Introduction

One generation ago there were few psychiatrists and psychologists who approached mental disorders with a developmental perspective. Nowadays this is different. The development perspective is very popular and is therefore frequently used.

Causes of schizophrenia in childhood

Originally, schizophrenia is conceptualized as a psychosis that generally begins in adolescence or early adulthood. Children who later developed schizophrenia, however, already had social, emotional and behavioral problems in their childhood. For example, poor attention in children is a predictor of later schizophrenia. Epidemiological and longitudinal studies of the entire population have also shown that there are predictors of schizophrenia in early childhood, despite the fact that schizophrenia itself does not become public until adolescence or early adulthood. These predictors include a delay in motor development, difficulties in understanding language and cognitive functioning. These associations with schizophrenia are independent of socio-economic, obstetric and educational effects. Research has also shown that schizophrenia in adults is often preceded by social-emotional behavioral problems. However, this also applies to many other psychopathological disorders and therefore it is not possible to identify specific predictors of schizophrenia.

There are three problems that seek a solution when it comes to predicting schizophrenia from childhood and adolescence traits. First of all, a distinction is often made between predictors (risk factors) and prodromal (early manifestations of a disorder) factors. In general, this classification is also correct, but there is also a large proportion of people who already exhibit prodromal factors, but who do not continue to develop the disorder afterwards. Secondly, the question is what causes it that these risk factors or early manifestations sometimes lead to the occurrence of a disorder sometimes and sometimes not. Three possible answers for this are that brain development in adolescence is crucial, that excessive use of cannabis contributes to the development of the disorder (only if you already have risk factors or early manifestations of schizophrenia), and that certain types of social removal, such as relocation and insulation, make a major contribution.

Neuro-developmental disorders

Neuro-developmental disorders have eight main characteristics. The first is that they reveal themselves through a backlog or a deviation in psychological traits that are influenced by the growth process. Furthermore, the course of the disorder does not contain any periods in which things go better. In general, the disorder becomes a little less severe, the more mature a person becomes, but the disappearance, the disorder almost never does. Furthermore, the disorders all contain a specific or general cognitive impairment. There is also a lot of overlap between the various disorders. The genetic influence on these disorders is very large, but environmental influences also play a role. Finally, it is striking that especially men have this category of disorders.

Autism and related disorders

Sometimes characteristics of autism are already visible in the first year of life of a child, but usually characteristics are not really visible for 18 months and a diagnosis can usually only be made from 2 years. The best predictor for autism is the IQ and the use of language at the age of 5 years. Yet IQ is not a very good predictor, because many children with an IQ above 70 could develop an autistic disorder.

Specific language disorder

The name suggests that this disorder only causes language problems, but this is not entirely true. But one in six people with this disorder has a permanent paid job and one in six has never had a paid job. The majority do not live independently, more than half have problems with friendships and just over a quarter have ever had a long-term relationship. Even though the language problems persist into adulthood, the biggest problem is actually social functioning and social relationships.

Research into this disorder has revealed a number of striking things. Children who have problems with language development at an early age can often catch up with this backlog, but the problems often come back when these children go to school and then the problems persist well into adulthood. It also appeared that there is a certain overlap between autism and a specific language disorder. Genetic factors play an important role, especially in a somewhat worse form of the disorder. Furthermore, this disorder should not be referred to as a language disorder, but rather as a more general social / cognitive disorder.

Dyslexia

Dyslexia can only be diagnosed after a child has reached an age at which the child should normally be able to read. Yet dyslexia is largely genetic and there are also a number of characteristics (cognitive and linguistic) visible in the years before a child goes to school.

ADHD

ADHD is strongly influenced by genetic factors, is mainly found in men, is associated with many other cognitive defects and is thought to originate in problems with cognitive processing. The problems lie mainly in poor control of behavior, problems with the executive functions of inhibition and working memory and an aversion to slowness.

