d,l-fenfluramine response in impulsive personality disorder assessed with [18F]fluorodeoxyglucose positron emission tomography

Synaptic pathology in the anterior cingulate cortex in schizophrenia and mood disorders. A review and a Western blot study of synaptophysin, GAP-43 and the complexins

There are several reports of ultrastructural and protein changes affecting synapses in the anterior cingulate cortex in schizophrenia. Altered cytoarchitecture has also been described in this region in schizophrenia as well as in mood disorders. In this paper we review the literature and present a new study investigating synaptic abnormalities in the anterior cingulate cortex (area 24) in the Stanley Foundation brain series. We used Western blotting to assess four synaptic proteins: synaptophysin, growth-associated protein-43 (GAP-43), complexin I and complexin II, which inform about somewhat different aspects of the synaptic circuitry. Synaptophysin, complexin II and GAP-43 were reduced in bipolar disorder. The decreases correlated with the duration of illness and tended to be greater in subjects without a family history. Complexin II was also reduced in major depression. Complexin I and the housekeeping protein beta-actin did not differ between groups. None of the proteins changed significantly in schizophrenia. The results indicate the presence of a synaptic pathology in the anterior cingulate cortex in mood disorders, especially bipolar disorder. The abnormalities may contribute to the dysfunction of cingulate neural circuits. The loss of synaptophysin is suggestive of decreased synaptic density whilst the decrease in GAP-43 may denote impaired synaptic plasticity and the reduction of complexin II but not complexin I implies that the alterations particularly affect excitatory connections. The reductions may be progressive.

Relationship between 5-HT function and impulsivity and aggression in male offenders with personality disorders

BACKGROUND

Reduced serotonergic (5-HT) function and elevated testosterone have been reported in aggressive populations.

AIMS

To investigate relationships between impulsivity, aggression, 5-HT function and testosterone in male offenders with personality disorders.

METHOD

Sixty male offenders with DSM-III-R personality disorders and 27 healthy staff controls were assessed using the Special Hospital Assessment of Personality and Socialisation (SHAPS), impulsivity and aggression ratings, d-fenfluramine challenge and plasma hormone concentrations.

RESULTS

The SHAPS non-psychopaths and those with schizoid personality disorders had enhanced 5-HT function (prolactin response to d-fenfluramine). Reduced 5-HT function was found in offenders with DSM-III-R borderline personality disorders and those with a history of repeated self-harm or alcohol misuse. The 5-HT function was inversely correlated more strongly with impulsivity than with aggression. Plasma testosterone correlated positively with aggressive acts. The SHAPS primary psychopaths had lower initial cortisol and higher testosterone concentrations than controls.

CONCLUSIONS

Future studies are needed to investigate regional brain 5-HT function.

The neuropsychopharmacology of criminality and aggression

Although the idea that aggression has biological components is not a new one, recent research in genetics, neuropsychopharmacology, and neuroimaging has helped clarify the biological contributions to aggression. Studies to date have focused on serotonergic function and impulsive aggression. Reduced levels of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) are associated with impulsive aggression. Pharmacochallenge studies have found decreased serotonergic responsiveness associated with impulsive aggression. Neuroimaging studies suggest a role for the prefrontal cortex, along with other regions of the brain, in the expression of aggression. Serotonin is not the only aspect of brain function implicated in impulsive aggression, and further work is being done on other neurotransmitters and neuropeptides.

Dysfunction in the neural circuitry of emotion regulation--a possible prelude to violence

Emotion is normally regulated in the human brain by a complex circuit consisting of the orbital frontal cortex, amygdala, anterior cingulate cortex, and several other interconnected regions. There are both genetic and environmental contributions to the structure and function of this circuitry. We posit that impulsive aggression and violence arise as a consequence of faulty emotion regulation. Indeed, the prefrontal cortex receives a major serotonergic projection, which is dysfunctional in individuals who show impulsive violence. Individuals vulnerable to faulty regulation of negative emotion are at risk for violence and aggression. Research on the neural circuitry of emotion regulation suggests new avenues of intervention for such at-risk populations.

