specific types of autism.  For example in Rett Syndrome there are very low levels of Nerve Growth Factor (NGF); low levels of NGF in some older people is the cause of their dementia.  In more common types of autism NGF is actually elevated.

IGF-1 is very well studied.

 

IGF-1 is a primary mediator of the effects of growth hormone (GH). 

Growth hormone is made in the anterior pituitary gland, is released into the blood stream, and then stimulates the liver to produce IGF-1. IGF-1 then stimulates systemic body growth, and has growth-promoting effects on almost every cell in the body, especially skeletal muscle, cartilage, bone, liver,kidney, nerves, skin, hematopoietic cell, and lungs. This would explain why adults abusing GH may end up needing hip and knee replacements.

Before getting into the science, IGF-1 has long been available as a drug to treat children with growth delays.  In the US this drug is being used on children with a type of autism called Phelan-McDermid Syndrome.

Now, regular readers will recall from my last post on intranasal insulin that it was in this very syndrome that there was a successful intranasal insulin.

So most likely without delving into the science at all it looks like IGF-1 and intranasal insulin are both options to treat the same dysfunction.

Using IGF-1

Clinical Trial in 22q13 Deletion Syndrome (Phelan-McDermid Syndrome)

Using Intranasal Insulin

Intranasal insulin to improve developmental delay in children with 22q13 deletion syndrome: an exploratory clinical trial.

NNZ-2566

This is an Australian drug that is a modified version of IGF-1 (a so called analog).  They modified it so that it can be taken orally rather than by injection.  The developer has a very thorough presentation showing why they think it should be effective in autism.  

  

NNZ-2566 - Rationale for use in Autistic Spectrum Disorders

The Science

The first thing to note is that insulin and IGF-1 act as messengers.  Disruption in growth factor signaling can have serious consequences.

Insulin and IGF-1 both activate the same insulin receptor (IR).

Most people think that insulin is a just a hormone produced in their pancreas that regulates the amount of glucose (sugar) in their blood.  It does of course do that, but it actually does much more.

  

Insulin receptors are expressed all over the body including the brain.

Here is a relatively simple presentation explaining the role of insulin signaling in the brain:-

The role of insulin receptor signaling in the brain

Now for the diehard scientists among you that have been reading about all those signaling pathways that lie behind autism, cancer and many other hard to treat conditions, look at the graphic below.

We know the importance of RAS.  Impaired RAS signaling underlies the RASopathies, one feature of which is cognitive loss (MR/ID), another is autism.

We also know the importance of Akt (PKB/protein kinase B) in some types of autism.  PTEN appears again.

So irrespective of an undoubtedly important effect on glucose and insulin resistance, we should expect activation of insulin receptors in the brain, in some types of autism, to have a further positive effect.

It would seem to be a potential therapy for RASopathies.

As is often the case, there are extreme dysfunctions of RAS and I suggest there are more mild dysfunctions.

I suggest that some people with autism and some cognitive dysfunction have a partial RASopathy.

Since autism contains both extremes of many dysfunctions, there will undoubtedly be types of autism that respond negatively, or not at all, to activation of insulin receptors in the brain.

Practicalities

Nobody likes injections and that is necessary to give IGF-1.

NNZ-2566 is an experimental autism drug and on past performance that means it will take decades to reach the market, if ever.

That leaves insulin which was sitting all along in your local pharmacy.

Intranasal insulin was once investigated for use in diabetics, but it did not work.  It is not absorbed into the blood stream.

This is of course the huge advantage for people with autism, since we only want to activate the insulin receptors in the brain.  If you are not diabetic why would you want to have any effects in the rest of the body?

Indeed there are known major side effects of injecting IGF-1 or GH (growth hormone) into adults.  All kinds of things start growing and this can lead to terrible results.

The fact that all the studies show that intranasal insulin does not enter the blood stream and so lower blood glucose levels, makes it a much better drug for autism than IGF-1 or indeed NNZ-2566.

Insulin

There are various types of insulin and the main difference is that some are modified to be longer acting.

The basic insulin is soluble or clear insulin, and nowadays is synthetic rather than derived from pigs.  Examples include Humulin Regular/R/S by Lilly.

