A novel PDE10A inhibitor just showed safety and efficacy in a large Phase 2 trial for acute schizophrenia. 👏
📌 PDE10A inhibitors represent a non-dopaminergic approach—targeting phosphodiesterase 10A to modulate both D1 and D2 pathways indirectly. This could be a game-changer for patients who don’t respond to or can’t tolerate traditional D2 blockers.
🔍 The trial demonstrated: ✅ Significant reduction in PANSS total scores ✅ Favorable side effect profile (no EPS or prolactin elevation) ✅ Oral formulation, once daily
This reinforces the urgent need to diversify our treatment mechanisms beyond dopamine antagonism. As treatment-resistant schizophrenia remains a major challenge, we’ll take all the innovation we can get.
🧠 Stay tuned—PDE10A could join the ranks of TAAR1 agonists and muscarinic agents in reshaping how we treat serious mental illness.
There is limited high-quality randomized controlled trial (RCT) evidence specifically comparing Zyprexa (olanzapine) or Seroquel (quetiapine) for the treatment of stimulant-induced psychosis (SIP), including cocaine-induced psychosis. However, some RCTs and observational studies provide useful insights:
Olanzapine (Zyprexa)
RCT Evidence:
A 2022 meta-analysis of antipsychotic treatments for stimulant-induced psychosis included olanzapine and found it to be effective in reducing positive psychotic symptoms, often comparable to haloperidol but with a better side effect profile (less extrapyramidal symptoms) 11.
A double-blind RCT comparing olanzapine vs. haloperidol in methamphetamine-induced psychosisfound that both were effective at reducing PANSS (Positive and Negative Syndrome Scale) scores, but olanzapine was associated with better tolerability 22.
Another RCT in methamphetamine-induced psychosis compared olanzapine and risperidone, showing similar efficacy but better tolerability with olanzapine 33.
Quetiapine (Seroquel)
RCT Evidence:
A small RCT in methamphetamine-induced psychosis found that quetiapine was effective but tended to require higher doses to achieve symptom resolution 44.
A retrospective study on cocaine-induced psychosis suggested that quetiapine may help reduce symptoms, but data is weaker compared to olanzapine or risperidone 55.
Quetiapine has also been studied as an option for reducing cocaine cravings, but results are mixed and it is generally less preferred for acute agitation compared to faster-acting options like olanzapine.
Head-to-Head Comparison
There is no direct RCT comparing olanzapine vs. quetiapine for stimulant-induced psychosis, but based on available data:
Olanzapine is generally preferred for acute agitation and psychosis because of its faster onset and greater D2 blockade.
Quetiapine may be useful in milder cases or for individuals needing sedation, but higher doses are often required.
Clinical Implications
For acute stimulant-induced psychosis, olanzapine (5–10 mg IM or PO) is a common first-line option due to rapid onset and favorable side effect profile.
Quetiapine (200–400 mg PO) can be considered, particularly for patients needing sedation or those with comorbid conditions like bipolar disorder.
Other antipsychotics with strong evidence include risperidone and haloperidol (though the latter has more extrapyramidal risk).
After reviewing the available literature, direct randomized controlled trials (RCTs) comparing olanzapine (Zyprexa) and quetiapine (Seroquel) for stimulant-induced psychosis (SIP), including cocaine-induced psychosis, remain scarce. However, some studies provide relevant insights:
Olanzapine (Zyprexa):
Efficacy: A randomized, double-blind trial compared olanzapine and haloperidol in patients with amphetamine-induced psychosis. Both medications effectively improved psychotic symptoms in the short term, with olanzapine showing a faster onset of action.
Quetiapine (Seroquel):
Efficacy: A double-blind RCT compared haloperidol and quetiapine for methamphetamine-induced psychosis. While both medications reduced psychotic symptoms, quetiapine appeared to have a more favorable profile in reducing certain symptoms over time.
Indirect Comparisons:
First-Episode Psychosis: A 52-week randomized, double-blind study evaluated olanzapine, quetiapine, and risperidone in early psychosis patients. All three antipsychotics demonstrated comparable effectiveness, as indicated by similar rates of treatment discontinuation.