Increased left posterior parietal-temporal cortex activation after D-fenfluramine in women with panic disorder

It is unclear whether the functional changes found in panic disorder reflect disturbed physiology of particular neurotransmitters. One method of investigating altered neurotransmission is to assess regional brain activations in response to agonist challenges. D-Fenfluramine is a medication that induces neuronal release of serotonin. Using ¿15OH(2)O and positron emission tomography (PET), measurements of regional cerebral blood flow (rCBF) were done at t=-20, -5, +20 and +35 relative to the IV D-fenfluramine injection (t=0) in nine panic-disordered and 18 healthy subjects. Subjects were otherwise healthy, right-handed, non-smoking and not taking psychotropic medication. ¿15OH(2)O PET scans were assessed with Statistical Parametric Mapping using individual global cerebral blood flow as a covariate. Comparisons of the (baseline) first two scans between healthy and panic-disordered subjects showed a decreased rCBF in the left posterior parietal-superior temporal cortex in the patient group. Fenfluramine-induced increases as defined by the last two scans minus the first two scans were compared between groups and a significantly greater increase in the same left posterior parietal-superior temporal region was found in panic-disordered subjects. Consistent with this finding, differences between the last two scans (post-fenfluramine) of the healthy and panic-disordered subjects showed an increased rCBF in the left superior temporal cortex in panic-disordered subjects. Functional pathology in the left parietal-superior temporal cortex in panic disorder may be related to abnormal modulation by serotonin.

Fenfluramine challenge in unipolar depression with and without anger attacks

We have previously hypothesized that patients with major depression and anger attacks may have a greater central serotonergic dysregulation than depressed patients without such attacks. We wanted to compare the prolactin response to fenfluramine challenge, as an indirect measure of central serotonergic function, in depressed patients with and without anger attacks. We recruited 37 outpatients (22 men and 15 women; mean age: 39.5+/-10.5) with DSM-III-R major depressive disorder, diagnosed with the SCID-P. Their initial 17-item Hamilton Rating Scale for Depression score was >/=16. Patients were classified as either having or not having anger attacks with the Anger Attacks Questionnaire. All patients received a single-blind placebo challenge followed by a fenfluramine challenge (60 mg orally) the next day. Plasma prolactin measurements were obtained with double antibody radioimmunoassay before and after both placebo and fenfluramine challenges, and fenfluramine and norfenfluramine blood levels after each challenge were determined by gas chromatography. Of the 37 study participants, 17 (46%) were classified as having anger attacks. There were no significant differences in age, gender, fenfluramine, or norfenfluramine blood levels between depressed patients with and without anger attacks. Depressed patients with anger attacks showed a significantly blunted prolactin response to fenfluramine challenge compared to patients without anger attacks. As previous studies have shown blunted prolactin responses to fenfluramine in impulsive aggression among patients with personality disorders, our results support our hypothesis that depressed patients with anger attacks may have a relatively greater serotonergic dysregulation than depressed patients without these attacks.

Prolactin response to D-fenfluramine and suicidal behavior in depressed patients

Previous studies of the prolactin response to D-fenfluramine in depressed patients have yielded inconsistent results. This may be because they did not address the question of suicidality. We carried out this study to test the hypothesis that lower prolactin response to D-fenfluramine is more closely associated with suicidal behavior than with depression itself. A D-fenfluramine test was performed in a sample of 18 healthy control subjects and in 85 drug-free inpatients with a DSM-III-R diagnosis of major depressive episode (49 with a history of suicide attempt, 36 without). Depressed inpatients with a history of suicide attempt showed a significantly lower prolactin response to D-fenfluramine compared to depressed inpatients without such a history and compared to control subjects. Healthy control subjects and depressed inpatients without a history of suicide attempt showed comparable levels of prolactin after D-fenfluramine. Time elapsed since suicide attempt did not influence prolactin level (baseline or post-stimulation). Results show that in our depressed drug-free inpatient sample, prolactin response to D-fenfluramine seems to be a marker of suicidality, but not of depression itself. We suggest that it is a trait marker of suicidality.