The standard concentration is 100 IU/ml.

The trials in Alzheimer’s and other conditions varied in dosage but generally used about 20 to 40 IU per day.

This is not a trivial dose.  If injected, rather than inhaled, that dose would have a significant effect on lowering blood sugar and would be dangerous.

My antihistamine nasal spray gives a metered dose of 0.14 ml.

So without any dilution, if filled with off the shelf insulin it would dispense 14 IU per spray.

So no special high tech drugs, dilutants/diluents or dispensers appear to be necessary. Some trials do use fancy inhalers, like the one in the video at the end of this post.

To be prudent it might be wise to dilute the insulin so as to gradually increase the dose.  Maybe in some people the nasal membrane is more permeable than in others.  Some of the trials did this, but most did not.

A fridge is required, because insulin needs to be kept chilled.

I do wonder why nobody seems to be researching this in autism.  Silly point, as one insulin researcher commented on the earlier post; there is no big money to be made, hence no interest.

Insulin & Alzheimer’s

The reasons that intranasal insulin improves Alzheimer’s, and likely will Down Syndrome, may differ to those help in (some) autism.

Beta amyloid is key to Alzheimer’s (and early onset Alzheimer’s in Down Syndrome) but is not a known issue in autism.  Central insulin resistance is an issue in Alzheimer’s and might well be in autism.  

Perhaps people with mitochondrial dysfunction (an energy conversion dysfunction) might particularly benefit from increased glucose uptake in the brain.  It appears that mitochondrial dysfunction plays a role in insulin resistance. 

Role of Mitochondrial Dysfunction in Insulin Resistance

The activation of the RAS pathway might be highly beneficial to some people with autism.  

Here is a good film, which refers to the studies from previous posts and shows the effect on one man with Alzheimer's. 

Insulin and Alzheimer's (approx. 22 min.)

 You also see their fancy inhaler device.

Interview Series with Leading Autism Researchers

Seth Bittker, a regular reader of this blog and our occasional guest blogger, is creating an excellent interview series with leading autism researchers.

These interviews will be of interest to all readers of this blog.  There is something for everyone, whether you are the type that reads the literature in detail, or is more interested in the lay summary.

There are three interviews, all with podcasts, and more will be added later.

1)    Dr. Richard Frye on folate receptor alpha antibodies and folinic supplementation in autism. 

2)    Dr. Robert Hendrenon his recent double blind placebo controlled trial of methyl-B12 in autism.  

3)    Dr. Derrick Lonsdale on thiamine deficiency and supplementation of thiamine derivatives in autism.   

Good work Seth!  I am sure he will be interested in your suggestions for future interview candidates. 

By the way, in the third interview, Dr Lonsdale refers to his preferred thiamine supplement called TTFD, this has been used for decades in Japan.   It is also called Fursultiamine and the Japanese brand name is Alinamin, which is made by Takeda, a major Japanese company.  The Japanese website (in English) is here.

Takeda have various combinations with other B vitamins and some are sold on Amazon/eBay.  Some with very high amounts of B12.  

In interview number two above, Dr Hendrenon clearly does believe in the merits of extra B12 in autism.  His trial did inject the vitamin, rather than take it orally. 

It is best to only supplement at high doses the B vitamins that really help in your specific case; there are known  negative reactions to some B vitamins, so best to go through them one by one.

There is also a version of TTFD sold as Allithiamine by a small US company, Ecological Formulas, which Seth is investigating.

So as long as swallowing pills is possible, you have the opportunity to replicate Dr Lonsdale's trial and see if you have a responder or not. 


Side Effects of high dose B vitamins

According to the University of Maryland taking any one of the B vitamins for a long period of time can result in an imbalance of other important B vitamins, they suggest taking a B-complex vitamin which includes all B vitamins.

This might explain why some people who initially respond well to high doses of biotin, vitamin B7, later experience a negative response. 

Many people do not respond well to high doses of multiple B vitamins as prescribed by some DAN-type doctors.

Dr Frye, from interview number one, is also a big believer in B vitamin supplementation.

Clearly B vitamin supplementation needs to be much better thought out, to keep any good effects, without developing any bad effects. 

