Chapter 1 describes the defining characteristics of motivation ( i.e. purpose, flexibility and goal direction, reinforcement, affect, a capacity to overcome obstacles, resolution of competition), with varying sensitivity to internal (e.g. nutrient levels) and external incentive (e.g. food) factors. The dichotomy between approach and avoidance is introduced. It goes on to introduce the topics of the remaining chapters of the book. Motivation potentiates certain functionally appropriate responses (e.g. lordosis in the female rat). The chapter describes Tinbergen’s four types of explanation: causal, functional, evolutionary, and developmental/learning.

There are a wide range of sexual desires and intensities. What kind of motivational system could generate this? Appetitive and consummatory behaviour are distinct. There are on-line and off-line contributions. Hormones sensitize sexual motivation. There are organizational and activational phases of hormone action. People offer 237 reasons why they have sex. Wanting and liking are distinct. Sexual desire and sexual arousal are distinct but interactive. Excitation transfer is discussed. There are three levels of inhibition. The chapter discusses different brain regions and neurochemicals. The chapter describes ‘sexual priors’, the Coolidge Effect and the relevance of ‘life-history theory’. Sexual fantasy is rooted in part in incentive motivation. The complexities of sexual orientation are discussed, in terms of the incentive motivation model. Sexual desire often does not exist in isolation. Rather, it can interact with attachment, anger/aggression, and certain drugs (i.e. stimulants). The chapter then considers a number of paraphilias.

The foundation of the chapter is the distinction between regulation and control, and the link between them. The distinction is exemplified by the regulation of body temperature by means of control actions;for example, shivering, sweating, and changing the relation with the environment. The latter reflects motivation. The discussion then goes on to document a number of phenomena that also illustrate regulation and control: non-suicidal self-injury, hair pulling, skin picking, addictions of various sorts, and borderline personality disorder.

1. Causes of constipation in patients with cancer are multifaceted, but opioid induced constipation is the most common cause.

2. Constipation in cancer patients can lead to serious complications, including fecal impaction, bowel obstruction, and decreased absorption of oral medications, which can impact the effectiveness of cancer treatment.

3. Bulking agents can be used in mild cases of constipation but should be avoided in patients with severe disease, taking anticholinergic drugs or opioids, and those with poor oral intake.

4. Stool softeners can be helpful in patients with anal fissures or hemorrhoids to allow for less painful bowel movements. Polyethylene glycol is recommended as first line due to its low cost, rapid onset, and rare adverse side effects.

5. Peripherally acting mu-opioid receptor antagonists (PAMORA) bind only to opioid receptors in the gut, counteracting constipation side effects without decreasing analgesic effects.

Chapter 28 covers the topic of opioid use disorder. Through a case vignette with topical MCQs for consolidation of learning, readers go through the management of a patient with opioid use disorder from from first presentation to subsequent complications of the condition and its treatment. Topics covered include symptoms and diagnosis of acute intoxication and withdrawal symptoms of opioids and management including that of use in pregnant women.

Poisoned patients who present to the emergency department often require a period of observation to determine their ultimate disposition. Most poisoned patients are able to be discharged within 24 hours, which makes them good candidates for observation unit (OU) admission. Data suggests that clinicians using well-defined protocols can safely manage poisoned patients in the OU. Benefits of OU care for this patient population include earlier involvement of multidisciplinary teams, shorter length of stay, conservation of resources and potential cost-savings. Pediatric poisoned patients in particular are excellent candidates for OU protocols. Multiple agents have been managed in the OU, such as acetaminophen, benzodiazepine, carbon monoxide, stimulants, opioids and various envenomations. OU protocols are not limited to single agent ingestions. OUs may also be used for buprenorphine initiation for the opioid addicted patient. The most effective protocols utilize the expertise of medical toxicologists to help risk stratify appropriate patients for OU care. With well-designed protocols, the poisoned patient can be effectively and safely managed in the ED OU.