Conclusion:
While direct RCT evidence comparing olanzapine and quetiapine specifically for stimulant-induced psychosis is limited, existing studies suggest that both medications are effective in managing such conditions. Olanzapine may offer a faster onset of symptom relief, whereas quetiapine might present a more favorable side effect profile. Clinical decisions should be individualized, considering factors such as patient history, specific symptomatology, and potential side effects.
Antipsychotic Drugs and Cognitive Function: Key Findings from a Systematic Review and Meta-Analysis
Background: Cognitive impairment is a core feature of schizophrenia, often leading to significant functional disability. Antipsychotic medications are the main treatment for schizophrenia, but their impact on cognitive function remains debated.
Objective: This systematic review and network meta-analysis aimed to compare the effects of different antipsychotic drugs on cognitive function in patients with schizophrenia.
Methods: The review included randomized controlled trials (RCTs) that assessed cognitive outcomes in patients with schizophrenia treated with antipsychotics. A network meta-analysis was conducted to compare the cognitive effects across different antipsychotic drugs.
Key Findings:
Cognitive Improvement:
All antipsychotics studied showed modest cognitive benefits, though the effect sizes were small.
Second-generation antipsychotics (SGAs) generally performed better than first-generation antipsychotics (FGAs).
Among SGAs, lurasidone and amisulpride demonstrated the most pronounced cognitive improvements.
FGAs like haloperidol showed the least benefit for cognitive function.
Domains of Cognitive Improvement:
The drugs improved different cognitive domains, including working memory, processing speed, and executive functioning, though no single drug showed superiority across all domains.
Comparative Effectiveness:
In head-to-head comparisons, lurasidone and amisulpride were consistently ranked higher for cognitive improvement.
Olanzapine and risperidone also showed beneficial effects, though to a lesser extent.
Adverse Effects and Tolerability:
Cognitive improvements were often seen alongside side effects, with some drugs (e.g., olanzapine) associated with metabolic risks that may counterbalance cognitive benefits.
Limitations:
The analysis emphasized the small effect sizes, suggesting that while antipsychotics may slightly improve cognition, the changes may not be clinically meaningful in many cases.
Cognitive rehabilitation therapies may need to be paired with pharmacological treatment for more significant cognitive gains.
Conclusions: While antipsychotics can modestly improve cognitive function in schizophrenia, the benefits are relatively small, and no drug significantly outperforms others across all cognitive domains. Lurasidone and amisulpride may offer the greatest cognitive benefits, but additional interventions may be necessary to address cognitive deficits effectively.
The TEMPO-3 trial focused on the use of rasagiline in patients with early Parkinson’s disease (PD). Rasagiline is a monoamine oxidase-B (MAO-B) inhibitor, which helps to increase dopamine levels by preventing its breakdown, potentially slowing the progression of Parkinson’s disease. Here are the key findings from the TEMPO-3 trial:
Slowed Progression of Symptoms: The trial found that early treatment with rasagiline at a dose of 1 mg/day slowed the progression of motor symptoms compared to delayed treatment, suggesting potential disease-modifying effects.
Improvement in Quality of Life: Patients who received rasagiline earlier in their treatment course experienced an improvement in daily activities and quality of life. This was measured by tools such as the Unified Parkinson’s Disease Rating Scale (UPDRS).
Well-Tolerated: Rasagiline was well-tolerated with a favorable safety profile. The side effects were mild and included headache, joint pain, and flu-like symptoms, but there were no significant safety concerns over the course of the trial.
Delay in Disability: The study hinted at rasagiline’s ability to delay the onset of disability by slowing motor symptom progression, which may result in a reduced need for other symptomatic treatments earlier in the disease course.
Overall, the TEMPO-3 trial supported rasagiline’s role as a first-line therapy in early Parkinson’s, emphasizing its benefit in delaying motor progression and potentially altering the disease course.
