There is a lot of controversy around the causes of autism and Asperger's Syndrome, there are many persistent myths around the causes of autism and Asperger's, and around autism and Asperger's in general. I will discuss these first. (Recently Asperger's Syndrome has stopped being used as a diagnostic term, everyone given a diagnosis is diagnosed with autism spectrum disorder now, with low-functioning autism at one end of the autistic spectrum, and those who would have been diagnosed with Asperger's Syndrome, would now be on the high-functioning end of the autistic spectrum)
Myth 1: Autism is caused by vaccinations
Back in the late 1990's a flawed research study was carried out, it involved 12 children who weren't randomly selected and it claimed to find a link between the MMR vaccination and autism. This was false. There have since been many large scale well carried out studies done which disprove this research. The reason this myth is thought to continue to persist is because the vaccination happens about the age of 2, and because autism is a social-developmental difficulty it is only really noticed around the age of 2-2.5 years old when the child is beginning to become more mobile and mix with others more, and talk more, and there are certain milestones which would be expected at this time which may become evident that they aren't happening, and sometimes a child may seem to have been developing well and then regressed in their development about this time if they are on the autistic spectrum. This is a case of assuming the MMR vaccination which came just before the parents noticed the child seemed to be developing differently - for example regressing, was the cause of the regression, rather than just being something that happens at about the same time. It is like someone assuming that Thanks Giving caused Christmas, the two things happen near each other, one doesn't cause the other.
Myth 2: Autism is caused by 'refrigerator parenting'
In the early days of autism research it was felt that autism was caused by 'cold' parents, parent who didn't display love and affection to their children. It is true that when a child has a parent who shows very little love and affection, who doesn't engage with their child, and who is neglectful that child can develop showing signs similar to autism, but they don't have autism, they may have developmental delays, they may have emotional or behavioural difficulties. This is why when parents approach the Child and Adolescent Mental Health Services (CAMHS) to seek an autism diagnosis the first thing CAMHS want to know is how are the family relationships, what is family life like, how does the child present in school. They want to know whether the child behaves the same in all areas of their life and if not why not. They also want to know whether the child has been the way they are displaying pretty much since birth.
This myth about autism isn't a helpful one, it is a dis-empowering myth, and one that can make perfectly good parents believe the way they raised their child is somehow to blame for the child having autism. This can lead to parents experiencing guilt and a belief that perhaps they didn't love their child enough, all of which is false.
Myth 3: Autism is a childhood form of schizophrenia or psychopathy
Again, in the early years of autism research it was called 'infantile psychosis' and because those with autism can show signs like withdrawal which are similar to schizophrenia it was thought maybe the two are linked. It is now known that the two conditions aren't connected, someone could have autism and schizophrenia, but this wouldn't be due to both being connected it would just be someone who happens to have both conditions. As a parenting worker I have met parents who believe their child is a psychopath due to lacking feelings. Again this is a myth, firstly autistic people don't 'lack feelings', they may make different connections to others and so not get emotional about the same things, but they still care. As someone with autism spectrum disorder this is one of the most difficult things to explain. I want everyone to have the best life they can - I care, I love my wife - but I'm not very good at showing that love, or in the past realising I need to 'show' the love, it is something I 'know', I can hear bad news and not be bothered by it, I can be in situations others find distressing or scary and not be bothered, but I can be taken by surprise by intense emotions which overwhelm my senses the same as other sensory input - like when giving my speech on my wedding day, and taking about a video of my grandad which I had recorded and was just about to show other relatives at his memorial following his death. In these situations it made no logical sense to me to be crying (with happiness/upset) yet that is what happened. I also now cry at romantic films (I never used to when I was younger, I now cry at films etc far more than my wife). As a child and young adult, and still in many situations I can appear cold and harsh and uncaring. I struggle to remember that others seem to need me to behave a certain way so that they understand that I care. I will be blunt with people, but to me I am being caring - I am being honest etc. Me not hugging my wife doesn't mean I don't love her, yet from her perspective me not hugging her makes her start to worry about whether I love her, whether I find her attractive etc., which to me is illogical to connect the two things. The fact I am with her means I love her, because if I didn't I would leave. These traits can lead to some people thinking a child may be a psychopath when they are older. Again someone could grow up to be a psychopath and have autism, but the two aren't connected, they are just someone who has both conditions.
