Whatever problem you have, there are necessarily a cure for it. When it comes to mental illnesses, I believe most of them are not so related to genetics apart from obviously pretty genetic disorders like down syndrome or autism. If you examine the mentally sick people carefully enough, most of them loose their mind at a later stage of their life. Be it in puberty or in adulthood, or even at older ages, they were all born happy when they were kids. So most probably, something wrong happened during the process of growth. I don't mean basic growth babies go through by the way. Learning continues until you die. It is very likely that something that musn't happen happened to you or you yourself did something else wrong you are not aware of, which caused you to set up various wrong connections or dopamin addictions in your brain. First of all, you need to increase your awareness regarding those wrong habits. Once you reach this kind of a awareness, the next step is focusing on the solution. After that, you need to take good care of your heath. Most basic brain disorders consist of distorted dopamin reseptors and inflammation. If you masturbate a lot or have sex regularly, do yourself a favor and stop indulging in such activities completely. If you smoke, stop smoking( Of course, easier said than done except that you have such a thing as willpower. Make good use of it. Once upon a time, I too was where you are coming from but finally got out of this stituation -at least, I am about to, very close to eventually getting rid of all of my unnecessary thinking patterns. I started to be able to pick up a good book and finish it cover to cover ). Dopamin addiction also bidirectionally makes those unnecessary connections stronger. So do not hesitate to target most basic part of the problem. After that comes the issue of inflammations. Inflammation inside your brain may slow down the communication between your neurons which yields to things like depression or slow wit. To reduce inflammation I highly recommend that you do intermittent fasting. What else? What about the connections unrelated to sex or food addiction? Maybe certain traumas, accidental negative thinking which transformed into obsession. What are you gonna do for these? I highly recommend meditation.Make it a daily habit. Meditate, at least, one hour a day. Half hour non-reactive meditation and half hour concentration exercise. Let me explain what each of them means.

In non-reactive meditation, you'll carefully observe your thoughts without reacting to them. As soon as you recognize your mind is trying to understand something or find a solution to a problem, gently stop the thought and keep watching your thoughts. Each time you notice an interesting subject or extremely distressing thought, resist the temptation to engage in these thoughts. This way, you'll have weaken those unnecessary connections even if you haven't completely severed those connections.

Now, I assume you have learnt to not be affected by the wrong programming in your subconscious mind.
At this stage after that, you have already succeeded the pretty essential part of the mental development process. You'll be more present. You'll be able to use your prefrontal cortex responsible for your conscious thinking skill much better since you will have learnt to not engage in irrelevant automatized thinking patterns.
Let's pass to the concentration exercise. Since you have already weakened those not-so-needed associations,
now, we can pass to truly pruning these. In concentration meditation, you'll simply say "beep" from your mind each time a thought appears inside your mind to cease it completely. You can also pinch yourself to stop the thought. Since your brain is more receptive to pain, this will increase your presence. This will truly teach you to pay attention to Now instead of a lot of worrying or fantasizing without taking initiative at all.

This way, you are constantly disabling your brain's default networking mode. What is the brain's default networking mode for? It is just random chattering which usually makes no sense. It was given to us, to regularly use the previously learned information or algorithms(known steps leading to the solutions we face) without having to think consciously. Quite automatic. Still serves a purpose yet our mind is not all about it. It is usually comprised of the track of your previous thinking. And it is very dangerous if you program it wrong either deliberately or due to the things you can't control that befall you. Do these exercises regularly, you'll recover. Your brain's default networking mode will end up closing down. Thus, you'll decide which predefined algorithm you will use with your conscious mind as if yourself have put it with your hand. You can program your subconscious mind faster and more easily instead of constantly having to rely on automatic thoughts that serve no purpose. Your subconscious mind will be the servant of your conscious mind instead of the other way around.

And final warning : You will necessarily have setbacks from time to time. This is pretty normal. Just do not give up. And keep trying different methods the times when you understand that the systems you are using do not work anymore. As Albert Einstein said, definition of insanity : doing same things over and over and expecting different results. Hope this helps   (By the way, I am aware of consciousness being beyond science and that you are not all about your brain but I don't wanna confuse a beginner with this kind of "mystery")