It wasn’t that long ago when I was sitting in lectures as a first-year psychiatry resident. I learned about the first- and second-generation antipsychotic medications in detail. One commandment that was always preached in my training was to never combine two antipsychotic medications because there is no additional benefit. Today we are here to explore this idea and see if there is truly no additional benefit to using two antipsychotics and explore why there is so much antipsychotic polypharmacy in serious mental illness.
Since most guidelines discourage the use of multiple antipsychotic medications, why are many psychiatrists going against these guidelines? In most cases we are just trying to stabilize patients, get them better, and keep them out of the hospital as the goal is to provide most psychiatric care in the community. To reach these goals a single medication does not always produce the desired results.
Patients that end up on multiple antipsychotics have some unique characteristics. They tend to have more severe psychotic symptoms, are male, unemployed, and younger. Those with frequent inpatient admissions on involuntary status are also more likely to end up on two medications.
What To Do When a Single Medication Is Not Enough?
The use of multiple antipsychotics is an area of limitted research. However, there is a difference between rational polypharmacy and irrational polypharmacy.
We should start this discussion by saying a patient should be started on monotherapy titrated to an effective dose and continued on the medication for 6 weeks prior to making a change. If the first medications fails, then switching to another medication or long acting injectable is a reasonable next step. If after another 6 weeks of treatment the patient remains unstable and symptomatic the technical next step is to start clozapine. There are many reasons why clozapine may not be a good option for a particular patient including the strict requirements for weekly complete blood cell counts CBCs.
Assuming this process is followed and the patient is still symptomatic what’s the next step?
Consider Receptor Binding Profiles
This is the first step in prescribing two medications rationally. Most first-generation medications such as Haldol will bind tightly to D2 receptors and stay bound to the sites longer. Second-generation medications like quetiapine are known to bind to the receptors and quickly dissociate giving an on-off like effect. Tight binding and longer duration of binding can lead to extrapyramidal side effects (EPS), whereas quick on-off medications like quetiapine have limitted EPS risk.
You should also consider other receptors the medication may target such as histamine and muscarinic cholinergic receptors. It would be best to avoid combining two medications that have high antihistamine and anticholinergic activity.
Let’s look at some scenarios where antipsychotic polypharmacy makes sense.
Patients With Acute Agitation
This is a common problem on the inpatient unit. A patient is on a low-potency quick on-off medication like quetiapine but remains symptomatic and is engaging in dangerous behavior.
The addition of a higher potency, higher affinity medication like Haldol makes some sense here. This will control the acute agitation, can be titrated until the psychotic aggression is controlled, and can be stopped as soon as the patient is stable on quetiapine. We can see how the receptor binding profile makes this combination reasonable.
Clozapine Refractory Patients
What do you do when a patient is on the best antipsychotic medication but remains symptomatic?
We do have several lines of evidence that we can look at for this question. One option is to add low dose risperidone. This is a similar idea to adding Haldol to quetiapine. Clozapine has lower affinity for the D2 receptor than risperidone which has much higher affinity for D2 receptors. There were two placebo-controlled trials that support this combination. Before combining medications, I would suggest obtaining a clozapine level to make sure it’s therapeutic.
There are two more recent studies that compared multiple antipsychotic medication combinations and used rehospitalization as a measure of effectiveness. Both studies found a significant reduction in rehospitalization for patients receiving polypharmacy compared to those receiving monotherapy. The best outcome was achieved when clozapine was combined with aripiprazole.
Patient is On a Long Acting Injectable (LAI) but Remains Symptomatic at the Highest Dose
This is a common problem because the doses of LAIs are limitted. For example, the LAI aripiprazole (Aristida) is limitted to a maximum dose of 20 mg/day. The oral formulations of aripiprazole allow for a maximum dose of 30 mg/day. One strategy is to give the injection early. This will usually be done on week 3 for formulations that last 4 weeks. Another option is to add another medication with a different receptor binding profile such as the clozapine aripiprazole combination that was shown to reduce the risk of rehospitalization.
Treatment of Insomnia
The addition of low dose quetiapine to a medication like paliperidone is common in clinical practice. Once D2 receptor blockade has been maximized by reaching an effective dose of paliperidone, considering the addition of as need (PRN) quetiapine for its low potency and sedating properties is reasonable. The medication should be used PRN only and should be removed once the insomnia has resolved. Consider a sleep study if sleep apnea is possible and using other options such as short-term orexin antagonists, melatonin, and sedating antidepressant if appropriate.
