I think there's a lot that you aren't telling us. You seem to focus a lot on their behavior and on the behavior of their mother (who isn't in the picture, is that right?), but are not giving much of a description of how you or your partner behave towards them, beyond the forceful adjectives like 'push', 'press', and 'drill'. That's a huge element, as it takes two to tango in relationships.

You also speak of them in extremely derogatory terms like "getting them off their ass" or "not letting them freeload like their deadbeat bio mom" or calling them a fucking sociopath??? I can only imagine that they pick up on that lack of respect for them and respond accordingly. Kids aren't stupid.

It seems like you have a lot of unresolved issues that you might be taking out on them and if possible I would echo the other commentor recommending therapy—but for YOU, as an individual.

This could have been written about me by the parents I do not speak to anymore.

You talked an awful lot about your kid.

How are you doing?

Your 18yo sounds like a grown up version of my 4.5 year old. Honestly if you said the arguments were about potty training we’d be talking about the same person.

How were they, when they started living with you full time, with regards to pottying? Difficult? Regressive? Headstrong?

I ask because how you are doing, because I started seeing a therapist for my own struggles with parenting. And it’s probably the best thing I’ve ever done. It really gives a chance to reflect and get honest constructive feedback on how I approach and handle interactions and discipline and whatnot. Most importantly, how to deal with stresses of parenting a difficult kid and not criticize yourself too harshly at every setback.

Please, if you haven’t already, consider a therapist for you, preferably one who specializes in family issues.

Not much to add to the topic, but just wanted to point out that you shouldn't really 'self-diagnose' as you call it. For example 'sociopath' is not really a diagnosis anymore.

The kid's an adult now. In my household that would mean a place to live at long as they are in school full time, working full time, or convince me that their alternative is actually reasonable. You also have a list of basic chores for them that are fair based on an even split. Other than that you get the help you ask for. It sounds like the lesson your kid needs to learn now is how to cope with things after your parents stop micromanaging you and it all falls apart.

To get to that point you have to be willing to let everything fall apart. If they move out to couch surf, or be homeless, or something else, you tell them you love them and if they ever want help you will welcome then back and help them figure things out.

But until they want that, they won't take it.

The only thing I can offer you is that motivation isn't the currency of the ADHD brain. Importance isn't the currency of the ADHD brain. The only currency of the ADHD brain is INTEREST. As in, "Oh, this is interesting to me."

It sounds as if school isn't capturing their interests. Can changes be made so that school is interesting? Harder classes? Different electives? Anything?

And trust me, you don't want unmanaged ADHD behind the wheel of a car. There's a reason we of the ADHD brain have a shorter life expectancy on average, and that's because the deaths that bring down the average are almost all vehicularly related. I'd back off that expectation until the ADHD is under control.

Is there a psychiatrist in play? Medication ought to be lowering the activation energy/removing or easing the barrier-to-action between your child and the things they are interested in and actually want to do, and it sounds as if that isn't happening.

As a parent with ADHD and a parenting coach with lots of experience parenting ADHD children (though none my bio kids; my own bio kid is too young for their ADHD to be any of the known struggles) -- You have to back down, not ride harder. Sure, one of the ways to overcome the barrier-to-action is unholy terror which puts in place fight-or-flight and can get one over the barrier BUT existing in that state endlessly is super duper bad and leads to serious hard burnout and trauma from constantly being The Problem. I know that riding them has been effective thus far, but under the hood, the way it has been effective has done long term harms. As a family, you all need to learn new management and coping skills. You need to stop overfunctioning. Family therapy (which is different in nature than couples therapy or individual therapy) is the direction to go here. ADHD isn't a person's problem, it's a family problem. Especially when it involves a child who need parents to teach and guide them in to how to exist as prosocially as possible with the brain they never asked for but nonetheless were given. You aren't teaching them how to exist with their brain, you are teaching them how to exist with your brain; they don't have your brain. ADHD isn't a malfunctioning neurotypical brain any more than neurotypicality is a malfunctioning ADHD brain. Both are okay and both are different. Think horses and zebras - both okay, both different, both rideable, both with manes and tails, both with hooves, both about the same size, but a zebra is not a malfunctioning horse nor a horse a malfunctioning zebra. A horse cannot teach the zebra how to horse, it would be bad for the zebra.

My own Mother called my ADHD Father some names (deadbeat is the one you chose to call) and when I realized I related to my Father due to same neurotype, I realized two things: (a) my mother would call me a deadbeat too simply because she doesn't know how to coexist with a neurodivergent person and so her response is disgust and shaming and (b) living in the house with her was going to be supremely traumatic to me because she's going to take out her discomfort and ignorance on me in the worst ways. I got out of the house. Your child has not.

Might I suggest that your education come from ADDitude Magazine's webinar series? It is free as a podcast. And I would like to extend an invitation to you to join the How to ADHD Discord as there is a whole parenting section for advice on parenting ADHD children as well as another section called "Hearts asking Brains". You, not having ADHD, would be a heart. And the adult ADHD brains can offer insights you might not otherwise have been exposed to.

I had started to write a lengthy response on mobile before others had commented, but after the conversations which were had, most of that is now unneeded.

The short version is: After high school, if you have any relatives willing to take her in, send her that way. It'll be much better for everyone.

I was a young teenager with depression and had a psychotic break. It was probably the hardest point in my life (I'm now a 36 year old father). Your child sounds like they might be having an extremely hard time computing all the changes they're going though, and possibly having identity issues. It's gotta be hard.

It sounds like you're doing the best you can, I wouldn't be too hard on yourself. One thing my dad did for me when I was younger was tell me if I ever needed anything, if I ever needed an exit because there was stress I couldn't talk about he was there and there would be no questions asked.

If you can't get a word in, maybe write them a letter and let them know how you feel. Let them know that you're concerned, but if they need space then don't worry, just let them know you're there for them. They must be going through something and if they need anything - you're there for them. They are just becoming an adult, I wouldn't dismiss them as becoming like their birth mother or as someone you cannot see eye to eye with, that would drive a wedge between you. They are figuring out who they are and what being an adult is. Life is really hard, and for some people it begins to be hard as soon as our adolescence begins.

It sounds like they are at the point where they don't want to be at home. It also sounds like you are the only one still trying to get through as your partner and kid are both done with each other. Why are you holding on?