ADHD rarely travels alone. The NHS England ADHD Taskforce says ADHD frequently occurs alongside other types of neurodivergence, and that co-occurrence with mental health problems such as anxiety, depression and bipolar disorder is extremely frequent.
NICE also tells clinicians to be aware that adults with a mental health condition, people with a history of substance misuse, and people with neurodevelopmental conditions such as autism may have a higher chance of having ADHD.
Why other conditions matter
In assessment
Many conditions can cause symptoms that look like ADHD, such as poor concentration, restlessness or impulsive behaviour. A good assessment looks at:
- whether ADHD explains your difficulties
- whether another condition explains them better
- whether you have ADHD and another condition at the same time
Mind notes that ADHD symptoms can be mistaken for mental health problems. The reverse can happen too. This is why an ADHD assessment includes a full psychiatric history and a look at your current mental state. See what happens in an ADHD assessment.
In treatment
Other conditions can affect which treatment is safest and most helpful, and in what order. For example, a specialist may want to treat severe depression first, or take extra care when prescribing stimulants for someone with a history of substance misuse. See ADHD treatment.
In daily life
Living with undiagnosed ADHD can take a toll. Mind describes how ADHD can affect mental health through strain on relationships, disrupted sleep, guilt, shame and difficult experiences.
Overview of common overlaps
| Condition | What can overlap with ADHD | What may point to it |
|---|---|---|
| Anxiety | Restlessness, poor concentration, poor sleep | Persistent worry about many things |
| Depression | Low motivation, poor focus, tiredness | Low mood or loss of interest lasting weeks or months |
| Autism | Organisation, social difficulties, sensory issues | Differences in social communication and a need for routine |
| Bipolar disorder | High energy, impulsivity, racing thoughts | Distinct episodes of high and low mood |
| Substance use | Impulsivity, poor concentration | Symptoms that change with use or withdrawal |
| Sleep problems | Poor focus, irritability | Symptoms that improve when sleep improves |
This table is a simplified guide only. Only a professional can work out what’s going on for you.
Anxiety
The NHS describes generalised anxiety disorder (GAD) as a common condition where you often feel very anxious about lots of different things. Symptoms can include restlessness, irritability and trouble sleeping, which can overlap with ADHD.
For some adults with ADHD, anxiety grows out of years of missed deadlines, forgotten tasks and feeling on the back foot. For others, anxiety is a separate condition. Both can need attention. Treatments for anxiety include talking therapies such as CBT and some medicines.
Depression
The NHS says depression is more than simply feeling unhappy or fed up for a few days. It can bring lasting low mood, loss of interest, tiredness and changes in sleep and appetite.
In ADHD, focus and motivation problems are usually lifelong and present regardless of mood. In depression, they tend to come with a change in mood. Many adults have both, and treating one may not fully fix the other.
Autism
Autism and ADHD are both neurodevelopmental conditions, and many people have both. The NHS notes that autism signs can be harder to recognise when someone also has ADHD. It also describes masking, where autistic adults adapt so their signs aren’t noticeable, which can be exhausting.
Both conditions can involve difficulties with organisation, social situations and sensory overload, but for different underlying reasons. If you recognise traits of both, mention this at your assessment, as a separate autism assessment may be worthwhile.
Bipolar disorder
The NHS describes bipolar disorder as involving episodes of mania or hypomania, with symptoms like high energy, racing thoughts, fast speech, reduced need for sleep and impulsive behaviour such as overspending, as well as episodes of depression.
These can look like ADHD. A key difference is that bipolar symptoms usually come in episodes that are a change from a person’s usual self, while ADHD symptoms are long-standing. Getting this right matters because the treatments are different. Tell your assessor about any periods of unusually high mood or very little sleep.
Alcohol and drug use
NICE lists a history of substance misuse as linked to higher rates of ADHD. Some adults use alcohol, cannabis or other substances to cope with restlessness, a busy mind or low mood.
Substance use can also cause symptoms that look like ADHD, and affect whether ADHD medication is safe. Being honest with your assessor helps them make safe decisions. NICE advises prescribers to be cautious with stimulants where there is a risk of misuse.
The NHS says that if you need help with drug use, you’re entitled to treatment in the same way as for any other health problem. You can start with your GP or contact local drug services directly.
Sleep problems
Sleep difficulties are common in adults with ADHD, and some ADHD medicines can make sleep harder. Poor sleep can also cause problems with attention, memory and mood on its own.
The NHS says insomnia usually improves by changing sleeping habits, and advises seeing a GP if changes haven’t helped after a few months or it’s affecting your daily life. There are more sleep tips on the page about living with ADHD.
Dyslexia and dyspraxia
Specific learning difficulties often occur alongside ADHD.
Dyslexia mainly affects reading, writing and spelling. The NHS says an adult dyslexia assessment is not done by a medical doctor, but usually by an educational psychologist or specialist, and most people have to pay for it.
Dyspraxia, also called developmental co-ordination disorder, affects movement and co-ordination. The NHS says people with dyspraxia may also have conditions such as ADHD.
If reading, writing or co-ordination problems are part of your picture, a specialist may suggest a separate assessment. Support at work or study can help with all of these. See living with ADHD.
Support for more than one
- Tell your assessor everything, including past diagnoses, treatments and what did or didn’t help.
- Ask how conditions will be prioritised and which will be treated first.
- Keep your GP informed so your care is joined up.
- Consider talking therapies. The NHS says you can refer yourself to NHS talking therapies for problems like anxiety and depression, without seeing a GP first.
Help with Happy Clinic
Happy Clinic’s consultant psychiatrists assess and treat adult ADHD and can also help with depression, generalised anxiety, panic, social anxiety, OCD and other conditions in adults aged 18 and over. They also offer adult autism assessments. Happy Clinic doesn’t provide psychological therapy or emergency care, but its psychiatrists can advise on therapy options.