ADHD often occurs together with ODD and CD, probably because they have common underlying genes. In addition, children with ADHD have a greater chance of developing psychopathological disorders later. The prognosis for ADHD is poor, especially when someone shows hyperactivity at school or at school and at home. ADHD certainly has effects in adulthood, but these often no longer meet the diagnostic criteria that are set for ADHD in children.

Depression

If depression occurs in adolescence, the chance of more depression in adulthood is high. It is often assumed that this chance is greater for women, but this is probably not the case. If depression occurs before puberty, there is no great chance of developing depression later. Therefore, it is thought that depression that occurs in childhood differs significantly from depression that occurs in adolescence or adulthood. This idea is supported by the fact that children and adults respond very differently to antidepressants.

Heredity plays a greater role in depression that develops in adolescence or adulthood than in depression that develops in childhood. Probably this is because depression in adolescence is mainly triggered by negative experiences and the extent to which someone gets caught up in it is genetically determined.

Negative experiences can cause depression in different ways. Children and adults who are depressed behave in such a way that they increase the chance that they will end up in situations where they will experience stress, which will make the depression worse. Cognitive biases are also likely to play a major role in vulnerability to depression. Children can have a bias for negative statements and memories from the age of five.

Comorbidity

Anxiety often starts in childhood and is a predictor of major depression in adulthood. Probably the same genes underlie this, but the expression of these genes is different in different stages of life. Particularly a separation disorder, a general anxiety disorder and a panic disorder are good predictors for a later major depression. There are also various indications that a major depression in adolescence is precisely a predictor of anxiety in adulthood and especially of a general anxiety disorder.

The question remains whether anxiety and depression are two different disorders, whether they have the same underlying problem or whether they are in a causal relationship with each other. The conclusion that, in general, anxiety disorders are a risk factor in the development of depression can be drawn. This relationship is probably mediated by hormonal influences in puberty and an increased chance of negative experiences and cognitions.

Antisocial behavior

Most adults who exhibit antisocial behavior have a long history of behavioral problems. Yet it is not the case that all children with behavioral problems start to show antisocial behavior later in their adulthood.

Heterogeneity

Antisocial youth can be divided into two groups, which differ in when the behavior arose, when risk factors were already present and in how long the behavior remains present. The poor prognosis is for people who have problems early in childhood, who are male, who have neuro-development problems and who have a negative environment. Antisocial behavior that only emerges in adolescence has a better prognosis, since abnormal behavior is a little part of this phase and the behavior generally disappears when these young people start to take their responsibilities.

Not all people who show behavioral problems at an early age also show antisocial behavior in adulthood. A small group is developing a positive adaptation style, but it is not entirely clear why this is. There is also a group that exhibits behavioral problems early on, but where the later problems are of a completely different kind. These people show symptoms of social isolation, poor development of friendships and a vulnerability to anxiety and depression in adulthood. This group often shows an aversion to social situations and neuropsychological problems in childhood. It seems logical that it is simply a question of personal characteristics or that early negative experiences and problems lead to avoidance behavior or, conversely, to openly antisocial behavior.

It is also questionable whether the prognosis for people who show antisocial behavior until adolescence is really so much better than for an earlier start of this behavior. After all, these people show much more criminal behavior and substance abuse later on, and problems with mental health also often occur.

Persistence and removal mechanisms

Genetic factors play a major role in the origin and continuation of antisocial behavior, but there is certainly interaction with the environment. Genetic factors can cause people to react negatively to the person who is someone and can determine in which situations someone comes.

If such a person comes into contact with stable, positive relationships, the early process of behavioral problems can be turned around positively. The extent to which someone benefits from all kinds of positive circumstances also depends on the person himself. Change moments can be associated with moments when someone's past is really separated from the future, such as new opportunities for relationships, social networks, new options for controlling behavior, structural activities and a new identity formation.

