It is by no means clear what special combination of endogenous and exogenous factors determines the occurrence of psychotic illness rather than of those milder and much more common disorders that are located on the borderline between mental health and mental illness. To the latter group belong psychogenic maladjustment and the pathological development of personality, although a diagnosis of psychopathy should be made with caution at a time when the personality is still in process of formation. Psychogenic maladjustment is facilitated by the psychological changes during puberty, although, because of the emotional instability, intensified self-awareness, and suggestibility that accompany it, it may be argued that the pubertal phase of psychological maturation is inevitably marked by transient maladjustments and behavioural difficulties. Since the group they constitute is clinically so indistinct, the bulk of mental disorders associated with puberty occupy a position intermediate between what is psychologically 'normal' and what is pathological, and may include both masked psychopathic and neurotic conditions, as well as examples of the initial manifestations of a psychosis.
Essential differences have been established between the clinical aspects of schizophrenia in adolescents in whom physical maturation is early and those in whom it is delayed. Unsynchronized development or disturbances of sexual maturation appear to be significantly associated with neurotic states or with pathological personality formation and psychopathic behaviour.
The importance of 'minimal brain damage' as a factor contributing to maladjustment has tended to be overlooked, though it may give rise to various psychopathological syndromes, especially under adverse environmental conditions. The primary symptoms of cerebral disorder such as hyperkinesia, clumsiness, defects of visuomotor performance, impulsive behaviour, or distractibility, may serve to frustrate or irritate the parents, causing them to react with anxiety or rejection towards the child. The child's own feelings of security are therefore impaired, with further delay and disturbance of psychological maturation.
The resulting clinical picture may therefore be complicated by the continuous interaction of neurological abnormalities and environmental factors. Disabilities which may have their basis in the minimal organic lesion, such as impulsivity, short attention span, or dyslexia, may lead to problems at school as well as at home. There are cases in which minimal brain damage in itself seems to be the main factor underlying delinquent behaviour, though more often there are associated factors such as hereditary loading, early childhood deprivation, or disturbed family relations. The manifestations of mental disorders in adolescence very often follow a common pattern of antisocial, psychopathic-like behaviour, which makes for difficulty both in classification and in a systematic approach to prevention and treatment.
It takes 8 months to recognize depression in a child, and the average recovery time is 9 months, although it can last 3 to 5 years and there is a 60% chance of a relapse. About one quarter of deeply depressed children are helped by medication.