Many adults with ADHD also have anxiety or depression. The two can look alike, they often happen together, and one can hide the other. HSE and NHS guidance both say anxiety and depression are common in adults with ADHD.
That overlap is why a proper ADHD assessment does not stop at a symptom checklist. A specialist looks at whether your difficulties go back to childhood and run through your whole life. They also ask whether there have been separate episodes of anxiety or low mood on top.
Having anxiety or depression does not rule you out of an ADHD assessment. The NICE guideline on ADHD says symptoms should not be better explained by another condition, "although there may be other coexisting psychiatric conditions". This page explains how clinicians tell the strands apart, and what that means for treatment. For the core signs themselves, start with signs of ADHD in adults.
Large studies in different countries point the same way.
The NHS adds that people with ADHD are at higher risk of suicide. If you are struggling, the help section near the end of this page lists who to contact.
The HSE model of care describes three possibilities when someone with ADHD has other mental health symptoms. The symptoms may be part of the ADHD itself. They may be a consequence of living with ADHD. Or they may be a separate condition. Working out which applies to you shapes treatment.
Some symptoms appear on more than one list:
So "I can't concentrate" on its own says little about the cause. Timing and pattern say much more.
Years of missed deadlines, lost things and feeling behind can wear people down. The HSE model of care lists procrastination, low frustration tolerance, mood instability, low self-esteem and "needless worrying" as features often seen in adult ADHD. These are not part of the formal diagnostic criteria. The NHS also notes that anxiety and depression can make ADHD symptoms worse.
Sometimes anxiety or depression is a condition in its own right. It then needs its own treatment, not just treatment for ADHD.
The HSE model of care includes a checklist from the UK Adult ADHD Network. It helps clinicians separate ADHD-related symptoms from a separate anxiety or mood disorder. A simplified version:
The checklist adds that a depressive episode is "not routinely" part of ADHD and needs separate treatment.
The biggest clue is usually time. NICE says ADHD symptoms should have begun in childhood and persisted throughout life. The diagnostic criteria (DSM-5) say they should not be better explained by another condition, such as a mood disorder. A depressive episode tends to have a start point. ADHD tends to have always been there, even if it was never named.
NICE says ADHD should only be diagnosed by a specialist with training in ADHD. The assessment should include:
NICE also says a rating scale alone is never enough for a diagnosis. Our guide to what happens at an adult ADHD assessment covers the steps in more detail.
The HSE model of care says identifying other conditions is "an essential part of the ADHD assessment". The clinician decides whether symptoms are part of the ADHD or a separate condition. If they are separate, "the nature and severity of the comorbidity will determine which is treated first".
The last point matters because the HSE lists substance misuse among the main conditions to rule out or treat alongside ADHD.
There is no single order. A 2017 review of adult ADHD and comorbid disorders says guidelines generally recommend treating the most impairing condition first. In the Irish public model, people with more severe coexisting mental illness are treated by their adult community mental health team first. If they improve, they are re-screened and referred on to the ADHD clinic if still positive.
NICE says to offer people with ADHD and an anxiety disorder the same medication choices as anyone else with ADHD. It also says dose changes should be slower, with more frequent monitoring, when anxiety disorders or depression are present.
UK product information for methylphenidate (Concerta XL) says it can cause anxiety, agitation or tension. It can also worsen pre-existing anxiety. Prescribers are told to check for anxiety before starting and to monitor at every dose change. These are reasons for careful monitoring, not reasons to avoid assessment. Our article on what ADHD stimulants actually do covers how they work and their side effects.
The same UK product information lists a diagnosis or history of severe depression or suicidal tendencies as a reason not to use methylphenidate. Product information for both methylphenidate and lisdexamfetamine says people with depressive symptoms should be screened for bipolar disorder risk before starting. That is because stimulants can trigger a manic or mixed episode in some people with bipolar disorder. See our guide to bipolar disorder in adults.
Sometimes partly, often not fully. A 2025 systematic review found ADHD medicines consistently improved core ADHD symptoms in adults with other conditions. Their effects on those other conditions were "more variable". There was some evidence of benefit for certain anxiety disorders. The authors said the evidence was not strong enough to define the best long-term approach.
The HSE checklist makes a similar point. Chronic low self-esteem from ADHD usually improves as symptoms come under control. A depressive episode needs its own treatment, and stimulants are "usually insufficient".
NICE recommends a structured psychological intervention focused on ADHD for adults who need non-drug treatment. It may include elements of cognitive behavioural therapy (CBT). Anxiety and depression have their own evidence-based treatments. For anxiety, see how GAD and social anxiety are treated.
The HSE model of care was published in January 2021. Under it, referral for public adult ADHD assessment goes through your local adult community mental health team. That team assesses for other mental health conditions and screens for ADHD. People who screen positive are referred to an ADHD clinic for a detailed assessment. The model of care says this assessment "must include identification of co-morbidities". Your GP is usually the first step towards that referral.
The NHS says that at a first appointment, the GP will ask how symptoms affect your life. They may consider other conditions that could explain them, such as autism, Tourette's or anxiety. They may then refer you to a mental health professional specialising in ADHD.
If you are thinking about suicide or harming yourself, you do not have to wait for an assessment to get help.
Yes. The NHS lists restlessness, irritability and difficulty concentrating as symptoms of generalised anxiety disorder. Those overlap with ADHD. An assessment looks at whether the difficulties go back to childhood and appear across your life, not just in anxious periods.
Not always. NICE allows for coexisting conditions. If depression is severe, a clinician may treat it first. In the Irish public model, people with significant coexisting mental illness are treated by their mental health team first, then re-screened.
It can. UK product information for methylphenidate says it can cause anxiety or worsen existing anxiety. NICE still recommends the same medication choices for people with anxiety disorders, with slower dose changes and closer monitoring. Talk to your prescriber about any change in how you feel.
You are not alone in that. NICE says girls and women with ADHD may be more likely to receive an incorrect diagnosis of another mental health condition. The HSE model of care describes adults with ADHD being misdiagnosed with conditions such as atypical depression. Our article on ADHD in women looks at why.
You can read about Proco's planned assessment service on our assessments page.
This article is general information, not medical advice. It cannot diagnose ADHD, anxiety or depression. Talk to your GP or prescriber about your own situation, and never stop or change a medicine without their advice.
Reviewed by: Proco Team
Last updated: November 2026