PSYCH 019: Gene Mapping Investigations of Psychiatric Disorders

PSYCH 019: Gene Mapping Investigations of Psychiatric Disorders

If multi-omics reveals layers of biological complexity, gene mapping attempts to locate patterns within that complexity. This chapter explores how researchers identify genetic contributions to psychiatric disorders - not through single genes, but through probabilistic associations across the genome. In this episode, we examine approaches such as linkage studies, candidate gene studies, and genome-wide association studies (GWAS). These methods do not identify deterministic causes, but patterns of increased risk distributed across many genetic loci. We explore the concept of polygenicity - the idea that psychiatric disorders arise from the cumulative effect of many small genetic variations rather than a single mutation. This reframes conditions such as schizophrenia, depression, and bipolar disorder as complex traits rather than discrete genetic diseases. We also examine the challenges: small effect sizes, overlapping genetic risk across disorders, and the difficulty of translating statistical associations into biological mechanisms or clinical practice. Gene mapping does not provide simple answers. Instead, it offers a map of probabilities - a way of understanding vulnerability as distributed, shared, and context-dependent. This chapter invites a shift from certainty to pattern recognition - where risk is not located in a single place, but emerges from the architecture of the genome as a whole. Key Takeaways * Gene mapping identifies associations between genetic variants and psychiatric disorders. * Methods include linkage studies, candidate gene approaches, and GWAS. * Psychiatric disorders are highly polygenic, involving many variants with small effects. * Genetic risk is probabilistic, not deterministic. * There is significant overlap in genetic risk across different psychiatric conditions. * Translating genetic findings into clinical practice remains challenging. * Understanding risk requires thinking in patterns rather than single causes. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 018: Genome, Transcriptome, and Proteome: The Molecular Genetics, Biochemistry, and Multi-Omics Underlying the Neurobiology of Mental Disorders

If genes are the script, they are only the beginning of the story. This chapter expands the lens to multiple layers of biological information - genome, transcriptome, and proteome - revealing how psychiatric disorders emerge not from single mutations, but from complex systems of regulation and interaction. In this episode, we explore how the genome provides the foundational code, while the transcriptome reflects which genes are actively expressed, and the proteome represents the functional molecules that carry out biological processes. Together, these layers form a dynamic, multi-level system - often referred to as “multi-omics”. We examine how these systems interact across time and context, influenced by development, environment, and experience. The same genetic code can lead to different outcomes depending on how it is expressed and regulated. This framework moves psychiatry beyond simple genetic determinism. Mental disorders are not the result of isolated gene defects, but of complex networks involving gene expression, protein function, and environmental interaction. The chapter also introduces the potential of multi-omics approaches in advancing diagnosis, prediction, and personalised treatment - while highlighting the current limitations and complexity of translating these findings into clinical practice. Ultimately, this is a chapter about depth - revealing that beneath observable symptoms lies a layered biological system, intricate and still only partially understood. Key Takeaways * The genome provides genetic code, but expression occurs through transcriptome and proteome layers. * Multi-omics integrates these levels to understand biological function. * Gene expression is dynamic and influenced by environment and development. * Psychiatric disorders arise from complex interactions, not single gene defects. * Biological processes operate across multiple interconnected layers. * Multi-omics offers potential for personalised psychiatry but remains complex. * Understanding these systems shifts thinking from static genetics to dynamic regulation. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 017: Basic Science of Appetite

