Heiman et al [1] reported a possible link between DYT1 gene carrier-state and major depression (MD). They conclude that there is a shared biologic mechanism for MD and a childhood onset generalized form of dystonia (GD).
Although the pathophysiologic basis of primary focal dystonia (FD) is unknown and uncommonly associated with the DYT1 gene, [2] most investigators assume that the dysfunction in both GD and FD lies within basal ganglion networks. An association between MD and FD raises the possibility that primary FD pathophysiology also places affected individuals at risk for MD as in DYT1 carriers. If there are causal genetic factors in FD patients, then their first-degree relatives may also be at risk for MD.
Depression and anxiety are unusually prevalent in FD. [3] A recent investigation of MMPI results in a referred population of 224 cervical dystonia (CD) patients (mean age 55-years, 67% female, 33% an additional dystonic site) demonstrated a rate of 53% for anxiety (ANX) and 72% for depression (DEP). [4] Symptoms of DEP in FD may antedate dystonic clinical onset suggesting that the affective symptoms are not a reaction to an often painful, potentially disabling disorder. [3] We found that, of 195 CD patients, 18% had a history of psychiatric diagnosis antecedent to onset of dystonic symptoms.
Utilizing DSM-IV criterion referencing the rate of DEP in first-degree CD relatives in the above study was 28%, 34% alcohol abuse and 10% ANX disorder. [4] Scheidt et al [5] reported 13% of CD patients had a first-degree relative with a history of “severe mental disorder.” Recalled family history data may be flawed. However, if valid, these observations suggest that non-DYT1 based FD gene sites may also place individuals at dual risk for MD and FD. Although the rate of dystonia in first-degree relatives of FD subjects is less than 10%, families of CD patients have high rates of essential head tremor and scoliosis suggesting perhaps a genetic component with heterogenous clinical expression. [4]
Neurologists should be aware of concomitant mood and cognitive manifestations of focal and generalized dystonia patients. These data reinforce the reunion of mind and brain.
References
1. Heiman GA, Ottman R, Saunders-Pullman RJ, Ozelius LJ, Risch MJ, Bressman SB. Increased risk for recurrent major depression in DYT1 dystonia mutation carriers. Neurology, 2004; 63: 631-637.
2. Bressman SB, De Leon D, Raymond D, et al. Clinical-genetic spectrum of primary dystonia. Adv Neurol, 1998; 78: 79-91.
3. Jahanshahi M, Marsden CD. Depression in torticollis: a controlled study. Psychological Medicine, 1988; 18: 925-933.
4. Duane DD, Vermilion KJ. Cognition and affect in patients with cervical dystonia with and without tremor. Adv Neurol, 2004; 94: 179-189.
5. Scheidt CE, Heinen F, Nickel T, et al. Spasmodic torticollis – a multicentre study on behavioral aspects IV: psychopathology. Behav Neurol, 1996; 9: 97-103.