Dad! Can I cheat?

This week at school is a talent show and Monty, aged 12 with ASD, has signed up to play the piano.

Last month was a poetry evening in the senior school, where the older pupils recited poetry in a wide variety of European languages.  Monty did attend to support his big brother and did not do anything to embarrass him.

I think the talent show is more for the juniors, even though it is open to the seniors.

Nine years ago when Monty got his diagnosis, we were given some rather eclectic tips, including he might develop epilepsy and not to expect him to participate in school events.  I always thought the latter was an odd thing to say at the end of your autism assessment, however true it might be.

Nonetheless we have endeavoured to overcome the odds and make sure he does participate in school events.  Monty is the only one with autism in the junior school, while in the senior school there is one with Asperger’s, who proudly recited his poem the other evening.  The school is very good and supports everyone to participate in events.  It is a very small school, which does make things easier.

Talent Show Preparation

The only question with the piano recital is what to play and whether to use the music book or play from memory.

I am surprised that much of the music Monty plays he has actually memorised, but now he plays longer pieces and so the scope for slip ups is greater.

So I asked him to play his latest piece, Phantom of the Keys, from memory and after a couple of minutes he got stuck, picked up the music book turned around and said “Dad! Can I cheat?”

So he won’t be playing from memory.

More General Preconceptions

I think quite often people with autism are held back by preconceived limits on what they can achieve.

Some young adults with autism achieve far more than others and the limiting factor does not seem to be their inherent abilities, much more what they have done in their first twenty years of preparation for life.

Some quite able people with Asperger’s cannot use public transport and, assuming they cannot drive, how are they ever going to have a job? The problem often is anxiety, but in the previous twenty years was it not possible to address that issue?

Monty used to really hate the sound of babies crying.  The effective therapy was to be exposed to that very sound he found excruciating and not to hide him away from it. Now he is perfectly OK with that sound.

The same seems to apply to going to the cinema/theatre, if you start going at a young age you get used to the light and sound.  If you accept sensory overload as barrier, then you may just lower your sights accordingly.

The other day I was talking to a parent of a boy a few years older than Monty and I was really impressed that he goes to his special school alone, by the regular city bus, in the middle of one of Europe’s biggest cities.   He does not get lost, or wander off.  Good for him and you can see him being able to do some kind of adapted job in the future.

Other people develop intellectually, but early problems like toileting are left unaddressed, so you will have adult that cannot care for himself.

Some kind of job, or structured daytime activity, seems a prerequisite for all adults (with, or without autism) but if you cannot get to that job and care for yourself while you are there, you have ruled out that option.

The key does seem to be higher aspirations earlier on, rather than just accepting the many difficulties as immovable barriers.

Outcomes vary widely because each person is an experiment, there is very little sharing of accumulated knowledge.  Basic things like doing some extra school work at home often do not a happen.  In special schools, parents complain that their child cannot do even basic maths or write, while teachers comment “you can always tell which ones get some help at home”. 

The ones that get the help at home are the ones likely to get the extra support at school.

Common sense would suggest that parents must realize that if a child has great learning difficulties and there are six kids to one teacher, not much learning is going to take place at school and, if none takes place at home, the result is not going to be good.

You might think that some learned professional would right an “Autism for Dummies” so that many common mistakes could be avoided.  Such people do indeed exist, who can quickly spot errors that you make, not realizing the eventual long term consequence.

In the ideal world if you receive an autism diagnosis, you would be assigned a mentor who would give you occasional guidance and support through to adulthood. That way more people would achieve their potential.

Mirtazapine and Folate for Idiopathic Schizophrenia, but for which Autism?

 China, where things tend to be big, even their clinical trials

A short while ago we looked at the possible mechanisms behind a reader’s successful experience in use of Mirtazapine (Remeron) in autism, then being prescribed to increase appetite.

Mirtazapine is a tricyclic antidepressant, meaning it is very closely related to first generation antihistamines, but it has numerous other effects;  more of that later.

Folate is vitamin B9.  Folic acid is synthetically produced, and used in fortified foods and supplements on the theory that it is converted into folate, which may not be the case.

