What is the nature of bipolar disorder, schizophrenia and multiple personalities?

Question

What is the nature of bipolar disorder, schizophrenia and multiple personalities?

Answer 1

They are all very, very different. Bipolar and schizophrenia, of the three are the most similar. This does not make them similar, mind.

Bipolar disorder is a mood disorder, charactorised by periods of mania and depression. It occurs in 1% of the population. It is linked to the neurochemical norapinephrine, G-protiens in the brain and the BAS (Behavoiral Activation System, motivation). There is a strong genetic componant (70% concordance rate in MZ twins) It is cured by drug therapy (lithium) but talking therapy is heavily advised, even if only to encourage them to take the drugs.

By contrast, Schizophrenia is a psychotic disorder which disturbs though, emotion and behavoir - commonly disordered thinking, faulty perception or attention, flat or inappropriate affect (no or wrong emotions). Patients commonly display delusions or hallucinations. It is one of the most severe disorders. There are many subtypes. There is a genetic factor (roughly 50% for MZ twins). It is heavily linked to the activity of dopamine (or excess dopamine receptors) and structural factors like a disordered cortex. It is treated primarily with anti-psychotic drugs, but again this has the best sucess alongside therapy.

Multiple Personalities - refered to as Dissociative Identity Disorder (DID) in the DSM -  is a dissociative disorder. Unlike the two above, it is usually linked to *great* traumatic experience, usually in early chidhood (the above are often triggered by stresses, sometime quite minor, often in early adulthood). It is charactorised by apparent alter-egos or personalities who take control at different times. Their memories are not accessable to other egos. It appears to be cognitive in cause - social role enactment, dissociation during abuse causes "separation" in the mind, or repression. Drug therapy is not affective (except sometimes for co-morbid disorders like PTSD) and talking therapy is used to attempt to recombine the egos by getting the patient to accept they are one person and to get them to access repressed and traumatic memories (the proposed cause of the disorder).

So they all have different causes, affects and cures.