Biological Treatment 3.1 Treatment of disorders

Biological interpretation of MDD

A chemical imbalance. This oversimplifies a complex disorder

SSRIs (Selective Serotonin Reuptake Inhibitors)

A class of antidepressants that increase serotonin levels in the brain. Plays a crucial role in mood, appetite, and many other aspects.

Serotonin process

1. Release into the brain: neurons communicate with each other through neurotransmitters. A presynaptic neuron releases serotonin into the synapse

2. Binding. Serotonin travels across the synapse and binds to receptors on the postsynaptic neuron, sending a signal

3. Reuptake. After the signal, the presynaptic neuron reabsorbs the serotonin through a transporter. This process clears the synapse, making the system ready for a new signal.

How do SSRIs intervene?

- Blocks serotonin transporters on the presynaptic neuron

- More serotonin is available as the reuptake process is blocked, so serotonin stays in the synapse for longer periods of time.

- Prolonged presence of serotonin leads to enhanced and sustained signalling between neurones

- Over time, increased serotonin activity is believed to help improve mood and alleviate symptoms of depression/anxiety

Elkin et al. (1989) Aim

To investigate if there was any significant difference in the effectiveness of three approaches to therapy (CBT, IPT, and drugs)

Elkin et al. (1989) Research Method

Longitudinal study

Elkin et al. (1989) Participants

250 MDD patients

Elkin et al. (1989) Procedure

Participants were randomly assigned to one of four treatment conditions for 16 weeks (IPT, CBT, imipramine, or placebo). Imipramine and placebo conditions were paired with clinical management for minimal support due to ethics. 28 therapists were involved. Patients were carefully monitored, with many assessments carried out before, during, and after the study. The assessment received information from both the patient and the therapist (blind) as well as significant others from the patient's life

Elkin et al. (1989) 3 Main areas of assessment

1) Symptoms

2) Life functioning

3) Functioning in relation to particular treatment approaches

Elkin et al. (1989) Findings

No significant differences in reduction of depression/improvement of functioning between CBT, IPT, or imipramine plus clinical management. Imipramine was faster in reducing depressive symptoms, but all were successful by 16 weeks. The outcome was influenced by initial severity of symptoms.

Elkin et al. (1989) Conclusion

The three treatments achieved significant and equivalent degrees of success, proving to be far superior to the placebo group.

Elkin et al. (1989) Strengths

Data triangulation increasing reliability

Elkin et al. (1989) Limitations

- Avoiding confounding behaviours led to a less representative sample

- Goal of each treatment was different

- Difficult to compare treatments due to array of symptoms and origins from each patient

- Possible demand characteristics/observer bias

Kirsch and Sapirstein (1998) Aim

To evaluate the effectiveness of SSRIs in treating depression

Kirsch and Sapirstein (1998) Research Method

Meta-analysis

Kirsch and Sapirstein (1998) Procedure

A meta-analysis was carried out of all clinical trials of SSRIs submitted to the FDA, with 47 trials in total. Studies whose findings were not previously reported were also included.

Kirsch and Sapirstein (1998) Findings

For patients with mild to moderate depression, the difference between SSRIs and placebo was relatively small. At least 75% of the improvement seen with SSRIs was also seen with the placebo. Patients with severe depression saw a larger difference between SSRIs and placebos. Roughly half of studies failed to find a statistically significant difference between SSRIs and placebos.

Kirsch and Sapirstein (1998) Conclusion

SSRIs are not as effective as drug companies have claimed, especially in patients with mild to moderate depression. Given the side effects, they may not be worthwhile for patients with mild depression.

Kirsch and Sapirstein (1998) Strengths

Publication bias eliminated

Kirsch and Sapirstein (1998) Limitations

Not all studies may have been carefully conducted