It appears that in both schizophrenia and autism there is a family of possible folate dysfunctions that range from minor to severe.  The mild dysfunction responds to a small supplement of folate, while the severe dysfunction requires a much larger supplement of folate.

Roger, another reader of this blog has the more severe dysfunction called Cerebral Folate Deficiency (CFD) and this condition is best studied by Vincent Ramaekers  (Department of Pediatric Neurology and Center of Autism, University Hospital Liege) and Richard Frye at the Arkansas Children’s Hospital.

Cerebral folate deficiency as diagnosed by Ramaekers/Frye is extremely rare.

In a previous post we looked at Biotin (vitamin B7) and we saw that while biotin/biotinidase deficiency is technically extremely rare, a partial deficiency seems to exist in about 5% of people with autism.  

Both severe biotin/biotinidase deficiency and partial biotin/biotinidase deficiency responds well to high dose biotin supplementation.

Without going into the details of Folate Receptor Autoantibodies (FRAs), it is clear that Ramaekers has found the same condition in both Schizophrenia and Autism.

The milder folate dysfunction is very well known in schizophrenia.

The Chinese Trial

On the basis that bigger is better, a clinical trial is underway in China on 330 subjects with Schizophrenia to measure the benefit of Mirtazapine and/or folate as an add-on therapy.

Evaluation of Mirtazapine and Folic Acid for Schizophrenia:(RECOVERY2)

I was quite surprised to come across this trial.

Today’s Post

Today’s post will look at the known effects of Mirtazapine and folate in schizophrenia and also the role folate plays in human biology.

There are lab tests that you could make to check for Folate dysfunction, just as there are for Biotin dysfunction. 

The standard therapy for Cerebral Folate Deficiency is the prescription drug leucovorin, normally used in cancer therapy.  There is also a supplement called Metafolin (Levomefolate calcium) that should have a very similar, if not identical, effect. Metafolin is produced by Merck and sold to supplement companies on the basis that it is only sold in low doses.  Metafolin appears more than your average “supplement”.

Another producer of Levomefolate calcium, is Pamlab; they sell it as a treatment for memory loss and peripheral neuropathy.  Pamlab was purchased by Nestlé Health Science in 2013; the Swiss tend to know what they are doing.

Schizophrenia

Schizophrenia overlaps significantly with autism in terms of its genetic origin.

Interestingly, people with schizophrenia may have a high rate of irritable bowel syndrome, but they often do not mention it unless specifically asked.

To better understand the clinical trials you need to know that the schizophrenia is a spectrum like autism with three main problem areas:-

Positive symptoms

These are symptoms that most individuals do not normally experience but are present in people with schizophrenia. They can include delusions, disordered thoughts and speech, and tactile, auditory, visual, olfactory and gustatory hallucinations, typically regarded as manifestations of psychosis. Hallucinations are also typically related to the content of the delusional theme. Positive symptoms generally respond well to medication.

Negative symptoms

These are deficits of normal emotional responses or of other thought processes, and are less responsive to medication. They commonly include flat expressions or little emotion, poverty of speech, inability to experience pleasure,lack of desire to form relationships, and lack of motivation. Negative symptoms appear to contribute more to poor quality of life, functional ability, and the burden on others than do positive symptoms. People with greater negative symptoms often have a history of poor adjustment before the onset of illness, and response to medication is often limited.

 

Cognitive dysfunction

The extent of the cognitive deficits an individual experiences is a predictor of how functional an individual will be, the quality of occupational performance, and how successful the individual will be in maintaining treatment.  The presence and degree of cognitive dysfunction in individuals with schizophrenia has been reported to be a better indicator of functionality than the presentation of positive or negative symptoms

Effective psychiatric drugs only exist for the positive symptoms, they do not exist for the negative symptoms or the cognitive dysfunction.

Folate Deficiency in Schizophrenia

Folate treatment in schizophrenia is linked to improvement in the negative symptoms that are normally untreatable.

Studies are mixed, but subgroups clearly exist in schizophrenia where folate supplementation improved well-being.

The rare severe dysfunction which is Cerebral Folate Deficiency is shown to exist in schizophrenia. 