Risks of psychiatric disorder in adulthood

Antisocial behavior in childhood and adulthood is strongly associated with later psychiatric disorders. Behavioral problems at the age of 11-15 increase the risk of all psychiatric disorders, both internal and external, at the age of 26. Many factors probably play a role in this, such as encouraged substance abuse by friends, poor family ties and a need for money for drugs and alcohol. Behavioral problems often have different dysfunctions, both in behavioral and emotional areas.

Substance abuse

The vast majority of young people do experiment with alcohol and drugs, but in general this does not result in substance abuse in adulthood. This result depends, among other things, on other disorders that people may have and especially behavioral problems correlate strongly with later substance abuse. ADHD also increases the chance of later substance abuse, but it is possible that this chance is also mediated by behavioral problems associated with ADHD. The link between depression and substance abuse is more complicated. Depressed people may use alcohol and drugs as a kind of self-medication, but a direct effect of depression on substance dependence has not yet been found. However, the prediction from substance abuse to a later depression is very strong. Substance abuse in adulthood is associated with both hereditary and psychosocial problems.

Umbrella themes

Concepts that are often used when looking at the psychopathology phenomenon are heterotypic continuity and psychopathological progress. These concepts suggest that there is meaningful continuity with the different disorders, but that the manifestations of these may differ at different stages of life. Examples include reading problems in children who predict spelling problems in adulthood, neurodevelopmental problems in young children, psychosis-like symptoms in later childhood and psychoses and schizophrenia in adolescence and adulthood, and early anxiety symptoms as predictors of later depression. However, it is still not entirely clear why anxiety symptoms are a predictor of later depression (most common) or depression of later anxiety disorders. With schizophrenia, the development is even more complicated. Language and motor deficits are predictors of schizophrenia, but there is little continuity in this.

The same applies to psychotic symptoms. The predictors of schizophrenia are therefore much more common than schizophrenia itself.

It is not entirely clear how the process from a specific language disorder to a general social disadvantage fits into this picture. It is not logical to see social problems as completely independent of the language disorder, so there are probably social problems before and these probably start with a delay in the use and understanding of language. The term heterotypic continuity is therefore probably also applicable here. The change from early behavioral problems to later substance abuse and from ADHD to a later antisocial personality disorder can probably be better reflected with the concept of psychopathological progress.

Early onset of symptoms

It is often assumed that an early onset of symptoms is a direct cause of the severity of psychopathology. Real structural research into this has not yet been done, so it is not yet possible to say anything with certainty about this statement. In general, psychopathology that has a long history of symptoms is more serious than psychopathology that does not.

Mediators of continuity and discontinuity

Genetic factors most likely play a mediating role in psychopathology. It also plays a role that the chance of a relapse increases if someone has already had an experience with a disorder. In addition, some disorders increase the chance of someone entering a risky environment and negative experiences in childhood or adulthood increase the chance of depression. Furthermore, the way an individual responds to a disorder influences the chance of a later relapse and the way people think about the disorder influences the course of the disorder.

Predictions

First of all, the question is whether later psychopathology includes abnormalities that may be present at an early age. Then it must be examined whether it is at all possible to measure these deviations reliably and validly. False negatives and false positives are very common in research into the early symptoms of psychopathology, so attention needs to be paid to that. A balance must therefore be found for the risk of many versus the benefits for a number of people.

Theoretical perspectives

Development largely involves continuity and change and both concepts contain coherence, laws and organization. There is an unchanging interaction between genes and environment and development in the early years continues to influence later development. There are many individual differences in the course and causes of a disorder and there is an extensive continuity between normality and psychopathology.

Directions for further investigation

Attention must be paid to the alternatives that compete with each other as mediators for psychopathology, and this requires many measurements, research designs and data analyzes. There is a particular need to find factors that are important in the changes in adolescence. Until now, genetic designs have not been used much and it is good to make more use of them in research into the interaction between environment and genes.