Treatment of Antipsychotic Induced Side Effects
I know what you are going to say, adding a medication to treat a side effect of another medication doesn’t make sense. Let’s take an example to illustrate why this makes sense. If a patient is stable on risperidone and is discovered to have an elevated prolactin level you have an obligation to address it. The addition of low dose aripiprazole has been proven to reduce prolactin levels in these cases. Another possibility is using aripiprazole to reduce the metabolic burden of medications such as clozapine. There is much more limited data in this area and I would consider metformin a much better option to start with if antipsychotic induced weight gain is a problem.
In the process of Switching Medication the Patient Achieves Remission
This is another common clinical scenario. A patient didn’t respond to a medication, and you begin decreasing the dose of the first medication while titrating the new medicine. Then suddenly they are better. You don’t know why but they are better than they have ever been and now you are afraid to make any additional changes. Ideally you would finish the process and appropriately titrate the new medicine while discontinuing the ineffective medication. There is no good data to support inadequate dosing of two antipsychotics, and it’s best to continue your taper/titration and reevaluate after it’s complete.
Conclusion
There is still limited data to support the use of multiple antipsychotic medications although it is often seen in clinical practice. There are a few places where the addition of a second medication makes sense, and we can use receptor profiles to help us make rational decisions and avoid excess side effect burden.
There has been a lot of news recently about Sam Bankman, the onetime billionaire turned supervillain. At its peak, his company FTX had an in-house performance coach and psychiatrist named George K. Lerner. It’s unclear how many FTX employees Dr. Lerner treated but he did admit to treating some for ADHD and stated “the rate of ADHD at FTX was in line with most tech companies” whatever that means. I’m not here to debate the practices of the good doctor, but Bankman was known to talk publicly about experimenting with focus-enhancing medications. The main medications he allegedly used to become limitless were stimulants such as Adderall and the more interesting one to me and the topic of this week’s video the selegiline patch.
We are going to discuss selegiline in depth and try to understand why a medication primarily used to treat Parkinson’s may be useful for enhancing focus, creativity, and productivity in the fast-paced world of cryptocurrency.
What is Selegiline?
Although many may not have heard of this medication, it’s actually a very old concept in psychiatry. A common “pimping” question in psychiatry residency is what was the first antidepressant medication? Most residents will say it was the tricyclic antidepressants which isn’t a bad guess but it’s not correct. The correct answer is the monoamine oxidase inhibitors (MAOIs) specifically iproniazid a failed treatment for tuberculosis. In 1952 researcher noted that patients receiving this medication became unusually happy, this was shocking considering the medication did nothing for their tuberculosis.
Transdermal selegiline is a tissue selective MAOI (MAO-A and MAO-B inhibitor in the brain) and a relatively selective MAO-B inhibitor in the gut. This is an important point, and I will explain more about it as we move through this topic.
How Do MAOIs Work?
We are speaking about the transdermal selegiline patch here but there is also an oral version that is not approved for major depressive disorder and is a selective MAO-B inhibitor.
The transdermal patch acts in the brain as an irreversible inhibitor of both MAO-A and MAO-B which are enzymes responsible for breaking down norepinephrine, serotonin, and dopamine which in turn will boost the noradrenergic, serotonergic, and dopaminergic neurotransmission.
In lay terms this medication increases the availability of all three major neurotransmitters so that more serotonin, norepinephrine, and dopamine is available to act on post synaptic receptors affecting changes in cells and circuits involved in depression.
FDA Approvals for Selegiline
This is a little complicated because news outlets have stated the medication is only used for Parkinson’s disease which is true if we are talking about the oral tablets. The transdermal patch is FDA approved for major depressive disorder.
Off label use includes the treatment of treatment resistant depression, panic disorder, social anxiety (which MAOIs are usually superior at treating), treatment resistant anxiety, and Alzheimer’s disease.
