PSSD Patients Needed for CCM Investigation

A brief recap

In October 2022, we ran a blog post aimed at recruiting patients in the UK with post-SSRI sexual dysfunction (PSSD) who could be tested for small fibre neuropathy. This was to be done by skin biopsy which is the standard method for investigating the condition.

The project was in response to information provided by a Finnish PSSD group in which several members had undergone skin biopsy and were found to be positive for small fibre neuropathy. RxISK had previously considered a possible link between PSSD and small fibre neuropathy, but difficulties in arranging skin biopsies meant that we didn’t pursue it any further. The information from the Finnish group renewed our interest and seemed worth exploring.

Unfortunately, we reported in March 2023 that our plans had run into problems. Many people had tried to push their way onto the project by contacting the neurologist directly and desperately pleading their case. This caused significant problems for the neurology department and seems to have been a major factor in the hospital being reluctant to proceed any further.

From skin biopsy to CCM

A few weeks ago, we ran a post about a new imaging technique being used to diagnose small fibre neuropathy – corneal confocal microscopy (CCM). It involves taking an image of the eye and looking for nerve problems.

Compared to skin biopsy, CCM has the advantage of being non-invasive and seems to be just as accurate at detecting peripheral neuropathies. The downside is that few clinics offer this type of testing, which at the moment makes it difficult to arrange – but this seems to be changing rapidly.

However, we have recently connected with two groups of researchers in Australia and the UK who use CCM, and who have been able to tell us more about it. We have also been able to compile a more extensive list of clinics who offer this service – see the recent post.

The next step is to find a clinic or two willing to test a group of 5 PSSD patients. There are lots of clinics who will take your money and do tests, but if they aren’t interested in PSSD they will not be looking at your nerve endings with the kind of attention needed to spot problems. It may need looking at a group of patients in order to get a sense of what might be going on in PSSD.

It’s almost pointless, therefore, at the moment for one person to go along to one clinic and get tested.

A further issue is that the gateway to getting tested runs through ophthalmologists who are not naturally going to think PSSD has anything to do with them. They are going to need an overture aimed at generating enough interest to make them willing to see a group of 5 subjects. It’s going to take a bunch of emails from RxISK, with our SSRI and vision paper attached, and then assessment of any responses to see what the best options are in terms of choosing a clinic.

In order to make the strongest case when approaching the clinics, we would like to have the participants already in place.

How to apply

At the moment the best options look like being in the UK, Australia or Germany.

So we need 5 people who meet criteria in each of those countries.

• Ideally not too old.
• Ideally on no other medications.
• Males or females can take part.
• If you’ve had laser eye treatment you may not be suitable.

In the UK, you are likely to need a referral from your family doctor (GP).

In Australia and Germany, the researchers should be able to accept referrals from Professor Healy, although you may need to provide us with a printout of your medical history summary from your GP. This is to make sure you have no other conditions and no recent blood tests showing other problems.

If you also have visual disturbances that seem linked to your antidepressant, this would be helpful to include in the referral note.

To be considered for the testing, you will need to meet the published diagnostic criteria for PSSD. More information about the criteria can be found at the link provided, but they are summarised below:

Necessary
(1) Prior treatment with a serotonin reuptake inhibitor.
(2) An enduring change in somatic (tactile) or erogenous (sexual) genital sensation after treatment stops.

Additional
(3) Enduring reduction or loss of sexual desire.
(4) Enduring erectile dysfunction (males).
(5) Enduring inability to orgasm or decreased sensation of pleasure during orgasm.
(6) The problem is present for ≥3 months after stopping treatment.

There should be
(7) No evidence of pre-drug sexual dysfunction that matches the current profile.
(8) No current medical conditions that could account for the symptoms.
(9) No current medication or substance misuse that could account for the symptoms.

As an extra

(10) If you have vision problems that began after starting an antidepressant and have persisted after stopping this would be good to know about.

We need to make sure that everyone involved is suitable and doesn’t have anything in their medical history or clinical presentation that could undermine the testing.

Unfortunately after the Sheffield experience, the plan is to give the names of those chosen to whichever centre or centres have agreed to participate and suggest that they only accept these people for initial testing.

If it turns out there is a distinctive change linked to PSSD, everybody can go along to the clinic nearest them and we will be able to provide you with details about what has been found and exactly what to tell your ophthalmologist and optometrist to look for. At the moment, we don’t know that and going along and getting a negative result, when there is something there to be found, would be a disaster.

If you would like to register, the first step is to complete and return this form with details of your case. All of the cases will be reviewed for suitability, and you will then be contacted for any further information such as your medical history summary. We will let you know if a GP referral is also required.

Can you help?

CCM is not a treatment. No-one who is not in the first group of 5 will be losing out because they are not in that group. We may find nothing useful – not because there are no nerve changes but for instance because the problem might only affect what are called CT fibres and these may not be present in the cornea.

Everyone who has PSSD, PFS or PRSD can help by spreading the word about this project to as many PSSD sufferers in the UK, Australia and Germany as possible.

If we get a positive result, we need to build up a list of clinics internationally where CCM is being used. There will usually be an ophthalmologist who controls access to CCM testing, and we ideally need a name and email address for this person. If we have a positive result, we will be able to provide a template letter to inform ophthalmologists and others what to look for.