Homepage Looking for help? Common conditions

Common conditions

People with mental illness, learning disability, dementia and related conditions should have good treatment that meets their needs and respects their rights. We do our best to help make sure this happens.

The law often talks about people with a "mental disorder". That term can cover lots of different conditions.

Here you can find an overview of some of the most common conditions. 

Many people will have more than one condition, and many more will have a diagnosis that is not listed here.

Of course, every person is an individual and whatever condition they are diagnosed with is only part of their identity.

Mental illness

Around one in four people experience mental illness at some point in their lives.

For some people, a mental illness is a one-off: something that happens once and passes. Other people have many episodes of mental illness.

Here you can find an overview of some of the most common conditions. Many people will have more than one condition, and many more will have a diagnosis that is not listed here.

Of course, every person with a mental health problem is an individual; every person's experience of, and recovery from illness will be different.

Most people with a mental illness are able to live fulfilling and satisfying lives.

Personality disorder

Personality disorders, like personalities, can be complex and difficult to define.

People with personality disorders often find it difficult to live with themselves, or with other people.

However, there are treatments available which can make a difference to people with personality disorders.

To learn more about the different types of personality disorders and the treatments that are available, visit the Royal College of Psychiatrists website.

Acquired brain injury & alcohol-related brain damage

Our brains play an important role in our behaviour, feelings, and understanding of the world.

If the brain becomes damaged, people may experience the same symptoms as people with mental illness, dementia, or learning disability. As a result, they are often subject to the same laws, such as the Mental Health Act and the Adults with Incapacity Act.

Acquired Brain Injury

Acquired brain injury can occur as a result of a trauma, such as an accident, or after certain illnesses, such as a brain tumour or a stroke.

For more information on the effects of acquired brain injury and options for rehabilitation and support, visit the Headway website.

Alcohol-Related Brain Damage (ARBD)

Harmful use of alcohol and dependence on alcohol are common. These are not "mental disorders" under the law in Scotland and do not come directly within our remit. But some people suffer brain damage from harmful alcohol use.

Damage can have several causes, including direct damage from alcohol, vitamin deficiency, and head trauma. These can affect memory, judgement, and behaviour. Over a long period of time, heavy drinkers may develop various types of brain damage.

To find out more about the symptoms, diagnosis, and treatment of ARBD, visit the Alzheimer Society's website.


We all tend to get more forgetful as we get older. But dementia is different.

It is a brain disease which often starts with memory problems, but goes on to affect many other parts of the brain, producing:

  • difficulty coping with day-to-day tasks
  • difficulty communicating
  • changes in mood, judgement, or personality

It usually gets worse over time. With dementia you tend to have to rely on other people more and more as the illness progresses. It is much more common in older people, but can start as early as 40.

About one in every 20 over 65s have dementia, and by the age of 80 about one in five will have some degree of dementia.

Alzheimer's disease is the most common cause, but there are also other forms, such as vascular dementia, lewy-body dementia, and fronto-temporal dementia.

If you are worried about your memory, see your doctor. They can do a simple memory test, a physical examination, and order blood tests. If needed, they can then refer you to a specialist, who will test your memory in more detail and arrange a brain scan.

This information is supplied by the Royal College of Psychiatrists. You can learn more here, and you can find more information and support from Alzheimer Scotland.

Learning disability

People with learning disabilities have a significant, lifelong condition that started before adulthood (age 18), that affected their development and which means they may need support.

They may need help to understand information, learn skills, and cope independently.

With the right support, people with learning disabilities can live full and happy lives and make a meaningful contribution to our communities.

What causes learning disability?

It is not always possible to say why someone has a learning disability. There are many different types of learning disability. Most learning disabilities are caused by the way the brain develops - before, during, or soon after birth.

Before birth:

  • Things may happen to the central nervous system (the brain and the spinal cord)
  • The mother may have an accident or illness while she is pregnant
  • A parent may pass on particular genes to the baby
  • The genes may develop in a particular way while the unborn baby develops.

During birth:

  • The baby may not get enough oxygen
  • The baby may be born prematurely

After birth:

  • The baby may develop an early childhood illness such as encephalitis or meningitis
  • The baby may fall victim to a physical accident

Genetic causes of learning disability

Fragile X syndrome and Down's syndrome are the two most common genetic causes of learning disability.

Although Fragile X syndrome is the most common genetic cause of learning disability, not everyone with this condition has a learning disability. If they do, the learning disability could be mild, moderate or severe. People with Fragile X syndrome may also have problems with concentration and communicating with, or relating to, other people.

About 60,000 people, or one in every 1,000 babies, in the UK have Down's syndrome. This is caused by the presence of an extra chromosome. Everyone with Down's syndrome has some kind of learning disability.

Profound and multiple learning disabilities

People with profound and multiple learning disabilities (PMLD) have a profound learning disability, more than one disability and great difficulty communicating. They will need full-time support with every aspect of their lives - including eating, drinking, washing, dressing, and personal care.

For more information and support for people with profound and multiple learning disabilities and their families, visit the PAMIS website.


Autism is a lifelong developmental disability that affects how a person communicates with, and relates to, other people. It also affects how they make sense of the world around them.

It is a spectrum condition, which means that, while all people with autism share certain difficulties, their condition will affect them in different ways.

Some people with autism are able to live independent lives, but others may need support; some people with autism may have accompanying learning disabilities and need specialist support. People with autism may also experience over- or under-sensitivity to sounds, touch, tastes, smells, light or colours.

Asperger syndrome is a form of autism. People with Asperger syndrome are often of average, or above average intelligence. They have fewer problems with speech, but may still have difficulties with understanding and processing language.

Thank you to National Autistic Society Scotland for this definition, copyright 2012. You can find out more about autism and asperger syndrome at their website.