Folate and vitamin B12 supplementation reduces disabling schizophrenia symptoms in patients with specific gene variants

Participants were all taking antipsychotic medications – which have been shown to alleviate positive symptoms, such as hallucinations and delusions, but not negative symptoms – and were randomized to receive daily doses of either folate and vitamin B12 or a placebo for 16 weeks. Every two weeks their medical and psychiatric status was evaluated, using standard symptom assessment tools along with measurements of blood levels of folate and homocysteine, an amino acid that tends to rise when folate levels drop. Nutritional information was compiled to account for differences in dietary intake of the nutrients. Participants' blood samples were analyzed to determine the variants they carried of MTHFR and three other folate-pathway genes previously associated with the severity of negative symptoms of schizophrenia. 

Among all 140 participants in the study protocol, those receiving folate and vitamin B12 showed improvement in negative symptoms, but the degree of improvement was not statistically significant compared with the placebo group. But when the analysis accounted for the variants in the genes of interest, intake of the two nutrients did provide significant improvement in negative symptoms, chiefly reflecting the effects of specific variants in MTHFR and in a gene called FOLH1. Variants in the other two genes studied did not appear to have an effect on treatment outcome.

  

Folate and vitamin B12 status in schizophrenic patients

CONCLUSIONS:

This study showed that folate deficiency is common in schizophrenic patients; therefore, it is important to pay attention to folate levels in these patients.

Folinic acid treatment for schizophrenia associated with folate receptor autoantibodies

  

The Role of Folate/vitamin B9 in Human Biology

Vitamin B₉ is essential for numerous bodily functions. Humans cannot synthesize folates de novo; therefore, folic acid has to be supplied through the diet to meet their daily requirements. The human body needs folate to synthesize DNA, repair DNA, and methylate DNA as well as to act as a cofactor in certain biological reactions.

Folic acid is synthetically produced, and used in fortified foods and supplements on the theory that it is converted into folate.  To be used it must be converted to tetrahydrofolate (tetrahydrofolic acid) by dihydrofolate reductase (DHFR). Increasing evidence suggests that this process may be slow in humans.

Note betaine below, which is also used to treat Cerebral Folate Deficiency, along with NAC.

Source: https://commons.wikimedia.org/wiki/File:MTHFR_metabolism.svg

Folic Acid, Folinic Acid and Folate

The terminology is confusing; what we want is folate, but there are several ways to get it.  Folic acid does not appear to be a good way.  Folinic acid, Levomefolic acid and Levomefolate calcium look to be the most effective supplements.

Here is a brief summary from Wikipedia:_

Folinic acid  or leucovorin, generally administered as the calcium or sodium salt (calcium folinate, sodium folinate, leucovorin calcium, leucovorin sodium), is an adjuvant used in cancer chemotherapy involving the drug methotrexate. It is also used in synergistic combination with the chemotherapy agent 5-fluorouracil.

Folinic acid (also called 5-formyltetrahydrofolate) was first discovered in 1948 as citrovorum factor and occasionally is still called by that name. Folinic acid should be distinguished from folic acid (vitamin B₉). However, folinic acid is a vitamer for folic acid, and has the full vitamin activity of this vitamin.

Levomefolic acid is the primary biologically active form of folic acid used at the cellular level for DNA reproduction, the cysteine cycle and the regulation of homocysteine. It is also the form found in circulation and transported across membranes into tissues and across the blood-brain barrier. In the cell, L-methylfolate is used in the methylation of homocysteine to form methionine and tetrahydrofolate (THF). THF is the immediate acceptor of one carbon units for the synthesis of thymidine-DNA, purines (RNA and DNA) and methionine. The un-methylated form, folic acid (vitamin B₉), is a synthetic form of folate, and must undergo enzymatic reduction by methylenetetrahydrofolate reductase (MTHFR) to become biologically active.

It is synthesized in the absorptive cells of the small intestine from polyglutamylated dietary folate. It is a methylated derivative of tetrahydrofolate. Levomefolic acid is generated by MTHFR from 5,10-methylenetetrahydrofolate (MTHF) and used to recycle homocysteine back to methionine by 5-methyltetrahydrofolate-homocysteine methyltransferase(MTR) also known as methionine synthase (MS).
Levomefolic acid (and folic acid in turn) has been proposed for treatment of cardiovascular disease and advanced cancers such as breast and colorectal cancers. It bypasses several metabolic steps in the body and better binds thymidylate synthase with fDump, a metabolite of the drug fluorouracil.

