An article published this week in the prestigious journal Nature Medicine documents what is believed to be the first evidence that Alzheimer’s disease can be transmitted from person to person.

The finding arose from long-term follow up of patients who received human growth hormone (hGH) that was taken from brain tissue of deceased donors.

Preparations of donated hGH were used in medicine to treat a variety of conditions from 1959 onwards – including in Australia from the mid 60s.

The practice stopped in 1985 when it was discovered around 200 patients worldwide who had received these donations went on to develop Creuztfeldt-Jakob disease (CJD), which causes a rapidly progressive dementia. This is an otherwise extremely rare condition, affecting roughly one person in a million.

What’s CJD got to do with Alzehimer’s?

CJD is caused by prions: infective particles that are neither bacterial or viral, but consist of abnormally folded proteins that can be transmitted from cell to cell.

Other prion diseases include kuru, a dementia seen in New Guinea tribespeople caused by eating human tissue, scrapie (a disease of sheep) and variant CJD or bovine spongiform encephalopathy, otherwise known as mad cow disease. This raised public health concerns over the eating of beef products in the United Kingdom in the 1980s.

Human growth hormone used to come from donated organs

Human growth hormone (hGH) is produced in the brain by the pituitary gland. Treatments were originally prepared from purified human pituitary tissue.

But because the amount of hGH contained in a single gland is extremely small, any single dose given to any one patient could contain material from around 16,000 donated glands.

An average course of hGH treatment lasts around four years, so the chances of receiving contaminated material – even for a very rare condition such as CJD – became quite high for such people.

hGH is now manufactured synthetically in a laboratory, rather than from human tissue. So this particular mode of CJD transmission is no longer a risk.

What are the latest findings about Alzheimer’s disease?

The Nature Medicine paper provides the first evidence that transmission of Alzheimer’s disease can occur via human-to-human transmission.

The authors examined the outcomes of people who received donated hGH until 1985. They found five such recipients had developed early-onset Alzheimer’s disease.

They considered other explanations for the findings but concluded donated hGH was the likely cause.

Given Alzheimer’s disease is a much more common illness than CJD, the authors presume those who received donated hGH before 1985 may be at higher risk of developing Alzheimer’s disease.

Alzheimer’s disease is caused by presence of two abnormally folded proteins: amyloid and tau. There is increasing evidence these proteins spread in the brain in a similar way to prion diseases. So the mode of transmission the authors propose is certainly plausible.

However, given the amyloid protein deposits in the brain at least 20 years before clinical Alzheimer’s disease develops, there is likely to be a considerable time lag before cases that might arise from the receipt of donated hGH become evident.

When was this process used in Australia?

In Australia, donated pituitary material was used from 1967 to 1985 to treat people with short stature and infertility.

More than 2,000 people received such treatment. Four developed CJD, the last case identified in 1991. All four cases were likely linked to a single contaminated batch.

The risks of any other cases of CJD developing now in pituitary material recipients, so long after the occurrence of the last identified case in Australia, are considered to be incredibly small.

Early-onset Alzheimer’s disease (defined as occurring before the age of 65) is uncommon, accounting for around 5% of all cases. Below the age of 50 it’s rare and likely to have a genetic contribution.

The risk is very low – and you can’t ‘catch’ it like a virus

The Nature Medicine paper identified five cases which were diagnosed in people aged 38 to 55. This is more than could be expected by chance, but still very low in comparison to the total number of patients treated worldwide.

Although the long “incubation period” of Alzheimer’s disease may mean more similar cases may be identified in the future, the absolute risk remains very low. The main scientific interest of the article lies in the fact it’s first to demonstrate that Alzheimer’s disease can be transmitted from person to person in a similar way to prion diseases, rather than in any public health risk.

The authors were keen to emphasise, as I will, that Alzheimer’s cannot be contracted via contact with or providing care to people with Alzheimer’s disease.

