Biological treatments for mood disorders

HideShow resource information

Exogenous vs Endogenous- Unipolar

  • Exogenous- Depression follows clear preceding events, something (environmental) has happened to the individual to cause depression
  • Endogenous- Depression occurs in the absence of preceding events, appears to be caused by internal (biological) factors
  • Seems to be no obvious cause for a person's depression
  • Endogenous depression is assumed and a biological treatment is likely to be chosen by a clinician
1 of 9

1. Antidepressant medication- Unipolar

Monoamine oxidase inhibitors (MAOIs)

  • Monoamine oxidase in an enzyme that interacts with and breaks down the monoamines serotonin (5-HT) and noradrenaline (na) once a message has been relayed across the synapse
  • Function- Believed that depressed patients have low levels of 5-HT and na, monoamine oxidase inhibitors prevent the destruction of these neurotransmitters allowing for levels to accumulate in the synapse and remain for longer- neurotransmission returns to normal and symptoms are reduced
  • Effectiveness- 50% of mild to severely depressed patients who take MAOIs recover from depression. Good for depression where anxiety is a symptom
  • Side effects-
    Insomnia, dry mouth and dizziness
    >Interact with certain foods causing dangerously high blood pressure and sudden death
2 of 9

2. Antidepressant medication- Unipolar

Tricyclic Antidepressants (TCAs)

  • Thought that the reuptake mechanism may be too successful in some people causing low serotonin (5-HT) and noradrenaline (na) levels in the synapse
  • Function- Block the reuptake of 5-HT and na, leaving the neurotransmitter in the synapse for longer. This results in increased activity and a reduction in symptoms
  • Effectiveness- TCAs are commonly prescribed. 60-65% effective and do not require dietary restrictions
  • Side effects-
    >Dry mouth, confusion, impaired memory, sedation, analgesia (pain relief)
    >Fatal in overdose, GPs must take care when prescribing this drug to suicidal/severly depressed patients
3 of 9

3. Antidepressant medication- Unipolar

Selective serotonin reuptake inhibitors (SSRIs)

  • The most recently discoevered antidepressants, include Sertraline (Lustral) and Fluoxetine (Prozac)
  • Function- Only block the reuptake of serotonin (5-HT) and don't affect other neurotransmitters or biochemical processes --> patients experience fewer side effects
  • Effectiveness- Equally as effective as Tricyclic antidepressants (65%) but are often preferred as they don't have the same side effects (not fatal in overdose). More suitable for severly depressed/suicidal patients
  • Side effects-
    >Headaches, nervousness, insomnia, sweating
    >Sexual dysfuntion reported in 40-60% of patients taking SSRIs (thought to be a significant contributor to non-compliance)
4 of 9

1. Evaluation of antidepressant medication- Unipol


  • More than half of patients improve when taking these drugs, BUT around half don't suggesting not all depression is biological in cause (e.g. exogenous depression)
  • Improvement is not experperienced until 4-6 weeks after the start of the course despite neurotransmitter levels returning to normal in only a few days- questions whether low serotonin (5-HT) and noradrenaline (na) levels are the cause of depression, issues with patient compliance due to there being no immediate effect
  • Patient must continue to take the drug for at least 6 week to reduce risk of relapse- patients may stop taking the drug prematurely once recovered

Side effects

  • These may make the patient reluctant to take the drug due to the resulting unpleasant symptoms
  • E.g. MAOIs require patients to go on a strict diet
5 of 9

2. Evaluation of antidepressant medication- Unipol

Treats the symptoms not the cause

  • Criticised as a 'quick fix' due to the medication not actually treating the cause
  • Assumes depresion is endogenous and so ignores other potential factors


  • Due to the cause not being addressed, relapse is a problem
  • Research shows that once a person has recovered from one episode of depression, they have an increased vulnerability to further episodes
  • Suggested that treatment should take a multi-modal approach- therapy and medication 
6 of 9

Treatment for Bipolar


  • Has mood stabilising effects- treats both the manic and depressive phases of the disorder
  • Not fully understood how it works- closely related to sodium so thought it may increase the presynaptic uptake of noradrenaline (na) OR it may inhibit the release of na
  • Effectiveness- 80% efficacy in treating manic and depressive symptoms, issues with compliance have meant that studies have found that less than 40% of patients remain well= HIGH efficacy, LOW effectiveness
  • Side effects-
    >Vomiting, sluggishness, cognitive slowing, kidney damage, weight gain (30% obesity)
    >Toxic problems
    >Achieving the correct dosage for any individual is a delicate process


  • The course of the illness after stopping lithium treatment is worse- Lithium is a lifelong treatment
  • Psychological support and family therapy can help the patient stay on the drug
7 of 9

Efficacy vs Effectiveness


  • How successful a drug is in relieving the symptoms of a disorder


  • The success of the drug as a treatment
  • Highly dependant on the severity of side effects and a patient's willingness to comply with dosage requirements
8 of 9

Overall Effectiveness of Therapies

  • Smith and Glass- reviewed 400 studies of a wide variety of treatments and found that all were more effective than no treatment at all. They also found that patients that discontinue antidepressant medication have a 50% chance of relapse in the first 6 months after therapy unless it is folled by psychotherapy--> suggests and eclectic approach is most effective
  • Relapse rates (12 weeks of...)- Drug therapy, no continuation--> 50%, Drug therapy, continued for 1 yr--> 32%, Cognitive therapy, no continuation--> 21%, Drug and cognitive, no continuation--> 15%
  • Importance of drug therapy- elevate a seriously depressed patient's mood to enable them to function cognitive, behavioural or psychodynamic therapy sessions
  • ECT- helpful for 50-80% of severely depressed, drug resistant individuals  
9 of 9


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Mood Disorders resources »