Levomefolate calcium, a calcium salt of levomefolic acid, is sold under the brand names Metafolin (a registered trademark of Merck KGaA) and Deplin (trademark of Pamlab, LLC). Methyl folate can be bought at online stores or in some chemists though without a prescription.

A good choice seems to be Metafolin, like in this product:-

Folate and Autism

We know from Roger and Frye/Ramaekers that the rare condition condition Cerebral folate deficiency (CFD) exists in autism, but what about the more widespread milder dysfunction like that found in schizophrenia?

As usual the level of knowledge in autism is less than that in schizophrenia.  The paper below concludes that when it comes to autism, not much is known.

Folic acid and autism: What do we know?

 

Autism spectrum disorders (ASD) consist in a range of neurodevelopmental conditions that share common features with autism, such as impairments in communication and social interaction, repetitive behaviors, stereotypies, and a limited repertoire of interests and activities. Some studies have reported that folic acid supplementation could be associated with a higher incidence of autism, and therefore, we aimed to conduct a systematic review of studies involving relationships between this molecule and ASD. The MEDLINE database was searched for studies written in English which evaluated the relationship between autism and folate. The initial search yielded 60 potentially relevant articles, of which 11 met the inclusion criteria. The agreement between reviewers was κ = 0.808. The articles included in the present study addressed topics related to the prescription of vitamins, the association between folic acid intake/supplementation during pregnancy and the incidence of autism, food intake, and/or nutrient supplementation in children/adolescents with autism, the evaluation of serum nutrient levels, and nutritional interventions targeting ASD. Regarding our main issue, namely the effect of folic acid supplementation, especially in pregnancy, the few and contradictory studies present inconsistent conclusions. Epidemiological associations are not reproduced in most of the other types of studies. Although some studies have reported lower folate levels in patients with ASD, the effects of folate-enhancing interventions on the clinical symptoms have yet to be confirmed.

Given the anecdotal evidence, including from our reader Seth, and the close biological relationship between autism and schizophrenia it seems pretty clear that a sub-group of people with autism do have a folate dysfunction that should respond to supplementation.  

How big this subgroup is remains to be seen.  For biotin it is about 5%, for vitamin B12 it about 10%.  Given it is known that MTHFR mutations are very common in autism, for example 23% were found to have the homozygous mutation 677CT allele (see the study below), it is very likely to be a sizeable group.  MTHFR is only one of the genes that could cause a folate problem.

Association of MTHFR Gene Variants with Autism

A trial of metafolin could be a rewarding experience for some.

Back to the second half of that big Chinese Trial - Mirtazapine

There is a wealth of research that looks into the benefit of Mirtazapine in schizophrenia.  I choose to highlight a study from Finland because it is extremely comprehensive.

Effects of add-on mirtazapine on neurocognition in schizophrenia

It has been reported earlier, from another part of this study, that clear-cut differences in all PANSS subscales and a large effect size of 1,00 (CI95% 0,23-1,67) on the PANSS total scores resulted from mirtazapine treatment when compared with a placebo in both within group and between group analyses during the double-blind phase (Joffe et al. 2009). In the open label phase, patients who switched to mirtazapine treatment demonstrated a clinical improvement in the same manner as their mirtazapine-treated counterparts in the double-blind phase. Prolonged treatment with mirtazapine led to more prominent improvements in clinical parameters than short-term treatment. A trend towards improvement was seen in all measured parameters, therefore providing more evidence of mirtazapine’s beneficial effect on schizophrenia symptoms.

