PAK inhibitors and potentially treating some Autism using Grandpa’s Medicine Cabinet

I wrote several posts about why PAK1 inhibitors should be beneficial in some autism and indeed some schizophrenia.

We also saw that PAK1-blocking drugs could be potentially useful for the treatment of neurofibromatosis type 2, in addition to RAS-induced cancers and neurofibromatosis type 1.

One problem with drugs developed for cancer is that, even if they finally get approved, they tend to be ultra-expensive.  Production volumes are low because even if they “work” they do not prolong life for so long and cancer has numerous sub-types.

Cheap drugs are ones used to treat common chronic conditions like high blood pressure, high cholesterol and indeed treatment of male lower urinary tract symptoms (LUTS), like benign prostatic hyperplasia (BPH).

A small number of readers of this blog have confirmed the beneficial effect of PAK inhibitors in their specific sub-types of autism.  The problem is that there are no potent PAK1 inhibitors suitable for long term use that are readily available.

The anti-parasite drug Ivermectin is an extremely cheap PAK1 inhibitor, but cannot be used long term, due to its other effects.

Propolis containing CAPE (Caffeic Acid Phenethyl Ester) is a natural PAK1 inhibitor, but may not be sufficiently potent as is reported by people with neurofibromatosis.

You would think somebody would just synthesize CAPE (Caffeic Acid Phenethyl Ester) artificially and then higher doses could be achieved.

PAK Inhibitors and Treatment of Prostate Enlargement

I was rather surprised that research has recently been published suggesting that PAK inhibitors could be used to treat the prostate enlargement, common in most older men. 

P21-Activated Kinase Inhibitors FRAX486 and IPA3: Inhibition of Prostate Stromal Cell Growth and Effects on Smooth Muscle Contraction in the Human Prostate

Abstract

Prostate smooth muscle tone and hyperplastic growth are involved in the pathophysiology and treatment of male lower urinary tract symptoms (LUTS). Available drugs are characterized by limited efficacy. Patients’ adherence is particularly low to combination therapies of 5α-reductase inhibitors and α₁-adrenoceptor antagonists, which are supposed to target contraction and growth simultaneously. Consequently, molecular etiology of benign prostatic hyperplasia (BPH) and new compounds interfering with smooth muscle contraction or growth in the prostate are of high interest. Here, we studied effects of p21-activated kinase (PAK) inhibitors (FRAX486, IPA3) in hyperplastic human prostate tissues, and in stromal cells (WPMY-1). In hyperplastic prostate tissues, PAK1, -2, -4, and -6 may be constitutively expressed in catecholaminergic neurons, while PAK1 was detected in smooth muscle and WPMY-1 cells. Neurogenic contractions of prostate strips by electric field stimulation were significantly inhibited by high concentrations of FRAX486 (30 μM) or IPA3 (300 μM), while noradrenaline- and phenylephrine-induced contractions were not affected. FRAX486 (30 μM) inhibited endothelin-1- and -2-induced contractions. In WPMY-1 cells, FRAX486 or IPA3 (24 h) induced concentration-dependent (1–10 μM) degeneration of actin filaments. This was paralleled by attenuation of proliferation rate, being observed from 1 to 10 μM FRAX486 or IPA3. Cytotoxicity of FRAX486 and IPA3 in WPMY-1 cells was time- and concentration-dependent. Stimulation of WPMY-1 cells with endothelin-1 or dihydrotestosterone, but not noradrenaline induced PAK phosphorylation, indicating PAK activation by endothelin-1. Thus, PAK inhibitors may inhibit neurogenic and endothelin-induced smooth muscle contractions in the hyperplastic human prostate, and growth of stromal cells. Targeting prostate smooth muscle contraction and stromal growth at once by a single compound is principally possible, at least under experimental conditions.

It looks like a PAK inhibitor could potentially solve both the key problems in BPH and so replace the current therapies.

Existing Drugs for LUTS/BPH

Undoubtedly someone is going to wonder whether existing drugs for LUTS/BPH might improve autism.  This is actually possible, but totally unrelated to PAK1 inhibition and RASopathies.

Existing drugs are in two classes, 5α-reductase inhibitors and α₁-adrenoceptor antagonists.

α-adrenoceptor antagonists

Alpha blockers relax certain muscles and help small blood vessels remain open. They work by keeping the hormone norepinephrine (noradrenaline) from tightening the muscles in the walls of smaller arteries and veins, which causes the vessels to remain open and relaxed. This improves blood flow and lowers blood pressure.

Because alpha blockers also relax other muscles throughout the body, these medications can help improve urine flow in older men with prostate problems.

Selective α₁-adrenergic receptor antagonists are often used in BPH because it is the α₁-adrenergic receptor that is present in the prostate.

 α ₂-adrenergic receptors are present elsewhere in the body

Alpha-2 blockers are used to treat anxiety and post-traumatic stress disorder (PTSD). They decrease sympathetic outflow from the central nervous system. Post-traumatic stress disorder is an anxiety disorder that is theorized to be related to a hyperactive sympathetic nervous system.

Alpha-2 receptor agonists for the treatment of post-traumatic stress disorder

So a nonselective alpha blocker, like one given to an older man with high blood pressure and BPH, might well have an effect on some kinds of anxiety.

You would think that a selective alpha 2 blocker might be interesting, how about Idazoxan?

Idazoxan is a drug which is used in research. It acts as both a selective α2 adrenergic receptor antagonist, and an antagonist for the imidazoline receptor. Idazoxan has been under investigation as an antidepressant, but it did not reach the market as such. More recently, it is under investigation as an adjunctive treatment in schizophrenia. Due to its alpha-2 receptor antagonism it is capable of enhancing therapeutic effects of antipsychotics, possibly by enhancing dopamine neurotransmission in the prefrontal cortex of the brain, a brain area thought to be involved in the pathogenesis of schizophrenia.