Relationship between depression and borderline personality disorder

The frequent occurrence of depressive symptoms in patients with borderline personality disorder has generated considerable interest in the nature of the relationship between borderline personality disorder and the depressive disorders. Data from the perspectives of phenomenology, biology, family history, course of illness, comorbidity patterns, and treatment response have been brought to bear on the question. Reviews based on research available by 1985 and 1991, respectively, arrived at differing conclusions: (1) that both disorders shared common but non-specific sources, and (2) that the two disorders were unrelated but co-occurred because of the high prevalence of each. Since the time of these reviews, additional evidence has become available from a wider range of biological investigations, better controlled comorbidity studies, studies of the relationship of psychosocial stressors to the course of each disorder and neuroimaging studies. In reviewing the more recent findings, we propose the less parsimonious hypothesis that the disorders co-occur, both because they share some common biological features and because the psychosocial sequella of each can contribute to the development of the other.

A fenfluramine-activated FDG-PET study of borderline personality disorder

BACKGROUND

Impulsive aggression in patients with personality disorders is associated with diminished levels of cerebrospinal fluid (CSF) 5-HIAA, blunted neuroendocrine responses to serotonergic agonists, and decreased glucose utilization in the prefrontal cortex. We tested the hypothesis that impulsive aggression in borderline personality disorder (BPD) may be associated with diminished serotonergic regulation in the prefrontal cortex, using positron-emission tomography (PET) neuroimaging during pharmacologic challenge with d,l fenfluramine (FEN).

METHODS

A 2-day, single-blind, placebo-controlled FEN challenge study was conducted in five patients with BPD (and no Axis I MDD) and eight healthy control participants. On Day 1, 4 mCi [(18)F]-fluorodeoxyglucose (FDG) was injected 3 hours after ingestion of placebo; on Day 2, FDG was injected 3 hours after ingestion of.8 mg/kg to 60 mg of d,l fenfluramine. After 30 min, a 45-min emission scan was acquired on the Siemans/CTI 951r/31 scanner. PET data were aligned to MR images and analyzed by Statistical Parametric Mapping (SPM96).

RESULTS

In response to placebo, uptake of FDG was greater in control participants than patients in large areas of the prefrontal cortex including medial and orbital regions bilaterally (BA 10-11), left superior temporal gyrus, and right insular cortex. There were no areas in which patients had greater relative regional uptake than control participants. In response to FEN, relative regional uptake of FDG (relative to placebo) was greater in control participants compared to patients in medial and orbital regions of right prefrontal cortex (BA 10), left middle and superior temporal gyri (BA 22-23), left parietal lobe (BA 40), and left caudate body.

CONCLUSIONS

Patients with BPD have diminished response to serotonergic stimulation in areas of prefrontal cortex associated with regulation of impulsive behavior.

