Increased dopamine transporter density in Parkinson's disease patients with social anxiety disorder

Presynaptic dopaminergic terminal imaging and non-motor symptoms assessment of Parkinson’s disease: evidence for dopaminergic basis?

“…Anxiety was measured using State Trait Anxiety inventory.Anxiety score was negatively correlated with binding potential values in left ventral striatum, left caudate, left locus coeruleus, left inferior thalamus and bilateral amygdala and medial thalamus ( p  = 0.05).Inverse relationship between the binding of [11C]-RTI32 in these regions and the severity of anxiety and mood disorders in these patients suggests a potential for both a dopaminergic and noradrenergic basis. This is an important PET study addressing a multi-neuro-transmitter basis of anxiety and depression in PD.Weintraub et al 66 2005Anxiety 99m Tc-TRODAT-176 PD patients and 46 healthy volunteers were assessed using the STAI and POMS.PD patients showed there to be a negative correlation using both State and Trait anxiety parameters with DaT uptake in the right anterior putamen (state anxiety [ r  = −0.24, p  = 0.04], Trait anxiety [ r  = −0.30, p  = 0.01]).Controlled data and this data is consistent with previous work in that dopaminergic dysfunction may be necessary for affective symptom development.Moriyama et al 78 2011Anxiety 99m Tc-TRODAT-132 PD patients who were assessed and diagnosed as having generalised SAD ( n  = 11) according to DSM-IV criteria.A positive correlation, using the Brief Social Phobia Scale (BSPS), was found specifically in the right ( r  = 0.37, p  = 0.04), left putamen ( r  = 0.43, p  = 0.02), and left caudate ( r  = 0.39, p  = 0.03).The study suggests a dopaminergic defect is plausible within the pathophysiological realms of social anxiety PD. However, another study suggests dopaminergic basis of anxiety.Di Giuda et al 70 2012Anxiety 123 I-FP-CIT21 PD patients had the HDRS, HARS, SHPS performed to assess anxiety and depression.Using HARS cut/off of 10/11 there was no significant difference in DaT availability between anxiety-PD patients ( n  = 17) and those without anxiety ( n  = 4), but this showed a trend towards lower uptake in the left caudate ( p  = 0.07) of anxious-PD patients.The study used a very small sample size which makes any meaningful comparison between anxious vs. non-anxious patients difficult.Erro et al 5 2012Anxiety 123 I-FP-CIT34 untreated PD patients evaluated using HADS-D, HADS-A scales, and BDI.Inverse correlation between the severity of anxiety and nigrostriatal DaT availability within the right caudate ( r  = −0.39, p  = 0.01) and left caudate ( r  = −0.31, p  = 0.03).A potential association between DaT defect and anxiety-PD symptoms as noted before.…”

“…Moriyama and colleagues, and Kaasinen and colleagues reported a positive correlation between dopaminergic DaT uptake within the striatum and social anxiety or personality traits and anxiety in patients, respectively. 78,79 The variation found here, suggests anxiety to be heterogeneous in origin with a partial dopaminergic basis. Remy and colleagues demonstrated a negative correlation between the severity of anxiety with binding at the locus coeruleus and bilateral amygdala using 11 C-RTI32, forging the concept of a DA-noradrenergic system involvement in PD-anxiety.…”

The clinical spectrum of anxiety in Parkinson's disease

“…The relationship between anxiety and PD, however, persisted when adjusted for anxiolytic use, suggesting that it is unlikely that medication alone is able to explain this association. Neurobiological theories propose that anxiety and motor symptoms of PD share common pathological mechanisms . Hence, anxiety may be an early manifestation of PD that can present years before the onset of motor symptoms …”

Affective disorders in Parkinsonʼs disease

“…The findings provide support for a neurobiological basis for SAD in Parkinson's disease and may indicate less neurode-generation in this patient population or alternatively decreased dopamine release at the synapse [23].…”