The actual mechanism for a potential neurocognitive enhancing effect of mirtazapine in schizophrenia remains unknown, but it may be elucidated from its receptor binding profile. Like most SGAs, mirtazapine could also increase prefrontal dopaminergic and noradrenergic activity via 5-HT2A or 5-HT2C receptor blockade, as demonstrated in animal models (Liegeois et al. 2002; Meneses 2007; Zhang et al. 2000), and thus improve neurocognitive performance. Secondly, 5-HT3 receptor modulation by mirtazapine could also improve neurocognition (Akhondzadeh et al. 2009), presumably through increased release of acetylcholine (Ramirez et al. 1996). Thirdly, mirtazapine might improve neurocognition as a result of the indirect agonism of 5-HT1A receptors (Sumiyoshi et al. 2007). Moreover, mirtazapine is a more potent alpha-2 receptor antagonist than clozapine, which may explain its additional neurocognition-enhancing effect, even if it is added to clozapine (as in the study reported by Delle Chiae et al. 2007). The alpha-2 receptors remain an important target for neurocognitive research and its down-regulation may enhance neurocognition through a noradrenaline-mediated modulation of response to environmental stimuli (Friedman et al. 2004). Furthermore, alpha-2 receptor antagonism seems to boost hippocampal neurogenesis (Rizk et al. 2006). Also, mirtazapine may actually boost levels of brain-derived neurotrophic factor (BDNF) Rogoz et al. 2005), which is a major mediator of neurogenesis 62 and neuroplasticity. Correspondingly, those who suffer from schizophrenia often have abnormally low BDNF serum levels (Rizos et al. 2008).

During the 6-week extension phase, patients who had previously received six weeks of mirtazapine and those on placebo both showed significant improvement on several neurocognitive tests. Twelve-week mirtazapine treatment demonstrated better neurocognitive outcome than just six weeks of mirtazapine treatment, as evaluated by Stroop Dots time and TMT-B, number of mistakes, which are associated with general improvement in mental speed/attention control and executive functions. Twelve-week mirtazapine add-on to antipsychotic treatment indicated additional neurocognitive improvements of just six weeks, which demonstrates a progressive therapeutic effect.

In earlier posts on Mirtazapine/Remeron I raised various possible modes of action and other readers added their further ideas.

The table below lists some of the possible modes of action.  I declare a bias towards the importance of histamine, but clearly many more things are involved.

A Review of the Pharmacological and Clinical Profile of Mirtazapine

Mirtazapine has been trialed for a vast range of conditions:

A Review of Therapeutic Uses of Mirtazapine in Psychiatric and Medical Conditions

Mirtazapine is an effective antidepressant with unique mechanisms of action. It is characterized by a relatively rapid onset of action, high response and remission rates, a favorable side-effect profile, and several unique therapeutic benefits over other antidepressants. Mirtazapine has also shown promise in treating some medical disorders, including neurologic conditions, and ameliorating some of the associated debilitating symptoms of weight loss, insomnia, and postoperative nausea and vomiting.

And even Fibromyalgia, which I did suggest was the “almost autism” for females:-

In a 6-week open-label trial of mirtazapine, 54% of the 26 fibromyalgia patients who completed the study demonstrated a clinically significant reduction in pain intensity and in mean weekly dosage of acetaminophen. Additionally, there was a significant improvement in sleep quality and somatic symptoms, including cold extremities, dry mouth, sweating, dizziness, and headache. Of note, the magnitude of reduction in major fibromyalgia symptoms was significantly correlated with the magnitude of reduction in depression

Mirtazapine in Autism

In the new trial of Mirtazapine in autism they have chosen to focus on anxiety.  That looks odd to me given the very wide scope of benefits seen in schizophrenia and the feedback of our reader who asked why Remeron was working wonders with his child.

As is often the case, this trial at Massachusetts General Hospital uses doses that are extremely high.  Given the numerous effects of this drug it is highly likely that the effect may be completely different at higher/lower doses.

Mirtazapine Treatment of Anxiety in Children and Adolescents With Pervasive Developmental Disorders

This study will determine the effectiveness of mirtazapine in reducing anxiety in children with autistic disorder, Asperger's disorder and Pervasive Developmental Disorder.

The starting dose for subjects is 7.5 mg daily. The maximum daily dose will be 45 mg.

I am very much in agreement with the readers of this blog using Mirtazapine at a lower dose.

As the schizophrenia trial showed, the effect grows over time, so better to try a low dose of 5mg for two months than race up to 45mg.