Low HDL cholesterol, aggression and altered central serotonergic activity

Many studies support a significant relation between low cholesterol levels and poor impulse, aggression and mood control. Evidence exists also for a causal link between low brain serotonin (5-HT) activity and these behaviors. Mechanisms linking cholesterol and hostile or self-destructive behavior are unknown, but it has been suggested that low cholesterol influences 5-HT function. This study was designed to explore the relationship between plasma cholesterol, measures of impulsivity and aggression, and indices of 5-HT function in personality disordered cocaine addicts. Thirty-eight hospitalized male patients (age 36.8+/-7.1) were assessed with the DSM-III-R, the Buss-Durkee Hostility Inventory (BDHI), the Barratt Impulsiveness Scale (BIS) and the Brown-Goodwin Assessment for Life History of Aggression. Fasting basal cholesterol (total, LDL and HDL) was determined 2 weeks after cocaine discontinuation. On the same day 5-HT function was assessed by neuroendocrine (cortisol and prolactin) and psychological (NIMH and 'high' self-rating scales) responses following meta-chlorophenylpiperazine (m-CPP) challenges. Reduced neuroendocrine responses, 'high' feelings and increased 'activation-euphoria' following m-CPP have been interpreted as indicating 5-HT alterations in a variety of psychiatric conditions. Significantly lower levels of HDL cholesterol were found in patients who had a history of aggression (P=0.005). Lower levels of HDL cholesterol were also found to be significantly associated with more intense 'high' and 'activation-euphoria' responses as well as with blunted cortisol responses to m-CPP (P=0.033, P=0.025 and P=0.018, respectively). This study gives further support to existing evidence indicating that in some individuals, the probability of exhibiting impulsive and violent behaviors may be increased when cholesterol is low. It also suggests that low cholesterol and alterations in 5-HT activity may be causally related.

The biology of impulsivity and suicidality

Abnormalities of 5-HT and noradrenergic functioning have been implicated in aggressive impulsivity, SIB, and suicidal behavior. The role of DA and GABA in human studies of these behaviors requires further investigation. Most studies suggest that impulsive aggression is related to lower levels of CNS 5-HT. Some studies demonstrate that increasing NE correlates to impulsive aggression, whereas other studies demonstrate an opposite relationship. The role of NE in impulsive aggressive behavior is still unclear. Self-injurious behavior is similar to impulsive aggression in that it seems to be mediated by the neurotransmitter systems previously mentioned. For example, the presence of lower levels of 5-HT and abnormalities in the DA system are related to SIB in patients with BPD and depression. SIB severity also seems to be influenced by neglect (e.g., severe isolation during rearing). As animal studies suggest, increasing the amount of isolation and an earlier onset of isolation increase the severity of SIB. Suicidal behaviors and the lethality of suicide attempts may also be linked to the abnormalities in neurotransmitter systems similar to those found in patients with impulsive aggression and SIB, namely, lowered 5-HT transmission and enhanced DA and NE functioning. Understanding the biological triggers of impulsive aggression or SIB may allow for the evaluation of suicidal attempts and completion from a different perspective and, in conjunction with genetic predictors, may eventually help with the early prediction and prevention of suicidal behaviors. Additional studies of live subjects and postmortem brains will assist in clarifying the neurobiology of suicidal behaviors that are common to many disorders and are clinically relevant to BPD.

Neurotransmitter dysfunction in patients with borderline personality disorder

Neurotransmitter system dysfunction may contribute to the borderline personality disorder traits of impulsive aggression and affective instability. This article reviews evidence from neurochemical assays, receptor-density studies, neuroendocrine-challenge paradigms, functional neuroimaging studies, and candidate-gene research, which converge to identify particular neurotransmitter systems that seem to be dysregulated in patients with borderline personality disorder.

Impulsive aggression in borderline personality disorder

Impulsive aggressive behaviors that include physical aggression directed towards others, self-mutilation, suicide attempts, domestic violence, substance abuse, and property destruction account for a substantial portion of the morbidity and mortality associated with personality disorders, in particular borderline personality disorder (BPD). Recent genetic, neurobiologic, and diagnostic studies suggest a dimensional approach to BPD symptomatology with impulsive aggression as one of the core dimensions for the disorder. The underlying biologic basis for impulsive aggression is centered on the serotonin hypothesis; that central 5-HT function is inversely related to aggression and suicidality. More recent research refines the theory to include associated brain regions, receptor types and neuromodulators potentially involved in the etiology of aggressivity. Treatment utilizes this information with substantial progress in well-designed placebo-controlled studies of selective serotonin reuptake inhibitors such as fluoxetine, and open-label series of atypical neuroleptics, mood stabilizers, and opioid antagonists