Some other myths about autism include:
Myth 4: Autism is a mental illness
Autism is a neurological condition, someone with autism is born with their brain processing information differently to 'neuro-typical' people. A mental illness is something which develops during life for some reason, for example someone could develop anxiety, or obsessive compulsive disorder, or depression from life events. People aren't born with obsessive compulsive disorder, or depression, or anxiety, or phobias, or post-traumatic stress disorder, all of these develop from a mixture of an individual's thinking style which they have learnt, and from their beliefs, mixed with specific environmental conditions, and in rare cases from their biological functions - for example; following pregnancy in some people significant hormonal changes can occur which can lead to someone becoming depressed, although in many cases the biological changes in depression and anxiety conditions are the result of being depressed or anxious, not the cause. Long term depression or anxiety conditions change the brain neurologically, just like learning anything does, but if someone with depression or anxiety learns a new way to interact with the world around them which doesn't lead to depression or anxiety, then neurological changes will happen in this new way and the person can find they respond to situations without becoming depressed or anxious (it is natural for depression and anxiety to happen, but the aim of therapy is to help someone so that these only happen at the appropriate times, like being anxious in situations where you are genuinely at risk of harm).
Myth 5: Autism can be cured
This is the big difference between mental illness compared to autism, autism is something you are born with and something you have your whole life, not something you develop during your life, autism can't be cured because it is a part of who the autistic person is, not something they developed. This isn't to say those with autism can't be helped, they can, but regardless of how much better they get - for example; at socialising, or recognising people's emotions, they will still have autism. And just because mental illness like depression and anxiety problems are something which has been developed during life - for example; someone could have spent their childhood with a neglectful parent, or a parent who always told them they were a failure, or a parent who suffered with depression or anxiety and so inadvertently taught this way of thinking about the world to their child, or if could have developed due to a life event like a relationship break-up, or accident, etc., or any number of other causes - this doesn't mean that they are easy to treat or overcome, just that they can be treated and 'cured', whereas autism can't be 'cured'. It could be that at some point in the future scientist develop a way of curing conditions like autism, but the question is whether that is a good thing or not, and whether we should 'cure' autism if it ever becomes possible. I have worked with thousands of parents and I have met my fair share of parents who wish they had a cure for their child's autism. And often this cure is being sought because it would make things easier for the parent, or because the parent perceives greater suffering for their child if they grow up 'different', or because the parent feels guilt and blames themselves for the child having autism, and so they want to get rid of the autism, to get rid of their guilt, or they don't want to have a 'disabled' child.
Many people with high-functioning autism that I have met and spoken with wouldn't want to be 'cured' they feel that if they didn't have autism then they wouldn't be who they are. That autism is a part of who they are, not something that can be separated from who they are. This doesn't mean they don't wish they didn't have some of their issues, and it is in these areas that they need help and support to address, like learning how to interact in social situations, or learning how to manage overwhelming sensory input, or learning how to keep calm when they can't immediately exit from a situation, rather than getting angry or anxious and 'kicking off' in the situation, etc. People I have worked with - specifically when I used to work in residential care homes, who have low-functioning autism have often been as happy as any other population of people I have met. Just because they perhaps don't talk, or all they do all day is sit making a repetitive gesture or behaviour, and they are never going to be able to lead a life without being looked after, and are probably never going to be able to work, or achieve educational attainment, doesn't mean they are unhappy with the life they have.
People with and without autism have varying levels of educational attainment, some work, some don't, some can get jobs, others struggle to get work, some struggle to hold down work, other are almost never out of work, some get bullied, others don't, some have anxiety or depression, or other mental illnesses, others don't. When someone thinks an individual needs 'curing' of their autism because if they didn't have autism they wouldn't be different and so wouldn't be discriminated against, or bullied, and would be better at socialising, or holding down a job, and wouldn't need looking after by a carer their whole life, this thinking is faulty because in reality many of these issues could still happen to them even if they weren't autistic.