Steve Macfarlane, Head of Clinical Services, Dementia Support Australia, & Associate Professor of Psychiatry, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Attention deficit hyperactivity disorder (ADHD) is a condition that can affect all stages of life. Medication is not the only treatment, but it is often the treatment that can make the most obvious difference to a person who has difficulties focusing attention, sitting still or not acting on impulse.

But what happens once you’ve found the medication that works for you or your child? Do you just keep taking it forever? Here’s what to consider.

What are ADHD medications?

The mainstay of medication for ADHD is stimulants. These include methylphenidate (with brand names Ritalin, Concerta) and dexamfetamine. There is also lisdexamfetamine (branded Vyvanse), a “prodrug” of dexamfetamine (it has a protein molecule attached, which is removed in the body to release dexamfetamine).

There are also non-stimulants, in particular atomoxetine and guanfacine, which are used less often but can also be highly effective. Non-stimulants can be prescribed by GPs but this may not always be covered by the Pharmaceutical Benefits Scheme and could cost more.

How stimulants work

Some stimulants prescribed for ADHD are “short acting”. This means the effect comes on after around 20 minutes and lasts around four hours.

Longer-acting stimulants give a longer-lasting effect, usually by releasing medication more slowly. The choice between the two will be guided by whether the person wants to take medication once a day or prefers to target the medication effect to specific times or tasks.

For the stimulants (with the possible exception of lisdexamfetamine) there is very little carry-over effect to the next day. This means the symptoms of ADHD may be very obvious until the first dose of the morning takes effect.

One of the main aims of treatment is the person with ADHD should live their best life and achieve their goals. In young children it is the parents who have to consider the risks and benefits on behalf of the child. As children mature, their role in decision making increases.

What about side effects?

The most consistent side effects of the stimulants are they suppress appetite, resulting in weight loss. In children this is associated with temporary slowing of the growth rate and perhaps a slight delay in pubertal development. They can also increase the heart rate and may cause a rise in blood pressure. Stimulants often cause insomnia.

These changes are largely reversible on stopping medication. However, there is concern the small rises in blood pressure could accelerate the rate of heart disease, so people who take medication over a number of years might have heart attacks or strokes slightly sooner than would have happened otherwise.

This does not mean older adults should not have their ADHD treated. Rather, they should be aware of the potential risks so they can make an informed decision. They should also make sure high blood pressure and attacks of chest pain are taken seriously.

Stimulants can be associated with stomach ache or headache. These effects may lessen over time or with a reduction in dose. While there have been reports about stimulants being misused by students, research on the risks of long-term prescription stimulant dependence is lacking.

Will medication be needed long term?

Although ADHD can affect a person’s functioning at all stages of their life, most people stop medication within the first two years.

People may stop taking it because they don’t like the way it makes them feel, or don’t like taking medication at all. Their short period on medication may have helped them develop a better understanding of themselves and how best to manage their ADHD.

In teenagers the medication may lose its effectiveness as they outgrow their dose and so they stop taking it. But this should be differentiated from tolerance, when the dose becomes less effective and there are only temporary improvements with dose increases.

Tolerance may be managed by taking short breaks from medication, switching from one stimulant to another or using a non-stimulant.

Too many prescriptions?

ADHD is becoming increasingly recognised, with more people – 2–5% of adults and 5–10% of children – being diagnosed. In Australia stimulants are highly regulated and mainly prescribed by specialists (paediatricians or psychiatrists), though this differs from state to state. As case loads grow for this lifelong diagnosis, there just aren’t enough specialists to fit everyone in.

In November, a Senate inquiry report into ADHD assessment and support services highlighted the desperation experienced by people seeking treatment.

There have already been changes to the legislation in New South Wales that may lead to more GPs being able to treat ADHD. Further training could help GPs feel more confident to manage ADHD. This could be in a shared-care arrangement or independent management of ADHD by GPs like a model being piloted at Nepean Blue Mountains Local Health District, with GPs training within an ADHD clinic (where I am a specialist clinician).

Not every person with ADHD will need or want to take medication. However, it should be more easily available for those who could find it helpful.

Alison Poulton, Senior Lecturer, Brain Mind Centre Nepean, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.