Heterotypic Continuity & Comorbidity
Heterotypical continuity means that an underlying (developmental) process or impairment stays the same, but the manifestations do not stay the same. For example a child with autism might first show impairments of non-verbal skills and problems in eye-contact. In a later developmental stage the manifestations would be different, such as stereotypical behaviour or language problems.
In psychopathological progression one disorder can be seen as a risk factor for developing another disorder. For example eating disorders such as anorexia nervosa have a influence on neurotransmitter levels such as serotonin. Imbalance of that neurotransmitter is related to general anxiety disorder and depression. In that way eating disorder do not cause depression, but it certainly puts the individual at a higher risk.
Whereas comorbidity is a correlational construct, the concepts of heterotypic continuity and psychopathological progression are causal theories in a developmental framework, that take the development of the individual into account. One could argue that, where comorbidity uses data to state a fact, the other two concepts actually try to explain the process.
Homeotypic continuity can be seen as the opposite of heterotypic continuity. Whereas in heterotypic continuity the process stays the same and the manifestations change, in homeotypic continuity the manifestations stay the same, but the underlying process changes. For example a child might resort to aggression, because it lacks the necessary skills to make contact with peers at schools. Later in life aggression against peers might be mainly attributed to an antisocial personal disorder.
The implicit Contract by Therapist and Patient in Psychotherapy
Idea for an experiment:
I proposed to prime therapists with the case of a patient that could easily be identified as one disorder (for example depression or dementia) and then present another case in which the information is ambiguous and thus allowing the possibility for both disorders to be present. Having read the articles by Chadwick, Williams and Mackenzie (2003) I wonder if disorder specific information is the “big thing” about case formulation. Rather it could be seen as a contract between the therapist and the client in which the therapist can prove his knowledge and skill to the client by structuring the clients’ life history, behaviour and cognitions in a meaningful way. A case formulation is like the therapist saying: “I know what is wrong with you, I have decided to help you and that is how were are going to do it!”. For the patient this might raise hope and contribute to remoralization. For the therapist the case formulation might be an important step-by-step guideline on what to concentrate on in therapy and how to do it. I stick with my experiment, but I would like to include another sub experiment. The case formulations by the novice and the expert are shown to the patient and he or she rates them in on their affective impact. As a control condition the patient could receive either personal case formulations that structure behaviour, life story and cognition in parsimonious ways, but do not reference to specific disorders. As an alternative, standard case formulations could be used.
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