HD Lighthouse Contributing Editor's Comment: Gene carriers and those at risk who were found not to carry the Huntington's Disease gene were compared in terms of lifetime prevalence of psychiatric disorders and symptoms. The two groups did not differ significantly. Did these HD family members, both carriers and noncarriers, experience higher lifetime rates than the general population? This isn't clear; compared to some studies they experienced a higher rate of depression but not compared to other studies.

Rates of depression and irritability in gene carriers rose in the decade before clinical onset. With depression, the rate rose as onset neared while irritability rates were stable in the ten years before onset.

Huntington's Disease is always diagnosed clinically based on neurological signs assessed in office visits. However, we know from the Predict-HD study that onset does not involve abrupt changes but rather the crossing of a threshold. As individuals near onset or what is now being called 'manifest' HD, motor, cognitive, and psychological problems increase.

Information from studies like this is important for being proactive in dealing with the disease for two reasons. First, at risk people should not hesitate to go for treatment for depression out of concern that onset has occurred. It may or may not be a sign of HD since non gene carriers who are at risk and the general public not at risk also experience depression. but it needs to be treated to improve one's quality of life. Second, symptoms which interfere with work performance and relationships with others may occur even though the threshold to manifest HD hasn't clearly been crossed. People with the HD gene and their families who are seeking assistance with disability determination as well as support, counseling and medication for psychological symptoms and distress need to have their concerns taken seriously and not dismissed.

-- Marsha L. Miller, Ph.D.
Posted to the HDL: 27 Dec 2006

Psychiatric disorders in pre-clinical Huntington's disease

Julien CL, Thompson JC, Wild S, Yardumian P, Snowden JS, and Craufurd D

Background:
Psychiatric symptoms are a common feature of Huntington's disease (HD) and often precede the onset of motor and cognitive impairments. However, it remains unclear whether psychiatric changes in the pre-clinical period result from structural change or are a reaction to being at risk or simply a coincidental occurrence. Few studies have investigated the temporal course of psychiatric disorder across the pre-clinical period.

Objectives:
To compare lifetime and current prevalence of psychiatric disorder in pre-clinical gene carriers and non-carriers and to examine the relationship of psychiatric prevalence in gene carriers to temporal proximity of clinical onset.

Methods:
Lifetime and current psychiatric histories of 204 at-risk individuals (89 gene carriers and 115 non-carriers) were obtained using a structured clinical interview, the Composite International Diagnostic Interview (CIDI). Psychiatric disorders were classified using both standardised diagnostic criteria and a more subtle symptom-based approach. Follow-up of gene carriers (n = 51) enabled analysis of the role of temporal proximity to clinical onset.

Results:
Gene carriers and non-carriers did not differ in terms of the lifetime frequency of clinical psychiatric disorders or sub-clinical symptoms. However, gene carriers did report a significantly higher rate of current depressive symptoms. Moreover, the rate of depression increased as a function of proximity to clinical onset. CONCLUSIONS: Affective disorder is an important feature of the prodromal stages of HD. The findings indicate that depression cannot be accounted for by natural concerns of being at risk. There is evidence of a window of several years in which preclinical symptoms are apparent.

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Source: J. of Neurology, Neurosurgery, and Psychiatry 2006 Dec 18; [Epub ahead of print]

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