Intrusive urges to jump: are they suicidal thoughts?
An intrusive urge to jump horrifies you and you want it gone. Suicidal thinking involves wanting, however ambivalently, to die. They are different, often confused, and the distinction matters.

Professionals get this one wrong in both directions, and both directions do harm. If you are having thoughts of jumping, turning the wheel, stepping into traffic, and you cannot tell what they mean, I want to help you tell.
Two different experiences
An intrusive urge of the kind that belongs to OCD arrives uninvited, horrifies you, and you want it gone. You are on the platform, the image of jumping comes, and everything in you recoils. You step back. You grip something. You start avoiding platforms. The thought is the last thing you want, and the distress you feel is the measure of how far it is from what you want.
Suicidal thinking runs in the other direction. It involves wanting, however ambivalently, however mixed with fear, to die, or to not be here, or for it to stop. The thought of the platform does not horrify; it may bring a kind of relief, or a sense of an option. The person is not recoiling from it. They are, at some level, drawn towards it.
The content can look identical: an image of jumping. The relationship to the image is opposite. One is a thought you are fighting off. The other is a thought you are, at least in part, considering.
Why they get confused
They get confused because the content is the same, and because a person describing "thoughts of jumping" to a GP or a crisis line will often be assessed as suicidal, whatever their relationship to the thought. That is understandable; the safe assumption from outside is the serious one. But it can leave someone with OCD being treated for a risk they do not have, while the OCD, which is the actual problem, goes unrecognised.
It also works the other way. Someone who is genuinely suicidal may have read about intrusive thoughts and decided that is what they have, because it is less frightening, and may not get the response they need.
Say so, either way
If it is the second, if you are actually thinking about ending your life, or you believe you might act, say so straight away, in the first email if you like, and we deal with that first. Therapy for OCD is not a crisis service, and I would rather know at the start than discover it in session six. If you are in immediate danger, call 999 or go to A&E; Samaritans are free on 116 123 at any hour.
If it is the first, an intrusive urge you find horrifying and want gone, say that too, and say it plainly, because it is a recognised OCD theme and it is treatable. Separating the two is a routine part of assessment, not an interrogation, and a therapist who knows this theme does it quickly.
What the OCD version looks like
Roughly half of people who have never had a mental health problem report the urge to jump from a height, sometimes called the call of the void. What makes it OCD is what follows: the meaning the thought takes on, and the safety apparatus built around it. Standing further back. Gripping the wheel. Moving the knives. Avoiding being alone with people. And a constant self-monitoring, checking whether you still feel in control, which makes control feel precarious in anybody.
Thoughts and actions run on different systems. The horror you feel is evidence that the thought is landing on somebody it is profoundly at odds with.
What treatment does
For the OCD version, the treatment is CBT with exposure and response prevention. We do not try to establish that you are safe, because the establishing is the compulsion. We map the cycle and withdraw the safety behaviours gradually, by agreement, then get the ordinary things back: the platform, the drive, the kitchen, the quiet room. This theme sits close to harm OCD, and plenty of people have both.
If you are not sure which of the two you are describing, that is fine, and it is exactly what the first conversation is for. There is more on how I treat fear of losing control, and you do not need to have sorted it out before you get in touch.