Mirtazapine is a cheap generic drug used at high doses for depression.  It happens to be a selective alpha 2 blocker, but it has numerous other effects as well.  One reader of this blog does respond very well to Mirtazapine.

So realistically in Grandpa’s medicine cabinet there might a selective alpha 1 agonist or a non-selective alpha agonist, it is the latter type that might have an effect on some kinds of autism.

5α-reductase inhibitors

The pharmacology of 5α-reductase inhibition involves the binding of NADPH to the enzyme followed by the substrate. Specific substrates include testosterone, progesterone, androstenedione, epitestosterone, cortisol, aldosterone, and deoxycorticosterone.

Beyond being a catalyst in testosterone reduction, 5α-reductase isoforms I and II reduce progesterone to 5α-dihydroprogesterone (5α-DHP) and deoxycorticosterone to dihydrodeoxycorticosterone (DHDOC).

In vitro and animal models suggest subsequent 3α-reduction of DHT, 5α-DHP and DHDOC lead to neurosteroid metabolites with effect on cerebral function.

These neurosteroids, which include allopregnanolone, tetrahydrodeoxycorticosterone (THDOC), and 5α-androstanediol, act as potent positive allosteric modulators of GABA_A receptors, and have anticonvulsant, antidepressant, anxiolytic, prosexual, and anticonvulsant effects.

Inhibition of 5α-reductase results in decreased conversion of testosterone to DHT.

This, in turn, results in slight elevations in testosterone and estradiol levels. 

In BPH, DHT acts as a potent cellular androgen and promotes prostate growth; therefore, it inhibits and alleviates symptoms of BPH. In alopecia, male and female-pattern baldness is an effect of androgenic receptor activation, so reducing levels of DHT also reduces hair loss.

A new look at the 5alpha-reductase inhibitor finasteride

Finasteride is the first 5alpha-reductase inhibitor that received clinical approval for the treatment of human benign prostatic hyperplasia (BPH) and androgenetic alopecia (male pattern hair loss). These clinical applications are based on the ability of finasteride to inhibit the Type II isoform of the 5alpha-reductase enzyme, which is the predominant form in human prostate and hair follicles, and the concomitant reduction of testosterone to dihydrotestosterone (DHT). In addition to catalyzing the rate-limiting step in the reduction of testosterone, both isoforms of the 5alpha-reductase enzyme are responsible for the reduction of progesterone and deoxycorticosterone to dihydroprogesterone (DHP) and dihydrodeoxycorticosterone (DHDOC), respectively. Recent preclinical data indicate that the subsequent 3alpha-reduction of DHT, DHP and DHDOC produces steroid metabolites with rapid non-genomic effects on brain function and behavior, primarily via an enhancement of gamma-aminobutyric acid (GABA)ergic inhibitory neurotransmission. Consistent with their ability to enhance the action of GABA at GABA(A) receptors, these steroid derivatives (termed neuroactive steroids) possess anticonvulsant, antidepressant and anxiolytic effects in addition to altering aspects of sexual- and alcohol-related behaviors. Thus, finasteride, which inhibits both isoforms of 5alpha-reductase in rodents, has been used as a tool to manipulate neuroactive steroid levels and determine the impact on behavior. Results of some preclinical studies and clinical observations with finasteride are described in this review article. The data suggest that endogenous neuroactive steroid levels may be inversely related to symptoms of premenstrual and postpartum dysphoric disorder, catamenial epilepsy, depression, and alcohol withdrawal.

This would suggest that a 5α-reductase inhibitor, like finasteride, that might be among Grandpa’s tablets might very well have an effect on someone with GABAa dysfunction, this includes very many people with autism, schizophrenia and Down Syndrome.

Whether the effect will be good or bad is hard to say, and may well depend on whether other drugs that target GABA or NMDA receptors are being used. Due to their other effects, 5α-reductase inhibitors are usually only used in adults.

Merck developed a lower dose form of finasteride, called Prospecia to treat baldness, usually in men.  It is 20% the normal potency used for BPH.

Side effects

The current BPH drugs cause side effects in some people.  PAK1 inhibitors may also have some side effects.

Conclusion

Going back in the days of living with your extended family might make treating many people’s autism much simpler.  It looks like many older people’s drugs can be repurposed for some types of autism (ion channel modifying diuretics, calcium channel blockers, statins, even potentially intranasal insulin in some).  Because older people’s drugs are so widely used they are well understood and inexpensive.  

Clearly the research on PAK inhibitors for LUTS/BPH is at an early stage, but there is a huge potential market.   A widely available PAK1 inhibitor might be a big help to some people with autism, neurofibromatosis, other RASopathies, not just Grandpa’s prostate.

In addition to FRAX486 and IPA3, why doesn’t someone try synthetic CAPE, i.e. without the bees, as a PAK inhibitor?

Bioactivity and chemical synthesis of caffeic acid phenethyl ester and its derivatives.

There is far more chance of a PAK1 inhibitor coming to market for LUTS/BPH, or certain cancers than for autism.  That is a fact of life.

As for 5α-reductase inhibitors, like finasteride, we know from Hardan’s study on Pregnenolone at Stanford that this hormone can have a positive effect and we know that various natural steroid metabolites will modulate GABA subunits.  So it is quite likely that finasteride is going have a behavioral effect.  Perhaps Hardan would like to trial finasteride 5mg and 1mg (Prospecia) in some adults with autism. I suspect it will make some people “worse” and others somewhat “better”; so please do not report the “average” response, highlight the nature of the positive responders.

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.