Appetite is often mistaken for a simple biological drive, but it is in fact a finely regulated system integrating energy balance, reward, emotion, and cognition. This chapter explores how the brain determines when to eat, what to eat, and when to stop. In this episode, we examine the interplay between homeostatic systems - which monitor energy needs - and hedonic systems, which assign pleasure and reward to food. The hypothalamus plays a central role in maintaining balance, responding to hormonal signals such as leptin and ghrelin. At the same time, reward circuits involving dopamine shape motivation and craving. We explore how appetite is influenced by context, emotion, and environment. Eating is not simply about energy - it is embedded in social, psychological, and cultural frameworks. Dysregulation in these systems can lead to a range of psychiatric and behavioural conditions, from eating disorders to obesity and addiction-like patterns of consumption. These are not failures of willpower, but alterations in the systems that regulate need and reward. This chapter reframes appetite as a negotiation - between biological necessity and experiential desire - revealing how the brain balances survival with meaning. Key Takeaways * Appetite is regulated by both homeostatic and hedonic systems. * The hypothalamus monitors energy balance and responds to hormonal signals. * Hormones such as leptin and ghrelin influence hunger and satiety. * Reward systems, particularly dopamine pathways, shape food-related motivation. * Appetite is influenced by emotional, social, and environmental factors. * Dysregulation can contribute to eating disorders, obesity, and addictive behaviours. * Eating reflects both biological need and psychological meaning. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 016: Pain Systems: Interface with Affective and Motivational Mechanisms

Pain is often described as a sensory experience, but in psychiatry it is something far more complex. This chapter explores how pain is constructed at the intersection of sensory input, emotional processing, and motivational systems. In this episode, we examine how nociceptive signals are only the beginning. The brain interprets these signals through networks involving the insula, anterior cingulate cortex, limbic structures, and prefrontal regions - transforming raw input into subjective experience. Pain is therefore not just about intensity, but about meaning. The same stimulus can be experienced differently depending on context, expectation, mood, and prior experience. This explains why pain and emotion are so tightly linked, and why chronic pain often coexists with depression and anxiety. We explore how pain influences behaviour - driving avoidance, attention, and adaptive responses - and how these mechanisms can become maladaptive when pain persists or becomes centralised. This chapter reframes pain as a multidimensional experience: sensory, emotional, and motivational. It challenges the idea of pain as purely physical, revealing it instead as a deeply integrated brain–mind phenomenon. Key Takeaways * Pain is not purely sensory; it includes emotional and motivational dimensions. * Brain regions such as the insula and anterior cingulate cortex are central to pain processing. * Context, expectation, and prior experience shape the perception of pain. * Pain and emotion are closely linked at the level of neural circuits. * Chronic pain involves changes in central processing, not just peripheral input. * Pain influences behaviour, attention, and decision-making. * Understanding pain requires integrating biological, psychological, and social factors. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 015: Basic Science of Sleep

Sleep is often treated as absence - a passive state where the brain switches off. This chapter challenges that notion, revealing sleep as an active, highly organised process essential for brain function and mental health. In this episode, we explore the architecture of sleep - its stages, cycles, and regulatory systems. Non-REM and REM sleep represent distinct physiological states, each contributing differently to restoration, memory consolidation, and emotional processing. We examine how sleep is governed by two interacting systems: the circadian rhythm and the homeostatic drive. Together, they determine when we sleep, how deeply, and for how long. Disruptions to either system can destabilise the entire process. Sleep is not merely restorative - it is transformative. During sleep, the brain reorganises information, processes emotional experiences, and clears metabolic by-products. It is a period of recalibration, not inactivity. Clinically, disturbances in sleep are both symptoms and drivers of psychiatric disorders. Insomnia, hypersomnia, and altered sleep architecture are closely linked to mood disorders, anxiety, and psychosis. This chapter reframes sleep as foundational - not optional, but integral to how the brain maintains coherence and resilience. Key Takeaways * Sleep is an active, structured process essential for brain function. * Non-REM and REM sleep serve distinct roles in restoration and processing. * Sleep is regulated by circadian rhythms and homeostatic drive. * It supports memory consolidation, emotional regulation, and metabolic clearance. * Disruptions in sleep can both reflect and contribute to psychiatric disorders. * Sleep architecture (timing, depth, cycles) is clinically significant. * Rest is not passive - it is a critical component of neural health and function. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]