Amotivation is associated with smaller ventral striatum volumes in older patients with schizophrenia

Abstract

We replicate and extend the finding of reduced VS volumes with greater amotivation. We demonstrate this relationship uniquely beyond the potential contributions of striatal D R blockade by antipsychotics. Elucidating the structural correlates of amotivation in schizophrenia may help develop treatments for this presently irremediable deficit.

Apathy is not associated with reduced ventral striatal volume in patients with schizophrenia

“…Capitalizing on a sample of SZ patients exhibiting blunted VS BOLD activation related to apathy, the present study aimed to extend previous work on the relationship between structural VS abnormalities and the severity of apathy in schizophrenia. Although applying the same methodological approaches as two recently published studies (Caravaggio et al, 2018a;Roth et al, 2016), we could not replicate the previously observed association between apathy and reduced VS volume in a larger sample. Given the fact that we have found blunted VS activation related to apathy in the same dataset (Fig.…”

“…The negative findings of the present study raise the question whether differences in sample characteristics (compared to (Caravaggio et al, 2018a;Roth et al, 2016)) are able to explain the missing association between reduced VS volume and apathy. Relevant confounding factors are differences in age, duration of illness and antipsychotic medication dose (Amato et al, 2017;Haijma et al, 2013;Hashimoto et al, 2018;van Erp et al, 2016).…”

“…Compared to the patient group in the current study (n=60, age, mean=30.5, SD=8.4), patients in the study from Roth et al were on average almost 10 years older (n=23, age, mean=39.4, SD=12.3) and on average around 30 years older in the study from Caravaggio et al (n=41, age, mean=60.2, SD=6.7) (Caravaggio et al, 2018a;Roth et al, 2016). Accordingly, in the latter study, patient's illness duration was on average over 25 years longer and apathy/amotivation correlated positively with age (Caravaggio et al, 2018a). In a recent ENIGMA meta-analysis van Erp.…”

“…Using Voxel-based morphometry, Roth et al found that apathy (measured with the Apathy Evaluation Scale) was associated with reduced right VS volume, but not left VS volume, in 23 individuals with a diagnosis of schizophrenia or schizoaffective disorder (Roth et al, 2016). This finding was replicated by Caravaggio and colleagues who observed a relationship between apathy (PANSS amotivation factor) and both left and right VS volume using a different method -the "Multiple Automatically Generated Templates (MAGeT-Brain)" algorithm (Caravaggio et al, 2018a). The study from Caravaggio and colleagues also extended previous work showing in 41 older schizophrenia patients that the relationship between VS volume was specifically related to individual levels of amotivation (not diminished expression) and independent of antipsychotic occupancy of striatal dopamine D2/3 receptors measured with positron emission tomography (Caravaggio et al, 2018a).…”

“…(Mawlawi et al, 2001). In total, both ROI approaches results in 4 VS ROIs (2x left, 2xright) and 2 DS ROIs (1xleft, 1xright) (C) Example of how MAGeT delineates the striatal subdivisions on an individual subject scan (Caravaggio et al, 2018a).…”