When treatments for high-prevalence mental disorders don’t work as usual

• Some patients with highprevalence mental disorders do not improve with medical and psychological interventions that work in other patients.
• In such patients, assessment for neurodevelopmental concerns should be made, as neurodevelopmental disorders and HPMDs frequently coexist.
• Patients with both an HPMD and a neurodevelopmental disorder benefit from annual secondary or tertiary review; skilled resources are difficult to find, but shared care can work well.

It seems fair to consider reconceptualising neurodevelopmental disorders to a more acceptable term, such as neurodiversity

Recently, I was asked to see Bobby, a 40-year-old New Zealand European. Bobby has experienced mental health problems most of her life, including chronic low mood with frequent relapses into depression, significant anxiety, low motivation and difficulty initiating sleep. In her past, she had engaged in self-harm and been referred to a local dialectical behaviour therapy programme.

When I saw her, she was developing a significant alcohol problem, which helped her relax, manage her anxiety and initiate sleep. She struggled with ongoing chronic low mood, generalised anxiety and a lack of fulfilment as she thought she had not lived up to her potential. This dissatisfaction was striking, despite Bobby being very successful in some aspects of her life.

As a 15-year-old, she was in a New Zealand women’s team in a major sport. After secondary school, she attended a small college in the US on an athletics scholarship, after turning down a scholarship at a major Division I college. She is now a talented musician interested in mixing and producing records for other New Zealand artists.

Bobby had turned down the Division I scholarship because she was concerned about the academic requirements. Throughout her schooling, she struggled to interpret written passages and express herself in writing, and grappled with anything more than basic addition and subtraction. She carried the shame of this all her life, believing she simply wasn’t very intelligent.

However, her spoken communication indicated otherwise – she exhibited a wide lexicon, expressed herself well, and appeared intelligent and perceptive. She had progressed through school, partly due to her sporting success, and partly because she was quick-witted enough to cover her learning shortcomings.

While on scholarship, she experienced significant emotional problems relating to her inability to manage her social environment, resulting in an admission to a psychiatric unit. Upon return to New Zealand, she saw several psychiatrists in public and private practice, who tried, with mixed success, to manage her depression and anxiety. She continued to have to handle her social situation carefully, finding a recent sixweek music tour emotionally taxing because she was in constant close contact with others.

My opinion was that Bobby had attention-deficit/hyperactivity disorder (ADHD), on the basis that she appeared neurodevelopmentally abnormal, with strengths such as her prodigious sporting and musical talent, and clear weaknesses with everyday skills that most of us take for granted.

The contrast between her verbal and written communication was striking, and it was clear she had dyslexia and dyscalculia. She found it difficult organising herself to undertake complex tasks, often procrastinating and delaying the tasks she knew were going to present challenges.

She described her anxiety as being related to her “overthinking”, and her mood problems appeared consistent with chronic dysthymia combined with mood lability and frustration tolerance difficulties. She reported that her thoughts were fast and bounced between topics, despite attempts to keep them focused.

A stimulant trial combined with sleep support with melatonin was immediately successful. Bobby reported less anxiety and overthinking, improved motivation and a much more organised working environment. She has started to pursue musical projects as she is better able to manage her anxious thoughts. We are working on her medication regimen, and, once stable, her GP can prescribe and monitor this.

Bobby’s case is an example of a complex psychiatric problem with significant consequences for daily function. She exists within an under-recognised group of people who have both a neurodevelopmental disorder and a high-prevalence mental disorder (HPMD).

Common neurodevelopmental disorders include ADHD, autism spectrum disorder (ASD), learning disorders and intellectual disabilities. Common HPMDs include depression, anxiety and post-traumaticstress disorder.

Primary care practitioners are often very effective in treating HPMDs with medication and access to psychotherapy, but neurodevelopmental disorders and HPMDs frequently coexist. When they do, resolution of the HPMD is less common, and relapse is frequent.

It makes sense to think carefully about the term “neurodevelopmental disorders”. Bobby’s case is one where she struggles with motivation and competencies around written communication, but has talent and drive that led to sporting and musical success. She could be considered “disabled”, but, centuries ago, she would have been considered gifted.

It seems fair to consider reconceptualising neurodevelopmental disorders to a more acceptable term, such as neurodiversity. Neurodiversity refers to variation in human brain functioning around sociability, learning, attention, mood, sensation and sleep.

Such variability exists in a significant proportion of the population in the same way that anatomical variance contributes to the evolution of a species. However, in modern society, complex cognitive tasks, written communication, screening out unwanted stimuli, and mood management are all important skills.

Using the term neurodiversity acknowledges that this variance is not always pathological. It also acknowledges that the diagnostic categories of ADHD, ASD, learning disorders and intellectual disabilities have significant overlap, with neurodiverse people exhibiting features of each of these.

It is common in clinical practice, as in Bobby’s case, to see features of coexisting learning disorders (dyslexia, dyscalculia), ADHD (inattention, mood lability and impaired frustration tolerance) and ASD (becoming socially overstimulated).

Neurodiversity is associated with an increased rate of HPMDs across the lifespan. Childhood and adolescent depression occurs 14 times more often in those with ADHD. Adults with ADHD progress to a diagnosis of depression at five times the rate than those without, and anxiety at four times the rate. A study looking at primary care databases in Scotland noted those with intellectual disabilities had 2.6 times the rate of anxiety than those without. These difficulties can often be difficult to treat, take longer to resolve, and are more likely to recur.

Neurodiversity is also associated with increased rates of serious mental illness. Those diagnosed with ADHD are diagnosed with bipolar affective disorder at approximately five times the rate of the general population. The presence of any neurodevelopmental disorder will result in three to five times the rate of adult schizophrenia, and 30 per cent of those with ASD experience hallucinations. A major meta-analysis found 6 per cent of people with ASD and normal IQ scores also met the criteria for schizophrenia. The Scottish primary care study found schizophrenia is seven times more common in those diagnosed with intellectual disabilities than the general population.

Those reading this far may have noticed that all studies mentioned look at a population of the neurodiverse, then screen for increased rates of HPMDs and serious mental illnesses. Most studies looking at comorbidity between neurodiversity and mental illness are orientated in this direction. Few studies look retrospectively from the diagnosis of mental illness to investigate rates of neurodiversity.

In my practice as a youth forensic clinician, I ask questions about neurodevelopment when assessing all patients, regardless of categories for diagnostic enquiry. One key principle of assessing childhood neurodevelopment is that adults looking retrospectively find it difficult to compare themselves with their peers prior to the age of 12.

This means collateral history from parents and whānau is vital, and the clinician needs an awareness of how neurodiversity expresses itself differently between childhood and adolescence.

For example, ADHD diagnostic criteria are based on observations of children aged six to nine, but because recall of childhood comparisons is poor, asking the classic questions about hyperactivity, impulsivity and inattention in primary school will not yield accurate answers.

Assessing ADHD retrospectively requires concentration on questions about adolescence. Questions about inner restlessness, mood lability (sudden changes in mood), poor frustration tolerance, and difficulties completing complex cognitive tasks are recommended. These represent the developmentally appropriate areas for hyperactivity, impulsivity and inattention symptoms, respectively.

Learning disorders can be assessed by asking about the subjects that were extraordinarily difficult at school, compared with the subjects that were easy. This offers valuable clues around learning strengths and weaknesses.

ASD can be observed in interviews by looking for overly formal, stifled and rigid interactions with limited eye contact. Additional questions relating to cognitive flexibility and adaptability can help.

I am not suggesting primary care practitioners are resourced to undertake complex psychiatric interviews. However, if a patient with an HPMD is not improving after multiple different therapeutic approaches, considering comorbid neurodiversity can be helpful. A referral to secondary mental health services or private psychiatrists documenting treatment resistance and suggesting a comorbid neurodevelopmental disorder can help significantly.

Due to resource constraints and constant understaffing, mental health services are forced to adopt a model of care that prioritises short and medium-term treatment. Once the patient recovers, they are discharged to primary care. Some teams (eg, intensive community teams) are dedicated to close work with individuals who are chronically mentally ill, but most services are forced to discharge patients after intense, short periods of care.

Because people with neurodevelopmental abnormalities have a lifelong disorder that will express itself differently at different developmental stages, any model focusing on intensive, short-term intervention will not work.

The ideal model for neurodevelopmental disorders involves a long-term engagement with intermittent review periods, and close liaison with primary care. A patient with ADHD, ASD or intellectual disabilities needs yearly appointments, rather than treatment then discharge.

James Gardiner is a forensic psychiatrist with the Regional Youth Forensic Service, Auckland DHB

Details have been changed to protect patient confidentiality

You can use the Capture button below to record your time spent reading and your answers to the following learning reflection questions:

• Why did you choose this activity (how does it relate to your PDP learning goals)?
• What did you learn?
• How will you implement the new learning into your daily practice?
• Does this learning lead to any further activities that you could undertake (audit activities, peer discussions, etc)?