You’ll never be 100% sure if a patient has bipolar, ADHD, or both, but we’ll get you as close as we can. 

Publication Date: 11/18/2024 

Duration: 17 minutes, 24 seconds 

KELLIE NEWSOME: Distracted. Hyperactive. Irritable. Impulsive. Wait a minute. Is this a list of DSM symptoms for ADHD or hypomania? Let’s find out.  

Welcome to the Carlat Psychiatry Podcast, keeping psychiatry honest since 2003. 

CHRIS AIKEN: I’m Chris Aiken, the editor-in-chief of The Carlat Psychiatry Report.  

KELLIE NEWSOME: And I’m Kellie Newsome, a psychiatric NP and a dedicated reader of every issue. Your patient is a 24-year-old woman with bipolar II who recently came out of a mixed episode. Although her mood symptoms have cleared, she is still easily distracted easily, has difficulty organizing her work, and often forgets important tasks. She read about ADHD online and asks if she can have a stimulant to help her focus.  

CHRIS AIKEN: ADHD and hypomania share many symptoms in common: distraction, hyperactivity, impulsivity, irritability, and excessive talking. So, how do you tell them apart? The usual advice is that the symptoms are episodic in bipolar disorder and continuous in ADHD, and while that makes for a great theoretical construct, it’s a little harder to apply in practice. It’s not always clear cut when episodes begin and end; cognitive problems are common in bipolar even when the mood problems go away, and moody or affective temperaments are common in ADHD, and these can look a lot like bipolar. But the stakes are high here because stimulants are used as the animal model for mania, so we don’t want to give them out on a whim. So come along on this deep dive, and by the end of it, you’ll have a much better idea of what to do when patients resent with symptoms of bipolar and ADHD. 

KELLIE NEWSOME: There are four possibilities in these cases – they either have bipolar, or ADHD, or both, or they could have none of the above. ADHD and bipolar disorder can occur together, and they do so in 10-20% of bipolar patients, but remember that ADHD is a neurodevelopmental disorder that doesn’t always continue in adulthood, so if we’re looking at adult bipolar only half of those cases will continue to have ADHD, which brings the overlap down to 5-10%. On the other hand, bipolar disorder causes symptoms that mimic ADHD, and the rates of false positives are high here. Studies find that if you just gave a screening instrument for ADHD to people with bipolar, up to half of them would screen positive, way more than 10%, so we don’t recommend that route to the diagnosis. And how do they know these are false positives? They follow it up with a structured interview for ADHD, which is a much better strategy (Torres I et al., Acta Psychiatr Scand 2015;132(5):389-399). 

Even a classic ADHD symptom like excessive daydreaming can also be a sign of bipolar. In a large NIMH trial, “Trait daydreaming” was one of the top 3 signs that differentiated unipolar depression from bipolar depression. These patients go about their daily routines while carrying on Walter Mitty-like fantasies in their heads as if they have multiple trains of thought at the same time. They may be having small talk at the checkout line while writing the great American Novel in their head. There’s a lot more overlap in the temperaments of ADHD and bipolar, but first, a preview of the CME quiz for this episode. Earn CME for each episode through the link in the show notes.  

TRUE or FALSE: Affective temperaments are common in both ADHD and bipolar disorder. 

CHRIS AIKEN: There are at least three reasons you can get a false impression of ADHD in a bipolar patient: symptom overlap, temperamental differences, and cognitive problems that can build up as the bipolar illness becomes more chronic. Let’s go through those three one by one. 

