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Britain & the wider world: 1745 -1901
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Psychology
12 Dec 2025
589
4 pages
Ever wondered why some people can't stop checking locks or washing their hands? The biological approach suggests that... Show more
Twin studies provide compelling evidence that genetics play a major role in OCD development. Billet et al's research showed that identical twins were more than twice as likely to both have OCD compared to non-identical twins, which makes perfect sense if you think about their shared DNA.
However, there's a massive problem with causation vs correlation. Scientists usually spot these biological differences only after someone's already been diagnosed with OCD. It's like trying to work out whether the chicken or the egg came first - we can't be certain if brain differences cause OCD or if having OCD changes the brain.
The reductionist criticism is particularly damaging to this approach. Saying OCD is just down to faulty genes or wonky brain chemistry ignores huge factors like stress, trauma, and learned behaviours that clearly influence the condition.
💡 Remember Correlation doesn't equal causation - just because two things happen together doesn't mean one causes the other!
Your genes might actually predispose you to OCD through two key culprits. The COMT gene normally keeps dopamine levels in check, but when it's mutated, dopamine floods your brain. This excess creates overactive neurons that drive those repetitive OCD behaviours you can't seem to stop.
The SERT gene works differently but causes equal chaos. When this gene malfunctions, your brain can't transport serotonin properly, leaving you with critically low levels. Since serotonin usually keeps you calm by inhibiting brain activity, having too little means your neurons fire away uncontrolled.
Think of it like faulty volume controls on your brain's music system. High dopamine cranks up anticipation and reward-seeking, whilst low serotonin removes the 'chill out' button entirely.
💡 Key Point Both gene mutations mess with neurotransmitter balance, but in opposite ways - one creates too much activity, the other removes natural calming mechanisms.
The biological approach gives us concrete, measurable explanations for OCD that can lead to effective medical treatments. Brain scans and genetic testing provide hard evidence that this isn't just 'being fussy' - it's a genuine medical condition with physical roots.
Yet this approach struggles with the nature vs nurture debate. Real-world OCD often involves environmental triggers, traumatic experiences, and learned responses that pure biology can't fully explain. Many people have the genetic markers but never develop OCD.
The most realistic view combines biological vulnerability with environmental factors. You might inherit the genetic 'loaded gun', but life experiences pull the trigger. This explains why treatments often work best when they combine medication (targeting biology) with therapy (addressing thoughts and behaviours).
💡 Bottom Line Biology provides the foundation, but psychology and environment shape how OCD actually develops and presents in real life.
The orbitofrontal cortex (OFC) acts like your brain's alarm system, detecting threats and sending worry signals to get you moving. Normally, the caudate nucleus steps in like a sensible friend, suppressing unnecessary alarms once you've dealt with the problem.
But in OCD brains, this system breaks down catastrophically. The caudate nucleus becomes underactive or faulty, failing to switch off those worry signals. It's like having a fire alarm that won't stop ringing even when there's no fire.
This creates a vicious cycle where the OFC keeps screaming about threats, driving you to perform compulsions that never actually silence the alarm. Your brain literally can't feel that the threat has passed, explaining why people with OCD know their behaviour is irrational but can't stop it.
💡 Think of it Like a broken thermostat that can't tell when the house is warm enough, so the heating never switches off.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Ever wondered why some people can't stop checking locks or washing their hands? The biological approach suggests that OCD might be literally written in our genes and brain chemistry, making it as physical as any other medical condition.
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Twin studies provide compelling evidence that genetics play a major role in OCD development. Billet et al's research showed that identical twins were more than twice as likely to both have OCD compared to non-identical twins, which makes perfect sense if you think about their shared DNA.
However, there's a massive problem with causation vs correlation. Scientists usually spot these biological differences only after someone's already been diagnosed with OCD. It's like trying to work out whether the chicken or the egg came first - we can't be certain if brain differences cause OCD or if having OCD changes the brain.
The reductionist criticism is particularly damaging to this approach. Saying OCD is just down to faulty genes or wonky brain chemistry ignores huge factors like stress, trauma, and learned behaviours that clearly influence the condition.
💡 Remember: Correlation doesn't equal causation - just because two things happen together doesn't mean one causes the other!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your genes might actually predispose you to OCD through two key culprits. The COMT gene normally keeps dopamine levels in check, but when it's mutated, dopamine floods your brain. This excess creates overactive neurons that drive those repetitive OCD behaviours you can't seem to stop.
The SERT gene works differently but causes equal chaos. When this gene malfunctions, your brain can't transport serotonin properly, leaving you with critically low levels. Since serotonin usually keeps you calm by inhibiting brain activity, having too little means your neurons fire away uncontrolled.
Think of it like faulty volume controls on your brain's music system. High dopamine cranks up anticipation and reward-seeking, whilst low serotonin removes the 'chill out' button entirely.
💡 Key Point: Both gene mutations mess with neurotransmitter balance, but in opposite ways - one creates too much activity, the other removes natural calming mechanisms.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The biological approach gives us concrete, measurable explanations for OCD that can lead to effective medical treatments. Brain scans and genetic testing provide hard evidence that this isn't just 'being fussy' - it's a genuine medical condition with physical roots.
Yet this approach struggles with the nature vs nurture debate. Real-world OCD often involves environmental triggers, traumatic experiences, and learned responses that pure biology can't fully explain. Many people have the genetic markers but never develop OCD.
The most realistic view combines biological vulnerability with environmental factors. You might inherit the genetic 'loaded gun', but life experiences pull the trigger. This explains why treatments often work best when they combine medication (targeting biology) with therapy (addressing thoughts and behaviours).
💡 Bottom Line: Biology provides the foundation, but psychology and environment shape how OCD actually develops and presents in real life.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The orbitofrontal cortex (OFC) acts like your brain's alarm system, detecting threats and sending worry signals to get you moving. Normally, the caudate nucleus steps in like a sensible friend, suppressing unnecessary alarms once you've dealt with the problem.
But in OCD brains, this system breaks down catastrophically. The caudate nucleus becomes underactive or faulty, failing to switch off those worry signals. It's like having a fire alarm that won't stop ringing even when there's no fire.
This creates a vicious cycle where the OFC keeps screaming about threats, driving you to perform compulsions that never actually silence the alarm. Your brain literally can't feel that the threat has passed, explaining why people with OCD know their behaviour is irrational but can't stop it.
💡 Think of it: Like a broken thermostat that can't tell when the house is warm enough, so the heating never switches off.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
2
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
App Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology