Mapping long-term mental health in autistic kids

Previous research has shown that autistic children often experience mental health concerns. Studies investigating mental health in autistic people, however, often use mixed-age samples and analyse single time-points, leaving us with a bit of a blind-spot: how might the trajectory of autistic children's mental health shift and develop as they age? 

This is the question that inspired recent work by Dr Nicola Wright of Manchester Metropolitan University and colleagues. In their latest paper, they investigate both the types and timings of mental health problems in autistic and allistic (non-autistic) children, illustrating the mental health trajectories of these groups, as well as the varying trajectories experienced by those of different genders and classes.

For this research, data on autistic children were gathered from a longitudinal study of Canadian children. All were recruited to the study at the point of diagnosis, aged between two and four years old. Data on allistic children were taken from a different location — a cohort study on conduct issues in children based in the North West of England. In this second study, 1,233 mothers had been recruited during pregnancy and subsequently interviewed when their children were 2.5, 3.5, 5, 7, and 9.5 years old. 

Despite the potential differences between these two populations, these two studies employed the same measure: a Child Behaviour Checklist, which is used to assess behavioural, emotional, and attention problems in young people. Parents in both studies responded to a number of questions related to their child's behaviour, indicating how much they agree with statements probing whether their child feels the need to be perfect, for example, acts impulsively, or engages in risk-taking behaviour. Different versions of the checklist exist for different age groups, to reflect differences in behaviour as children age.

Once answered, the checklist is then converted into 'syndrome scales', measuring the presence or absence of various mental health issues. The current study focused on scores for the anxious/depressed scale, aggressive behaviour, and attention problems. Information on family income, maternal education, as well as the children's IQ were also collected. Finally, children took part in a semi-structured assessment designed to assess autistic symptoms in the domains of socialisation, affect, repetitive and restrictive behaviours, and overall severity. 

Overall, the researchers observed consistently higher levels of mental health issues in autistic children than allistic children, with small differences in overall growth patterns. Autistic children were more likely to exhibit 'anxious-depressed' problems compared to their allistic peers, and were more likely to demonstrate attention problems later in childhood. As the team notes, "demands on executive functions and social adaptation skills increase" during adolescence, which may also increase anxiety and depression – it may be that the more pressure autistic young people are under to meet to neurotypical norms and expectations, the more likely they may be to experience poor mental health. 

Autistic boys and girls, broadly speaking, had differing mental health trajectories. Autistic teenage girls were identified as more likely to be anxious or depressed than their male counterparts, and the team found lower rates of reported aggression and attention issues in girls. However, when girls were reported to experience these issues, they tended to manifest more suddenly than for boys. 

While this is interesting, this particular finding may be skewed by societal factors far larger than just this study. As the team highlights, girls often obtain their autism diagnoses later in life than boys. It would make sense, therefore, that those with more severe and obvious symptoms earlier in life are more likely to receive a diagnosis in childhood. Given that the current study's sample involved officially diagnosed children, it's likely that at least some of these sex differences are the result of wider diagnostic quirks. 

These sex differences were also significantly reduced when accounting for IQ. Both autistic and allistic children with higher IQs were less likely to exhibit symptoms of mental health issues (although, considering that symptoms were reported by parents rather than by children themselves, these results should be taken with caution). Higher IQ was also associated with a lower level of attention issues in autistic children, as well as with decreasing mental health concerns across childhood. 

External factors also played a role in shaping mental health trajectories of both autistic and allistic children, with factors such as lower family income being associated with higher scores on the anxious-depressed, aggressive behaviour, and attention problems scales. Those from higher income backgrounds, however, did not entirely escape these associations, as this income bracket was also associated with increases in anxiety and depression over time. 

Despite mapping the course of children's mental health in a new and informative way, this study does not come without its limitations. Perhaps most pressingly, the two studies compared in this paper were conducted in different countries, meaning there are potentially cultural factors that may have influenced the results. The racial and socio-economic make-up of the two studies is also different; the UK study in particular has lower racial diversity than the Canadian sample.

Knowledge of the child's diagnosis may have also impacted the results; parents may have picked up on and reported certain behaviours precisely because they were aware of similar behaviours associated with autism. The same behaviours in non-diagnosed children may have been missed, or seen as typical child behaviour, potentially widening gaps between group results. 

Read the paper in full: https://doi.org/10.1017/s0033291723001599