First is symptom overlap. All you have to do is read the criteria for mania, and you’ll see it lists things like irritable, distracted, hyperactive, overly talkative, impulsive, which are also all common symptoms of ADHD. Now in mania, these symptoms are more intense, but during hypomania, they may look just like ADHD. The textbooks tell us that the difference is clear: if the symptoms are episodic and resolve with time, then it’s bipolar; if the symptoms are steady throughout the length of time, it’s ADHD. But, the second reason for a false impression of ADHD is going to make a mess of that clean distinction, and that is temperament. Bipolar, it turns out, is not just an episodic illness. For many people, the manic-depressive symptoms bleed into their temperament, and those temperamental differences cause cognitive problems that can look just like ADHD. The problem here is that temperament and ADHD both follow the same time course. They are traits that are constant throughout life and can be traced back to the preschool days. Temperament affects a person’s emotions, behavior, and thinking. So, when a patient says they are always distracted, daydreaming, and disorganized, it’s hard to know if that is ADHD or one of the affective temperament. There are four effectivetemperaments that are seen more often in patients with bipolar disorder – as well as in their relatives, and I will describe them here with each of the moods that they match up with because each one is thought to match up with a particular bipolar mood. 

There’s dysthymic (which is a temperamental depression), hyperthymic (a hypomanic temperament), irritable (which matches with a mixed state – where depression and hypomania overlap), and finally, cyclothymic (which is like a temperamental form of ultrarapid cycling). Around 50% of people with bipolar disorder have one of these temperaments. Now savvy listeners might be thinking, Yeah, I get it that the hyperthymic temperament can make people distracted, impulsive, and restless, and cyclothymic can make people disorganized, inconsistent, and scatter their priorities… but don’t these temperaments come with a lot of mood symptoms? And wouldn’t that make it easy to tell them apart from ADHD? No, pay attention because this is where the overlap gets very confusing. I just said about 50% of people with bipolar have an affective temperament. Well, 40% of adults with ADHD also have an affective temperament. Adults with ADHD, even more than children with ADHD, are more likely to endorse symptoms of cyclothymic and irritable temperaments, but also hyperthymic and dysthymic ones. Try it out for yourself. You can take the temperament test on my website chrisaikenmd.com/tempsa. The overlap between affective temperaments and adult ADHD is so striking that it has led some psychiatrists, like Nassir Ghaemi, MD, to suggest that most cases of adult ADHD are really due to these moody temperaments. To drive this point home, Dr. Ghaemi and colleagues published a paper last year where they looked at long-term outcomes in patients with cyclothymia who were prescribed amphetamines for ADHD at the Tuft’s Mood Clinic. The meds helped their cognition a little – about 24% – but for about 1 in 3 patients, their mood worsened overtime on the amphetamines, much higher than in a comparison group. The overlap of temperament and ADHD doesn’t stop here. Temperamental differences are part of human nature they are not just part of bipolar. Some are more focused, and some tend to wander; some plan ahead, and others live in the moment. ADHD is supposed to be an inborn disorder of hyperactivity, impulsivity, and inattention, but if someone has a cognitive style that doesn’t fit well with the demands of their work or school, it can look a lot like ADHD, even though it's just a difference in the bell curve of their cognitive style. In practice, it’s very difficult to tease apart temperamental differences from true ADHD – whether they have bipolar disorder or not. It’s tempting to say that if the moody aspects of the temperament are more prominent, it's probably an affective temperament, or if they have a family history of bipolar disorder, it's probably an affective problem and not ADHD. But I’ve been fooled many times. I’ve seen patients that I was convinced had cyclothymic disorder, and I treated them with lamotrigine with no difference, only to switch to methylphenidate and have it change their lives. And I have seen it go the other way as well, so I don't have great guidance for you as well on how to tease apart this diagnosis and what to do about it other than to recognize that these moody temperaments are much more common in people with bipolar disorder, and they might lead to a false positive of ADHD. 

KELLIE NEWSOME: So far, we’ve covered two reasons for false positives: the overlap of manic and ADHD symptoms and the continuation of those symptoms at a temperamental level, especially as cyclothymic or hyperthymic temperaments. The final reason for a false positive is that cognitive problems are common in bipolar disorder, and for 30-60% of people with bipolar, those cognitive symptoms continue even after their mood episodes have resolved. Here, there is a way to distinguish it from ADHD. In true ADHD, the cognitive symptoms start in early life. They may get better or stay the same in adulthood, but they don’t get worse with age. In bipolar, the cognitive symptoms start after the mood problems, and they get worse with time. In fact, the top predictor of cognitive symptoms in bipolar is the number of past mood episodes. 