Chronic pain can be categorised as nociceptive, neuropathic or nociplastic based on the underlying pathophysiology. It is considered a disease in its own right and can be sub-classified to differentiate types of chronic pain syndromes. Chronic primary pain is defined as pain in one or more anatomical regions, persisting or recurring for more than 3 months, and associated with significant emotional distress or interference with activities of daily life e.g. fibromyalgia or complex regional pain syndrome. Chronic secondary pain includes six subgroups where pain has initially developed as a symptom of another disorder or disease process e.g. chronic cancer-related pain and chronic neuropathic pain.

The experience of pain is a consequence of a variety of biological, psychological, and social factors and a wide range of pharmacological and non-pharmacological interventions are available. Pharmacological management involves opioid agents and non-opioid medications including simple analgesics, topical lidocaine, and capsaicin, anti-epilepsy drugs and antidepressants. Tolerance to opioids can develop rapidly. Misuse and abuse are increasing concerns. Non-pharmacological interventions include psychological and physical therapies. Patient engagement in the process is key and an interdisciplinary approach is recommended which focusses on the individual patient and uses a shared-decision model.

Over the past two decades, the emergency department (ED) has seen an increase in opioid use-related admissions. The ED serves at the frontline of addressing the morbidity and mortality associated with opioid use disorder (OUD). Therefore, it has become a growing consensus that the ED should implement strategies that address OUD and optimize patient outcomes. As such, the observation unit (OU) in the ED has been shown to be an effective site for the observation and management of opioid withdrawal, as well as initiate medication-assisted therapy (MAT). Patients are offered up to 72 hours of MAT doses but are connected to outpatient facilities for long-term management. This initiation in the ED is shown to be more effective in the long-term management of OUD versus referral only. As we continue to manage OUD in the ED, more studies are necessary to establish a standard dosage for buprenorphine therapy, and standardize and solidify MAT initiation in the ED.

Substance use disorders are a major risk factor for maternal mortality, and opioid overdose is a leading cause of maternal mortality in several states. Pregnant and postpartum patients should be assessed for substance use disorders using a validated screening tool, and if present, should be managed with counseling, initiation of pharmacotherapy, and referral for ongoing treatment. Acute presentations of opioid intoxication and opioid withdrawal should be identified and treated. The recommended treatment of opioid use disorder in pregnancy is pharmacotherapy using an opioid agonist. Either buprenorphine or methadone may be appropriate, depending on patient preferences and available treatment resources. Patients should receive education on recognition and prevention of opioid overdose and a prescription for naloxone for overdose reversal.

Stimulants like cocaine, amphetamines, and ecstasy produce short-term desirable effects like alertness, euphoria, and energy. However, they can also cause short- and long-term harm, leading to addiction, dependence, and withdrawal syndrome. Sedative drugs like cannabis, opioids, and benzodiazepines create feelings of calmness and relaxation but can be dangerous in overdose, particularly if mixed with other sedatives. Repeated use of sedatives can lead to severe dependence. Cannabis is the most commonly used illegal drug and can cause paranoia, psychosis, memory problems, and mood disorders with long-term heavy use. Synthetic cannabinoids like ‘spice’ are stronger and more harmful than natural cannabis. Hallucinogens like LSD cause distortions, hallucinations, confusion, and disorientation. They don’t cause dependence but can damage the brain with repeated use. Dissociative drugs like nitrous oxide and ketamine cause disorientation, perceptual disturbances, and loss of physical coordination, leading to accidental injury. Long-term use of ketamine can damage the bladder, and nitrous oxide can cause memory problems and severe nerve damage.

The fact that opioids constrict the pupil is known to healthcare workers and the lay public. In this chapter, the mechanism of this effect is discussed and how an understanding of this mechanism can be useful to the clinician. There are many parameters that can be measured from the pupil with portable pupillometers. The measure that most closely predicts the onset of severe respiratory depression is pupillary unrest in ambient light (PUAL). This measure is compared to pupil size and pupillary constriction amplitude as a measure of toxic levels of opioids.

Trained in addictions in Edinburgh, perhaps an easier specialty given personal experience. Then obtained a consultant post in the Scottish Borders, and a year later one in Edinburgh.