• Psychoactive drug use can cause physical, psychological and social harm.

• Drug-related harm depends on factors related to the drug and factors related to the person taking the drug.

• Drug-related factors include the type of drug, how it is used, the amount taken and the length of use.

• Person-related factors include genetic make-up as well as mental, physical and social health.

• Drug use can be broadly classified as recreational use, harmful use or dependence.

• For some people, the risk of drug dependence results from faulty brain functioning.

• Understanding patterns of harm helps clinicians decide if treatment is needed and, if so, which treatment is most likely to help.

• Some behaviour, such as gambling, can cause brain changes similar to those seen in drug dependence.

Measurable residual disease (MRD) is an established prognostic factor after induction chemotherapy in acute myeloid leukaemia patients. Over the past decades, molecular and flow cytometry-based assays have been optimized to provide highly specific and sensitive MRD assessment that is clinically validated. Flow cytometry is an accessible technique available in most clinical diagnostic laboratories worldwide and has the advantage of being applicable in approximately 90% of patients. Here, the essential aspects of flow cytometry-based MRD assessment are discussed, focusing on the identification of leukaemic cells using leukaemia associated immunophenotypes. Analysis, detection limits of the assay, reporting of results and current clinical applications are also reviewed. Additionally, limitations of the assay will be discussed, including the future perspective of flow cytometry-based MRD assessment.

The treatment of tremor is challenging, and therapeutic options are often limited and non-specific. Treatment always has to be individualized, and apart from the objective severity of tremor, significant importance should be given to subjective severity and impact of the tremor on the patient. Supportive non-pharmacologic and non-surgical methods should be incorporated into the treatment regimen. Finally, surgical therapy is proven and effective in several tremor syndromes and should be offered to eligible patients.

Autism spectrum disorder (ASD) is defined by the American Psychiatric Association as persistent deficits in social communication and interactions and restricted, repetitive patterns of behavior, interests, or activities. There are many potential etiological causes for ASD. In the United States, the combined prevalence of ASD per 1,000 children was 23 in 2018. The American Academy of Pediatrics (AAP) recommends screening specifically for ASD during regular doctor visits at 18 and 24 months to ensure systematic monitoring for early signs of ASD. Most reported concerns from parents relate to abnormal childhood developmental trajectory and history of unusual behaviors, with variability in ages when features suggestive of ASD are most noticeable. Behavioral interventions for ASD focus on minimizing the effects of developmental delays and maximizing speech/language, motor, social-emotional, and cognitive skills. Medications can be used to target comorbid conditions or problematic behaviors that interfere with progress or pose safety concerns. The financial burden on families of children with ASD is correlated with the existing societal financial safety net. Poorer outcomes are expected when the family carries a substantial share of the cost to support the development of children with ASD, especially in lower-income households.

Child and adolescent psychiatry (CAP) is a complex and challenging subspecialty in psychiatry that developed immensely in the last century. In this chapter, we present a brief overview of development and specific aspects of the assessment, diagnosis, and treatment of children and adolescents.

Psychiatric disorders are complex and multifaceted conditions that profoundly impact various aspects of an individual’s life. Although the neurobiology of these disorders is not fully understood, extensive research suggests intricate interactions between genetic factors, changes in brain structure, disruptions in neurotransmitter pathways, as well as environmental influence.

In the case of psychotic disorders, such as schizophrenia, strong genetic components have been identified as a key feature in the development of psychosis. Moreover, alterations in dopamine function and structural brain changes that result in volume loss seem to be pervasive in people affected by these disorders. Meanwhile, mood disorders, including major depressive disorder and bipolar disorder, are characterized by disruptions in neurotransmitter systems responsible for mood regulation, such as serotonin, norepinephrine, and dopamine. Anxiety and personality disorders also exhibit neurotransmitter dysfunction and neuroanatomical changes, in addition to showing a genetic overlap with mood and psychotic disorders.

Understanding the underlying mechanisms in the pathophysiology of these conditions is of paramount importance and involves integrating findings from various research areas, including at the molecular and cellular levels. This brief overview aims to highlight some of the important developments in our current understanding of psychiatric disorders. Future research should aim to incorporate a comprehensive approach to further unravel the complexity of these disorders and pave the way for targeted therapeutic strategies and effective treatments to improve the lives of individuals afflicted by them.

Bipolar disorder (BD) is one of the most important and potentially incapacitating mental disorders, typically characterized by the alternation of depressive symptoms with periods of elevated mood, called manic or hypomanic episodes. The present chapter provides an overview of the main aspect of this psychiatric condition, including its clinical presentation, diagnosis, pathophysiology, and therapeutic aspects. While the diagnosis and management of BD can be challenging, ongoing research has led to considerable advances in its understanding. It is expected that those advances will bring about improvements in the identification and treatment of this mental illness.

Personality disorders play a major role in psychiatric clinical practice. Usually evident by adolescence, they arise when emotions, thoughts, impulsivity, and especially interpersonal behavior deviate markedly from the expectations of the individual’s culture. These disorders comprise a group of diverse and complex conditions that still warrant better understanding across multiple dimensions: genetic, neurobiological, pharmacological, and psychodynamic. This chapter addresses the definitions of both personality and personality disorder and outlines the two sets of diagnostic criteria: primary characteristics of personality disorder and the three main categories/clusters of personality disorder. It also discusses incidence of the specific disorders and relevant treatment modalities. Treatments plans should include psychotherapy, psychopharmacology, and psychoeducation, as well as treatment of comorbidities and crises. Psychotherapy has been the intervention of choice for most personality disorders, with pharmacological treatment usually auxiliary and focused on symptoms. Clinician skill is a key element of diagnosis and treatment. An experienced clinician should be able to differentiate between personality traits or styles and actual personality disorders, a particularly challenging task when a patient presents in crisis. Individuals with personality disorders can manifest a disturbed pattern in interpersonal relationships that can be deleterious in the therapeutic relationship if not approached with skill.

A 20-year-old previously healthy man suddenly noticed that he was unable to run. The next day he could not climb the stairs and lost strength in his arms. He was admitted to hospital, and over the next hours he progressively lost muscle power in his arms and legs. Swallowing was progressively impaired, and he noticed minor tingling in both hands and feet. He had had a minor upper respiratory tract infection a week prior to admission.

A previously healthy, very active 68-year-old man, who usually cycled over 100 km several times a week, noticed progressive tingling in his feet and lower legs that increased over several weeks. This was followed by progressive weakness in the arms and legs exceeding a period of eight weeks. After three months of progression, weakness became so severe that he could not even walk without help. He did not use drugs or drink alcohol.

A 50-year-old man was initially seen by a rheumatologist because he had crooked fingers on the left hand and painful cramps. No rheumatological abnormalities were found. In the next three years, he developed severe atrophy and weakness of the left hand, and could not hold a glass of water. There were no sensory complaints. His GP considered motor neuron disease.

An introduction and overview of the mental health conditions relevant to people with intellectual disability. The chapter focuses on the evidence base to support or refute whether they suffer greater rates of mental health problems, Psychiatric classification and prescribing; Comparison tables of international classification of diseases (ICD) versions 10 and 11; and the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM) 4 and 5 and DC-LD.