CHRIS AIKEN: The time courses here may differ, with an early onset in ADHD and a later onset of cognitive problems in bipolar disorder. But, the cognitive symptoms themselves have a lot in common. There are very few differences, though, that might tip you off that they are due to bipolar. Unlike ADHD, cognitive problems caused by bipolar are more marked by memory impairment and mental slowing. So, get that if your patient has a lot of memory problems and slowing down of their thoughts, that's more likely due to bipolar than ADHD. People with pure bipolar usually lack the restless, frenetic energy of all those hyper-distracted thoughts that you see in ADHD. 

KELLIE NEWSOME: Now that you know some of the ways these diagnoses get tangled up, here’s a 5-step guide to untangle them in practice. When an adult with bipolar disorder presents with ADHD-like symptoms, use the following steps to figure out the cause. 

1. Wait until their mood episodes have resolved for 4-6 months before assessing for ADHD. 

2. Assess for childhood onset of ADHD before age 12 to rule out cognitive deficits from the progression of bipolar disorder.  

3. Rule out other causes of cognitive problems like substance abuse, sleep deprivation, traumatic brain injury, and medical illnesses (e.g., sleep apnea, hypothyroidism, cerebrovascular disease, recent infection). 

4. Screen for affective temperaments with the TEMPS-A scale. 

5. Carefully assess for ADHD with the DSM-5 criteria, preferably using a structured interview. 

CHRIS AIKEN: A structured interview will help filter out some of the look-alike symptoms that confuse the picture. It sounds cumbersome, but it’s not. These instruments simply translate the DSM criteria, which you should be using anyway, into questions like Do you often have difficulty sustaining your attention in tasks? And how was that in your childhood? The DIVA-5 is a good option as a structured interview for ADHD; you can find it online at http://www.divacenter.eu. Another one that covers ADHD along with a wider array of psychiatric disorders is the MINI-7.0, which you can find at https://harmresearch.org. A structured interview for ADHS and for other mental illnesses is going to do a pretty good job of ruling out other causes of ADHD symptoms, but there is one problem that remains. What if your patient meets the full DSM-5 criteria for ADHD but they also has a prominent affective temperament, so you are not sure if the cognitive problem are due to their temperament and it is really a mood disorder or if they are due to ADHD and the temperament is just a secondary thing? This is where things get difficult. Nassir Ghaemi has written a lot about this overlap, and to sum up his position, he views temperament, affective temperament, as primary, and he thinks that most of these cases in adults are due to the effective temperament and not to ADHD. I am not going to pretend to have an Occam’s razor here to slit the two apart.  So, I think in these cases, it's best to just acknowledge the uncertainty and proceed gingerly with treatment, starting with medications for ADHD that have a low risk of causing mania, those would be like clonidine or guanfacine, and we are going to get more into that in our next episode, where we talk about how to treat ADHD in bipolar patients. 

KELLIE NEWSOME: Let’s recap this episode: cognitive symptoms are common in bipolar disorder, even after the mood episodes have resolved. Common causes include cognitive deficits from the progression of mood episodes, affective temperament like cyclothymic or hyperthymic, or a genuine comorbidity with ADHD. A detailed history and some structured testing can clarify the cause. Now you know how to diagnose ADHD in bipolar. Next week, we’ll teach you how to treat it. Meanwhile, check out our new issue on our website for articles on tapering psych meds, antipsychotics in depression, and updates on Vyvanse, lithium, treatment-resistant depression, and schizophrenia. Get $30 off your first year’s subscription with the promo code PODCAST. Thank you for helping us stay free of commercial support.