Psychiatry Flashcards

A 17-year-old female presents with restricted eating, intense fear of gaining weight, and a BMI of 15 kg/m². She perceives herself as overweight despite being underweight. What is the most likely diagnosis?

Answer: Anorexia nervosa

Anorexia nervosa is characterised by restriction of energy intake leading to significantly low body weight (BMI <18.5), intense fear of gaining weight, and disturbed body image. A BMI of 15 represents severe anorexia nervosa.

A patient on lithium presents with tremor, polyuria, and a serum lithium level of 2.5 mEq/L. What is the immediate management?

Answer: Stop lithium, IV fluids, and monitor renal function

Lithium toxicity (levels >1.5 mEq/L) requires immediate cessation of lithium, aggressive IV fluid hydration (normal saline), and monitoring of renal function and electrolytes. Haemodialysis may be needed for severe toxicity (>2.5 mEq/L) or renal impairment.

A 35-year-old woman experiences recurrent, unexpected panic attacks with palpitations, shortness of breath, chest pain, and fear of dying. She now avoids crowded places. What is the most accurate diagnosis?

Answer: Panic disorder with agoraphobia

Panic disorder is characterised by recurrent unexpected panic attacks with persistent concern about future attacks. When the patient develops avoidance of situations where escape might be difficult (crowded places), agoraphobia is diagnosed as a comorbid condition.

A veteran presents with flashbacks, nightmares, hypervigilance, and emotional numbing 3 months after a traumatic combat experience. He avoids anything related to the event. What is the diagnosis?

Answer: Post-traumatic stress disorder (PTSD)

PTSD is diagnosed when symptoms (intrusion/re-experiencing, avoidance, negative alterations in cognition/mood, hyperarousal) persist for >1 month after a traumatic event and cause significant distress. Acute stress disorder is diagnosed within the first month.

A 70-year-old man presents with progressive memory loss, difficulty with familiar tasks, word-finding difficulty, and getting lost in his own neighbourhood over the past year. MMSE score is 18/30. What is the most likely diagnosis?

Answer: Alzheimer disease

Alzheimer disease is the most common cause of dementia, characterised by insidious onset and progressive decline in memory (especially short-term), language, visuospatial skills, and executive function. MMSE <24 suggests cognitive impairment.

What is the mechanism of action of SSRIs in treating depression?

Answer: Block serotonin reuptake at the presynaptic neuron

SSRIs selectively inhibit the serotonin transporter (SERT) at the presynaptic neuron, blocking the reuptake of serotonin from the synaptic cleft. This increases serotonin availability in the synaptic cleft, enhancing serotonergic neurotransmission.