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Focuses on pharmacological treatments, brain stimulation, and the medical management of disorders.
Imagine if a tiny chemical imbalance could completely alter your sense of self—and a single molecule or a pulse of electricity could bring 'you' back. How do we safely navigate the biological 'hardware' of the human mind?
Psychotropic medications treat mental disorders by modulating neurotransmitters—the chemical messengers of the brain. Antidepressants, specifically Selective Serotonin Reuptake Inhibitors (SSRIs), work by blocking the reabsorption (reuptake) of Serotonin () into the presynaptic neuron. This increases the concentration of in the synaptic cleft, enhancing mood signaling. Conversely, Antipsychotics (neuroleptics) primarily target Dopamine () pathways. First-generation antipsychotics act as antagonists that bind to receptors, reducing the overactive dopamine signaling associated with hallucinations and delusions in schizophrenia. Modern 'atypical' antipsychotics are more nuanced, targeting both and receptors to treat a broader range of symptoms with fewer motor side effects.
1. A neuron releases Serotonin () into the synapse to send a 'mood-boost' signal. 2. Normally, a reuptake pump removes the quickly to reset the system. 3. An SSRI molecule 'plugs' that pump. 4. Result: The stays in the synapse longer, repeatedly stimulating the receiving neuron.
Quick Check
How do SSRIs increase the availability of serotonin in the brain?
Answer
They block the reuptake process, preventing the sending neuron from reabsorbing the neurotransmitter, thus leaving more in the synapse.
When medication fails, clinicians may turn to brain stimulation. Electroconvulsive Therapy (ECT) involves brief electrical pulses to trigger a controlled seizure while the patient is under general anesthesia. Despite its historical stigma, modern ECT is highly effective for treatment-resistant depression, boasting an efficacy rate of approximately . A newer, non-invasive alternative is Transcranial Magnetic Stimulation (TMS). TMS uses a magnetic coil to induce small electrical currents in specific brain regions, like the left prefrontal cortex. Unlike ECT, TMS requires no anesthesia, has no memory-loss side effects, and allows the patient to remain fully awake during the procedure.
A patient with severe, suicidal depression has not responded to five different medications. 1. The psychiatrist considers ECT for rapid relief, despite the risk of temporary short-term memory loss. 2. For a patient with moderate depression who cannot tolerate medication side effects, the psychiatrist suggests TMS, which involves 20-minute sessions over several weeks with virtually no systemic side effects.
Quick Check
What is a major clinical advantage of TMS over ECT?
Answer
TMS is non-invasive, requires no anesthesia, and does not cause memory loss or seizures.
Biomedical treatment is not 'set it and forget it.' Medication management is the ongoing process of balancing therapeutic benefits against side effects. Long-term use of older antipsychotics can lead to Tardive Dyskinesia (TD), a permanent neurological condition characterized by involuntary muscle movements. Clinicians must also monitor the therapeutic window—the dosage range where a drug is effective but not toxic. For example, Lithium (used for Bipolar Disorder) has a very narrow window; too little is ineffective, while too much causes organ damage. This requires regular blood testing and 'polypharmacy' reviews to ensure different drugs aren't interacting dangerously.
A patient is prescribed Clozapine for treatment-resistant schizophrenia. 1. The clinician must order weekly blood draws to check for agranulocytosis (a dangerous drop in white blood cells). 2. The clinician uses the AIMS (Abnormal Involuntary Movement Scale) to screen for early signs of Tardive Dyskinesia. 3. If the patient's white blood cell count drops below a specific threshold (), the medication must be discontinued immediately.
Which neurotransmitter is primarily targeted by first-generation antipsychotics?
What is the primary mechanism of an SSRI?
Modern ECT is performed while the patient is awake to ensure they can report side effects.
Review Tomorrow
In 24 hours, try to explain the difference between an 'agonist' and an 'antagonist' and identify which one describes a typical antipsychotic's relationship with dopamine.
Practice Activity
Research the 'AIMS' scale used by clinicians. Try to identify the seven body areas clinicians check when monitoring for Tardive Dyskinesia.