Antipsychotics That Worked for A First Episode May Not Work As Well a Second Time
In new research by Ofer Agid and colleagues, patients in their first schizophrenic episode who reached remission in response to one of two antipsychotic medications (risperidone or olanzapine) and relapsed due to medication non-adherence were re-treated with the same medication regimen that had brought about remission. Reinitiating the same treatment was not as successful in bringing about remission of the patients’ second psychotic episodes.
Patients showed different types of trajectories in their first remission, from immediate to gradual improvement, and these predicted parallel trajectories of their treatment response during the second episode, though the muted response to antipsychotics existed across the board. Dopamine is the main target of antipsychotic treatments, but its role in schizophrenia is not straightforward, and Agid and colleagues stress that response and relapse are multidimensional processes.
Editor’s Note: These data are consistent with the research of J.A. Lieberman and colleagues fifteen years ago, which showed that response to antipsychotic treatment is poorer in successive episodes of psychosis. The findings are also consistent with the idea of episode sensitization in mood disorders, developed by this author (Robert Post). Episode sensitization refers to the case in which greater numbers of prior depressions or manias are associated with faster relapse and a greater degree of treatment resistance.
The data raise major doubts about the common practice of quitting medications to see if remission can be maintained without them. There are dozens of studies in patients with schizophrenia showing that continuous treatment is more effective than intermittent treatment.
Jules Angst on the Long-Term Progressive Course of Mood Disorders
Jules Angst
At a symposium celebrating the retirement of Willem Nolen, a researcher who spent 40 years studying unipolar and bipolar disorder, from his position at Groningen Hospital in the Netherlands, his colleague Jules Angst discussed some recent findings. Angst is perhaps the world’s leading authority on the long-term course of unipolar and bipolar disorders based on his multiple prospective follow-up studies, some lasting 20-30 years.
The Sensitization-Kindling Model
Angst described evidence that supports the sensitization-kindling model of recurrent mood disorders, which this editor (Robert Post) described in 1992. Episodes tend to recur faster over time, i.e. the well interval between episodes becomes progressively shorter. While stressors often precipitate initial episodes, after multiple occurrences, episodes also begin to occur spontaneously (in the absence of apparent stressors).
This type of progressive increase in response to repetition of the same stimulus was most clearly seen in animal studies, where repeated daily electrical stimulation of the amygdala eventually produced major motor seizures (i.e. amygdala kindling). Daily electrical stimulation of rodents’ amygdala for one second initially produced no behavioral change, but eventually, minor and then full-blown seizures emerged. Once enough of the stimulated full-blown amygdala-kindled seizures had occurred, seizures began to occur spontaneously (i.e. in the absence of the triggering stimulation).
The analogy to human mood disorders is indirect, but kindling provides a model not only for how repeated triggers eventually result in full-blown depressive episodes, but also for how these triggered depressive episodes may eventually occur spontaneously as well.
Long-Term Treatment of Mood Disorders
Angst also discussed long-term treatment of mood disorders. He has found that long-term lithium treatment not only reduces suicides in patients with bipolar disorder, but also reduces the medical mortality that accompanies bipolar disorder.
Angst noted his previous surprising observations that in unipolar disorder, long-term maintenance treatment, even with low doses of tricyclic antidepressants, prevents suicide. Previously, researchers Ellen Frank and David Kupfer of Western Psychiatric Institute and Clinic at the University of Pittsburgh Medical Center had found that when patients with recurrent unipolar depression who had been stable for 5 years on the tricyclic antidepressant nortriptyline were blindly switched to half their original dose, about 90% rapidly relapsed into a new episode of depression. Their data helped establish the prevailing view that maintenance treatment with the full-dose regimen required to achieve a good initial acute response is also the optimal approach to long-term continuation and prophylactic treatment.
Angst found good results even at low doses, but his data may not be in conflict with Frank and Kupfer’s, as a person who responds well acutely to low doses may also be able to maintain good enough response to them to prevent recurrences in the long term.
Incidence of Bipolar Disorder in Adolescents Similar to Incidence in Adults
Angst also presented data from the Adolescent Supplement to the National Comorbidity Study (NCS-A), which analyzed interviews with approximately 10,000 adolescents (aged 13-17) in the US. He found a 7.6% incidence of major depression, a 2.5% incidence of bipolar I or II disorder, and a 1.7% incidence of mania. There was an even higher incidence of sub-threshold bipolar disorder, when there are not enough symptoms or a long enough duration of symptomatology to meet diagnostic criteria for bipolar I or II disorder. These data published by Merikangas et al. in 2009 provide clear epidemiological data that there is a substantial incidence of bipolar disorder in adolescents in the US, roughly similar to that seen in adults.
How Illness Progresses In The Recurrent Affective Disorders
This editor (RM Post) in collaboration with Jacqueline Fleming and Flavio Kapczinski published the article “Neurobiological mechanisms of illness progression in the recurrent affective disorders” in the Journal of Psychiatric Research this year. The article built on several themes about the progression of bipolar illness that had been explored in previous research.
These themes include:
- The likely acceleration of repeated episodes as a function of the number of prior episodes (episode sensitization)
- The increased responsivity of the illness to repeated stressors (stress sensitization)
- The increased behavioral reactivity to repeated use of psychomotor stimulants such as cocaine (stimulant-induced behavioral sensitization)
Not only are these observations well documented in the scientific literature, but recent observations also suggest that each type of sensitization can show cross-sensitization to the other two types. That is, individuals exposed to repeated stressors are more likely both to experience affective illness episodes and to adopt comorbid substance abuse. In a similar way, episodes of an affective disorder and stressors may also be associated with the relapse into drug administration in those who have been abstinent.
In addition to these mechanisms of illness progression in the recurrent affective disorders, the new article reviews the literature showing that the number of affective episodes or the duration of the illness appear to be associated with a variety of other clinical and neurobiological variables.
The number of affective episodes a patient experiences is associated with the degree of cognitive dysfunction present in their bipolar illness, and experiencing more than 4 episodes of unipolar or bipolar depression is a risk factor for dementia in late life. A relative lack of response to most treatments is also correlated with the number of prior episodes, and this holds true for response to naturalistic treatment in general. While most of these data are correlational and the direction of causality cannot be ascertained for certain, it is likely that the number of affective episodes and/or their duration could account for and drive difficulties with treatment and with cognitive function.
If this were the case, one would expect to see a variety of neurobiological correlates with the number of prior episodes or duration of illness, and in the article we summarize those that have been found in unipolar and bipolar disorder. Considerable data indicate that cortical volume and degrees of prefrontal cortical dysfunction can vary as a function of number of prior episodes. There is evidence that increased activity of the amygdala and the nucleus accumbens are also related to episodes or duration of illness. In those with unipolar depression, the volume of the hippocampus is decreased with longer duration of illness. Read more