How to Dose Selegiline
The transdermal patch comes in various doses:
6 mg/24 hours
9 mg/24 hours
12 mg/24 hours
The initial dose for depression is 6 mg/24 hours and it can be increased by 3 mg/24 hours every 2 weeks to a maximum dose of 12 mg/24 hours. Dietary modification to restrict tyramine from food sources is not required for the 6 mg/24hr patch but at higher doses the same food restrictions are required as other oral MAOIs such as phenelzine. This will be important for our next discussion on side effects.
Side Effects of Selegiline
Before starting the medication, the patient should be aware of the potential for increased blood pressure.
Notable Side effects include
Skin reactions at the site of application (the location of the patch should be rotated daily)
Headaches
Dry mouth
Diarrhea
Insomnia
Sedation
Possible weight gain
Serious side effects include:
Hypertensive Crisis
Seizure
Induction of manic episodes in bipolar disorder
Contraindications when combined with:
Meperidine
Another MAOI
SSRIs, SNRIs, TCAs, tramadol
Dextromethorphan
St. John’s wort
Methadone
History of Pheochromocytoma
Elective surgery
Proven allergy to selegiline
The Dreaded Tyramine Reaction
I believe that MAOIs might be the most effective of the antidepressants because of their ability to affect all three major neurotransmitter circuits, but they are rarely used clinically. In most residency training programs, we are not taught to use these medications. The main barrier is the dietary restrictions and risk for hypertensive crisis if the diet is not followed.
This diet should be started a week or so before staring the medication. It allows the patient time to get accustomed to the dietary recommendations before being on the medication when the stakes are higher. The diet must be followed for 2 weeks after stopping the MAOI as it can take time for the MAO enzymes to regenerate due to irreversible inhibition.
Tyramine is an amino acid that is found in some foods, and it helps to regulate blood pressure. MAOIs are responsible for breaking this amino acid down so it’s inactive and unable to causes an increase in blood pressure. When you block MAO excess tyramine will be available to affect blood pressure.
Ingestion of a high tyramine meal is generally considered to be any meal with 40 mg or more in the fasted state. For the low dose transdermal patch 6 mg/24 hours studies show that 200-400 mg of tyramine in the fasted state is required for a hypertensive response. In general, at low doses dietary modification is not required. If the dose is increased to 12 mg/24 hours than 70-100 mg of tyramine is required for a hypertensive response. Although dietary modification may not be required at higher doses, it’s safer to avoid tyramine rich foods once the selegiline dose is increased and to be cautious at lower doses as well.
Low Tyramine Diet Principles
When a patient is on an MAOI diet they should only eat things that are fresh. This goes for food that are stored as well as the storage process may affect the tyramine content. The patient should avoid foods that are beyond their expiration date and avoid fruits and vegetables that are overly ripe. Some cheeses are allowed in the diet, but all aged cheese should be avoided. The same can be said for meat products, fresh meats are fine, but aged or spoiled meats should be avoided.
Fermented products need to be avoided when MAOIs are being used. This goes for all fermented products without exception.
Chinese food and some other eastern foods should be avoided because they contain soy, shrimp paste, tofu, and soy sauces all of which are high in tyramine.
Fava and other broad beans should be avoided this includes Italian green beans.
Foods to Avoid
Matured or aged cheeses (cheddar, and blue examples)
Cheeses: cream cheese, ricotta, fresh cottage cheese, mozzarella, processed cheese slices like American cheese
Milk Products: yogurt, sour cream, and ice cream
Meat: fresh packaged or processed meat e.g. hot dogs
Beverages: coffee, tea, soda, up to a maximum of 2 drinks either 12 oz of canned or bottled beer or 4 oz of red/white wine.
Soy products: soy milk
Other foods: chocolate in moderation and monosodium glutamate in moderation
Onset of Action
The therapeutic effect is usually not immediate and still requires 2-4 weeks or longer once an adequate dose is reached.