I have met people who get discriminated against because they are shy and so don't talk about much at work, and unlike someone with autism who can say they are being discriminated against, and can do something about it because (in the UK at least) there are laws to protect against discrimination which someone with a diagnosed problem can use to take action, the person with shyness can't take action against the employer, yet they may be discriminated against just as much, and may be experiencing distress just as much. I have met people who have no education, who don't have autism, some have still been successful with getting work, others haven't. I have worked with many children and young people and some adults who have faced bullying who don't have autism. The thing about bullying is that bullies will often find something to single the individual out even if they have nothing 'wrong' with them. So someone with autism may get bullied because they have autism, but someone without any problems may get bullied because the bully gives them a label, perhaps based on a one-off event which occurred, like maybe they were called a specific name and that is now being used as a way into the bullying, or maybe they made a mistake in class, or maybe they are bullied because they live in the wrong part of town. The more obvious a difference is, the more likely that will be used for bullying - so if someone is depressed, or anxious, or gets upset quickly, or gets angry quickly, or struggles with learning, or is top of the class, or is fat or skinny, or unfit, etc., this become easy for bullies to try to use as a way to bully that individual. I know parent's generally want to protect their children from harm and want their children to be happy, but 'curing' them of autism isn't necessarily a route to making the child happy, and those with autism have different ways of thinking about things, so if the child is loved for being who they are, then if they were 'cured' of their autism, they would also have a totally different way of thinking to what they had with autism, and it would change their personality, interests, creative perspectives, and many quirks (as everyone has) which makes them who they are. In my own life I have had people make assumptions based on their thinking, who will decide that I would be better off with a cure because then I wouldn't have got depressed and started having suicidal thoughts from discrimination in work, and it is likely true that if I wasn't me I wouldn't have been discriminated against, and I didn't like how I felt at that time, but I wouldn't have wanted a 'cure' for me being me, I wanted help to stop the discrimination and address the situation. I have had people say if I was 'cured' I wouldn't be lonely, they make this 'lonely' assumption based on me often being alone (I have a wife, and so nowadays I'm not alone, but I rarely see anyone other than my wife). They imagine what they feel like when they are alone for long periods of time, and assume I must feel the same as they do when I'm alone. The reality is one of my favourite things is to be alone, so unlike them I am very comfortable with my own company. This is one of the most common reason's for 'neuro-typical' people wanting an autism cure, because they imagine the autistic person's life and experiences from their perspective of what they think it would be like to be in that situation, rather than accepting that the autistic person may well have a totally different perspective and may be perfectly fine with how they are. Another example of this from my life was when my first marriage ended. When my wife said it was over, I checked to make sure she was certain that is what she wanted, and I walked away. I had one incident of being upset which was when I left the flat for the last time with the last of my belongings, as I walked away from the flat and turned and looked back and saw my wife crying at the front door, I cried because I was aware it was final, this was the last time I was likely to see her, and it was definitely the end. Within minutes I was fine and was getting on with my life, but others around me were adamant that I should be sad, that I should be angry, that I should be going out and getting drunk 'drowning my sorrows' and I should be 'out on the pull'. They said I was repressing my anger and sadness, I was trying to 'bottle it all up', which isn't what I was doing. I genuinely accepted she had made her decision, and we have moved on. I didn't have anger, and other than the sadness I experienced when I last left the flat I didn't have any sadness, I didn't feel any need or desire to 'drown my sorrows' or to 'find' anyone else. Being a marriage which ended I did question myself at the next few anniversaries about whether I had done the right thing walking away so easily, and whether I should have stayed and argued that we shouldn't split up, but I'm someone who checks people definitely want to make the decision they are making, and then accepts that decision. I'm not someone who will force someone to think a certain way, and if I had 'made' her want to stay with me then I would see that as unethical and I could be forcing someone I loved to be in a relationship they don't want to be in, which goes against them having happiness.
So what causes autism?
The causes of autism aren't fully known. There is variety in those with autism, from high-functioning, to low-functioning. As it is something people are born with it is clearly genetic, but how it expresses differently is currently unknown. It could be that genes associated with autism are expressed differently in the presence of other genes, or it could be they are expressed differently in the presence of certain levels of certain hormones during birth, and some of the differences in how it is expressed could be environmental, like how the child is raised. It is likely to be a mixture of all of these elements. One question is why does autism continue to persist? This may be because it has benefits for society when someone is on the high-functioning end of the spectrum. Someone with high-functioning autism is likely to be very good at focusing on one task and obsessing about that one task and that one subject, so they manage to achieve things others don't have the time, focus or patience to achieve, like maybe becoming obsessed with how arrows travel through the air, and wanting to know why an arrow travels as it does, and what would make it travel further and more accurately. Someone with high-functioning autism may focus on this thought for years until they develop an arrow which is more efficient and better than other tribes arrows, which helps the tribe survive and gives the autistic person an advantage to the tribe. It could be that the downside is some people are born with low-functioning autism which means they require more care, but may not contribute to the tribe. This is a similar argument to one I remember learning about schizophrenia when I worked in mental health homes. That schizophrenia is genetic, and at it's worst (and without medication etc) it isn't particularly helpful, but for some people before it develops into schizophrenia they have incredible creativity and connections of thought which others generally don't have. With schizophrenia it is something which some people have a pre-disposition for it, and often a life event or situation triggers the schizophrenia, this could be puberty or a traumatic or stressful experience etc., it is something the person has the genes for, but to turn on the epigenetic expression for the person to have schizophrenia usually takes a trigger.
There are questions about why more people have autism nowadays. The currently thought reason for this is that there aren't more people with autism, just less stigma, so more people are comfortable seeking diagnosis, and better ability to diagnose autism. There are also more females being diagnosed with autism than their used to be. It used to be thought that autism was more of a male issue, and it may have a slightly more male bias - although with time it may turn out this is incorrect, but now it is recognised that females and males can have autism, it is just expressed differently in females to males. For example I think females may find emotional sensory overload more of an issue than males, but this isn't so easily picked up because people seem to think those with autism don't have feelings and don't get emotional, so in the past if a female was getting emotionally overwhelmed psychologists and psychiatrists are likely to assume the problem is something else, not autism.