Augmentation
For expert psychopharmacologist Only:
You may consider a stimulant such as d-amphetamine, or methylphenidate while watching for increased blood pressure, suicidal ideation, and activation of bipolar disorder)
Lithium
Seconded generation dopamine blocking medication
Mood stabilizing anticonvulsant
Advantages to using MAOIs
May be effective in treatment resistant depression
May improve atypical depressive symptoms such as hypersomnia and hyperphagia
Lower risk for weight gain and sexual side effects
Why Would Selegiline Improve Cognitive function?
Selegiline will increase dopamine and more dopamine in the prefrontal cortex theoretically will enhance cognitive function. A lot of the research on MAOIs and cognitive enhancement come from studies in neurodegenerative disorders such as Alzheimer’s disease. While promising as reported in several articles it does not appear that proper randomized controlled trials were ever conducted. If you watch my videos than you should know the risk of assuming that something that should theoretically work will also work clinically. This is the story of many medications in psychiatry. We also cannot extrapolate that to healthy individuals who do not have neurodegenerative disorders.
Selegiline is metabolized to l-amphetamine, and l-methamphetamine which are well known stimulants that may improve symptoms of attention deficit hyperactivity disorder (ADHD). Again, this is theoretical and has never been proven but based on the metabolism of the medication it makes sense that it may enhance cognition in those with ADHD or even healthy individuals.
People often forget that depression itself is a major reason for cognitive problems. Depression in elderly patients is sometimes referred to as pseudodementia because it can look like the individuals has substantial cognitive deficits in severe cases. It’s possible that the improvement in depressive symptoms is responsible for the enhanced cognitive function.
Conclusion
I think this is a good discussion because it highlights an often-forgotten class of medication in modern psychiatry that can be utilized for patients who have failed other medication options. Many psychiatrists are untrained or too scared to use these medications clinically. As far as cognitive enhancement and finding that limitless pill, I do not think this is it. While it may theoretically improve cognitive function it’s never been proven in randomized controlled trials. I would say the evidence supporting this idea is weak and may even be dangerous given the risk for hypertensive crisis.
Quetiapine offers some benefits over other dopamine blocking medications. It has a much lower risk for EPS and a broad spectrum of effects. The main limitations are weight gain, sedation, and orthostasis. The extended-release formulation offers a once nightly dosing that can reduce daytime sedation.
It has a number of FDA approved indications including use in schizophrenia, bipolar disorder, bipolar depression, and major depression as an adjunct
It’s mechanism of action is blocking dopamine D2 receptors which targets positive symptoms of psychosis and serotonin 2A receptors which enhance dopamine release in certain regions of the brain reducing motor side effects and possibly improving cognitive side effects. It’s effects on depression and bipolar depression may be related to 5HT1A partial agonist activity, norepinephrine reuptake blockade, and 5HT2C and 5HT7 antagonist properties.
Clinically quetiapine is often underdosed and stopped or switched before an adequate trial is completed. Higher doses generally achieve greater response for manic or psychotic symptoms.
For schizophrenia start with 25 mg BID or 300 mg XR QHS. Target doses 400-800 mg/day
For bipolar start with 50 mg BID or 300 XR QHS. With a target dose of 400-800 mg daily for mania and 300 mg/day for depression (studies indicate that 600 mg was not better for depression than 300 mg)
For depression start at 50-100 mg/day in divided doses with a target of 150-300 mg/day (data indicates that 150 mg and 300 mg do equally well so either dose is appropriate depending on patient response)
You can increase the dose 50-100 mg/day every 1-4 days to a target dose
The max daily dose in adults is 800 mg/day, occasionally patients may require 800-1,200 mg/day for psychosis or mania
Monitoring is similar to other dopamine blocking medications, specifically fasting blood glucose and lipid profile, BMI, blood pressure
Side effects include sedation, hypotension, dry mouth, dizziness, constipation, weight gain and fatigue. Watch for orthostatic hypotension at high doses or with rapid titration. There is essentially no motor side effects or prolactin elevation.
For XR formulations do not crush or chew them, if a patient has been off the medication for more than 1 week you want to restart as if initial therapy. Quetiapine has some abuse potential reported in the literature particularly in incarcerated populations
In the initial studies with beagle dogs cataracts developed but human studies have not shown this association
